This document discusses dye-sensitized solar cells (DSSCs) and provides context about the need for alternative energy sources. It outlines three hypotheses about how dye loading time and dye structure may impact the solar conversion efficiency of DSSCs. Key factors that determine solar cell performance are also reviewed, such as open circuit voltage, short circuit current, fill factor, electron lifetime, and incident photon-to-current efficiency. The document provides background information on DSSCs to support experiments that will test the effects of different dyes and dye loading times.

1. 2015
Kiana Lee
Niles North High School
3/7/2015
Characterization of Ruthenium and Organic
Based Dye Sensitized Solar Cells with Time
Dependent Dye Loading

2. Lee
1
Table of Contents
Table of Contents........................................................................................................................................ 1
Acknowledgements ..................................................................................................................................... 2
Purpose ........................................................................................................................................................ 3
Hypothesis and Rationale........................................................................................................................... 4
Review of Literature................................................................................................................................... 5
Materials.................................................................................................................................................... 14
Procedure................................................................................................................................................... 17
Variables.................................................................................................................................................... 23
Results........................................................................................................................................................ 24
UV-vis Spectrometry Data...................................................................................................................... 25
Solar Conversion Efficiency Data........................................................................................................... 27
Electron Lifetime Data............................................................................................................................ 38
Incident Photon-to-Current Efficiency (IPCE) Data............................................................................... 43
Discussion and Analysis............................................................................................................................ 46
Conclusion ................................................................................................................................................. 51
Appendix.................................................................................................................................................... 53
Literature Cited ........................................................................................................................................ 57

3. Lee
2
Acknowledgements
First and foremost, I would like to thank William Hoffeditz and Monica So, graduate
students in the department of Chemistry at Northwestern University. William Hoffeditz and
Monica So are both currently completing their Ph.D.’s in Chemistry, and belong to the Hupp
Research Group at Northwestern University. With their guidance and dedication, I was able to
complete a higher-level project than I have in previous years. I would also like to thank Professor
Dick Co of Northwestern University for allowing me to work in his lab and for supporting my
interest in independent research. Additionally, I would like to thank the Argonne-Northwestern
Solar Energy Research (ANSER) Center for providing the funding necessary to complete my
research. I would also like to thank Michael Katz, a Post-Doctoral Fellow at Northwestern
University, for supervising me in the lab whenever Monica and Will were unable. I would also
like to thank my sponsor, Ms. Christine Camel, and my parents for their encouragement and
support.
Special Note
Although Professor Dick Co, Monica So, and William Hoffeditz have been my mentors
and supervisors at Northwestern University, all the data was collected and the entire paper was
written by myself. For Further Inquiry Please Contact:
Dick T. Co, Ph.D.
Director of Operations and Outreach
Research Associate Professor of Chemistry
Department of Chemistry
Northwestern University
2145 Sheridan Road
Evanston, IL 60208-3113
Ph: 847-467-3396;
Fax: 847-467-1425
Email: co@northwestern.edu

4. Lee
3
Purpose
There are two fundamental purposes in which this experiment is based. The first is to
determine the optimal dye loading time of nanoparticles to construct the most efficient dye
sensitized solar cell. The second is to determine the factors that affect solar conversion efficiency,
and how dye structure affects solar cell performance.
Through these studies we will learn how to improve dye sensitized solar cell construction,
and small innovations are necessary to move dye sensitized solar cell technology forward. In order
to become the primary candidate for an alternative fuel source dye sensitized solar cell efficiency
needs to improve to a level that is competitive with silicon solar cells, and eventually fossil fuels.

5. Lee
4
Hypothesis
Hypothesis I:
If dye sensitized solar cells (DSSCs) are dye loaded for 1 hour, 3 hours, 5 hours, and
overnight, then the solar conversion efficiency will increase with increased dye loading time.
Hypothesis II:
If dye sensitized solar cells (DSSCs) are dye loaded with Carbazole, JK2, N719 and
Ru(dcb)(bpy)2 dye, then the extinction coefficient of a given dye will not be the sole factor in
determining solar conversion efficiency.
Hypothesis III:
If dye sensitized solar cells (DSSCs) are dye loaded with Ruthenium and Organic Dyes,
and there are multiple factors affecting solar cell performance, then dye structure will dictate how
electrons travel through the beneficial and parasitic kinetic processes in a dye sensitized solar cell
(DSSC).

6. Lee
5
Review of Literature
Introduction
Global environmental concerns are arising over our excessive reliance on fossil fuels,
which supply most of the world’s electricity (Yum, Chen, Grätzel, & Nazeeruddin, 2008). In
2000, the mean global energy consumption rate was 13 tera watts, which is equivalent to 13
trillion watts (Hagfeldt, A., Boschloo, G., Sun, L., Kloo, L., & Pettersson, H., 2010). These
astonishingly large numbers will only increase in the years to come with the population growth
rate growing exponentially, and in 2050, the projected global consumption rate is 28 tera watts
(28 trillion watts) (Hagfeldt 2010). With these staggering rates of energy consumption that are
only increasing, a number of challenges have arisen such as increasing CO2 , certain countries
having a monopoly over fossil fuel supplies, and environmental implications (Yum 2008). An
alternative fuel source from renewable energy could be the solution to all these problems arising
from excessive use of fossil fuels. Solar energy is an advantageous candidate for an alternative
fuel source because it is low cost, and the sun can sustain the infinitesimally large global energy
consumption rate. However, in order for solar energy to become the prime candidate for an
alternative fuel source efficiency needs to be improved.
Solar Photovoltaics
Solar Photovoltaics are a technology that converts sunlight into electricity through light
absorbing materials connected to an external circuit. To drive excited electrons through an
external circuit, the photovoltaic cell needs to have some asymmetry (Nelson, 2003). The
effectiveness of a photovoltaic device is mainly dependent on the type of light absorbing

7. Lee
6
materials used, and the way in which the light absorbing materials are connected to the external
circuit (Nelson, 2003).
The basic building block of solar photovoltaics is the solar cell (Nelson, 2003). In a
simple electric circuit, the solar cell can take the place of a battery (Nelson, 2003). The open
circuit voltage (Voc) is the voltage developed when the terminals are isolated (infinite load
resistance (Nelson 2003). The open circuit voltage (Voc ) is the maximum voltage available from
a solar cell, and this occurs at zero current. The short circuit current (Jsc) is the maximum current
from the solar cell and occurs when the voltage is zero. The open circuit voltage and short circuit
current are used to determine fill factor. The fill factor (FF) describes the “squareness” of a J - V
Curve (Nelson 2003). The fill factor is defined by the following equation:
The fill factor, short circuit current, and open circuit voltage are used to determine solar energy
conversion efficiency. Solar energy conversion efficiency (η) is the percentage of sunlight
converted to electricity. Solar conversion efficiency is defined by the equation:
Dark current is the current that flows across the device under an implied voltage in the dark
(Nelson 2003). It is important to understand the role that electron density and electron lifetime
(τn) play in photovoltaic performance in order to comprehend the mechanism of dye sensitized
solar cells (DSSCs) (Ito, S., Humphr y-Baker, R., Liska, P., Comte, P., Péchy, P., Nazeeruddin,
M. K., & Grätzel, M., 2011). Electron life measures how many electrons are collected in the
TiO2 conduction band and transferred into current.
(1)
(2)

8. Lee
7
Electron lifetime (τn) is defined by the equation:
where kB is the Boltzmann constant, T is the absolute temperature, q is the positive elementary
charge, and τn is given by the reciprocal of the derivative of the decay normalized by the thermal
voltage (Ito, S., Humphry-Baker, R., Liska, P., Comte, P., Péchy, P., Nazeeruddin, M. K., &
Grätzel, M., 2011). Incident Photon-to-Current Conversion Efficiency is the ratio of the number
of electrons to the number of incident photons collected by the solar cell.
Incident Photon-to-Current Conversion Efficiency (IPCE%) is defined by the equation:
where iph is the photocurrent density generated by monochromatic light with wavelength λ, and
intensity pin.
Dye Sensitized Solar Cells (Third
Generation Solar Cells)
Dye sensitized solar cells are a
fairly new photovoltaic technology as
they were first created in 1991 by
Michael Grätzel, and are regarded as
next generation solar cells because of
their high solar conversion efficiency
and economic benefits (Cheng, Yang,
(3)
Figure 1 Photo of Michael Grätzel, inventor of dye sensitized solar
cells, next to industrial dye sensitized solar cells (Phys.org [online]).
(4)

9. Lee
8
Li, Zhang, & Sun 2013). Dye Sensitized Solar Cells are advantageous for their low productions
costs compared with
conventional photovoltaic
technologies (Hagfeldt 2010).
They are also beneficial for their
flexibility, lightweight,
feedstock availability to reach
terawatt scale, applications for
indoors, ability to capture light
from all angles, and design
opportunities, such as
architectural options. Hagfeldt, A., Boschloo, G., Sun, L., Kloo, L., & Pettersson, H. 2010). A
dye sensitized solar cell is composed of five main components: a conductive mechanical support,
a semiconductor film, a sensitizer, an electrolyte, and a counter electrode. To increase conversion
efficiency, the photosensitizer needs to capture as much incident light as possible (Cheng, Yang,
Li, Zhang, & Sun 2013).
In Figure 2, a schematic representation of the operating principles of the interior of a dye
sensitized solar cell. At the center of a dye sensitized solar cell, is the mesoporous oxide layer
composed of a network of TiO2 nanoparticles that have been sintered together to establish
electronic conduction (Hagfeldt 2010). The mesoporous layer is deposited on a transparent
conducting oxide (TCO) on a glass substrate. Fluorine doped tin oxide (FTO) is a commonly
Figure 2 Schematic of the operating principles of a dye sensitized solar
cell (DSSC).

10. Lee
9
used substrate coated on the glass (Hagfeldt 2010). The charge transfer dye is attached to the
surface of the nanocrystalline film (Hagfeldt 2010).
A dye sensitized solar cell
begins producing electricity once
light hits the dye since it is the
photoactive material of the DSSC
(Dye Sensitized Solar Cells n.d).
The dye produces electricity by
catching photons of incoming
light, and then uses energy to
excite electrons (Dye Sensitized
Solar Cells n.d). Then, the dye injects the excited electrons into the Titanium Dioxide (TiO2),
and the electrolyte closes the cell so that the electrons are returned back to the dye (Dye
Sensitized Solar Cells n.d). The movement of these excited electrons is what creates the energy
that can be harvested into a rechargeable battery, super capacitor or another electrical device
(Dye Sensitized Solar Cells n.d.).
Photosensitizers
The photosensitizer, also known as the dye, is one of the most critical parts of a dye
sensitized solar cell. Some of the key characteristics a dye should fulfill are: 1) have anchoring
groups (-COOH, -H2PO2, -SO3H, etc.) to strongly bind the dye onto the semiconductor surface,
2) have an oxidized state level that is more positive than the redox potential of the electrolyte in
order for dye regeneration to occur, 3) have an absorption spectrum that covers the whole visible
Figure 3 Schematics of the electron transfer processes in a dye sensitized
solar cell (DSSC).

11. Lee
10
region and parts of the near-infrared (NIR), 4) should be photostable, and have electrochemical
and thermal stability (Hagfeldt 2010).
Metal complexes, specifically (Ru(II)) complexes, has shown significant promise because
of their broad absorption spectra and favorable photovoltaic properties (Hagfeldt 2010).
Ruthenium complexes have a relatively long electron lifetime, good electrochemical stability,
suitable excited and ground state energy levels, and broad absorption spectrums (Hagfeldt 2010).
Other than Ruthenium dyes, organic dyes have also gained much popularity among
researchers for their diverse molecular structures that can easily be synthesized and designed,
low cost, and high extinction coefficients (Hagfeldt 2010). Organic dyes with high molecular
extinction coefficients are promising candidates for dye sensitized solar cells because high
molecular extinction coefficients of organic dyes make them ideal absorbers and have
photochemical stability. Organic dyes are also advantageous for their increased open circuit
voltages obtained relative to ruthenium complexes.
Figure 1 demonstrates the molecular structure of the four dyes Carbazole, JK2, N719, and
Ru(dcb)(bpy)2. Carbazole and JK2 are both organic dyes while N719 and Ru(dcb)(bpy)2 are
Ruthenium dyes. Ru(dcb)(bpy)2 is a non-published Ruthenium dye created by William Hoffeditz
at Northwestern University and consists of a carboxyl acid attached to a known Ruthinium
tri(bpy) dye.

12. Lee
11
(a)
(b)
(c)
(d)
Figure 4 Molecular structures of organic and Ruthenium photosensitizers. a) Carbazole. b) JK2. c) N719. d) Ru(dcb)(bpy)2.

13. Lee
12
Electrolyte
Electrolyte containing I-/I3- (iodide) redox ions is used in dye sensitized solar cells to
regenerate the oxidized dye molecules and hence completing the electrical circuit by mediating
electrons between the nanostructured electrode and counter electrode (Kim, J. H., Kang, M. S.,
Kim, Y. J., Won, J., Park, N. G., & Kang, Y. S. 2004). Cell performance is greatly affected by
the ion conductivity of the electrolyte, which is directly affected by the viscosity of the solution
(Kim 2004). Limitations introduced with electrolytes are due to evaporation, liquid electrolyte
inhibits fabrication of multi cell modules, and due to the leakage of the electrolyte from the dye
sensitized solar cell (Kim 2004).
Interfacial Electron-Transfer Kinetics in Metal Free Organic Dye Sensitized Solar Cells:
Combined Effects of Molecular Structure of Dyes and Electrolytes
An experiment called Interfacial Electron-Transfer Kinetics in Metal Free Organic Dye
Sensitized Solar Cells: Combined Effects of Molecular Structure of Dyes and Electrolytes studied
electron diffusion coefficient, lifetime, and density in the TiO2 electrode of dye sensitized solar
cells (Miyashita, M., Sunahara, K., Nishikawa, T., Uemura, Y., Koumura, N., Hara, K., ... &
Mori, S. 2008). They compared the efficiencies of 8 organic dyes and 3 Ruthenium dyes. The
results demonstrated that organic dyes have a longer lifetime when they have larger molecular
size and alkyl chains which leads to a higher short circuit current. Although, none of the organic
dyes had longer lifetimes than the Ruthenium dyes (Miyashita 2008).
Closure
As global environmental concerns increase, and the supply of fossil fuels is rapidly
dwindling the importance of researching alternative fuel sources could never be of more utmost

14. Lee
13
importance. Dye sensitized solar cells have the potential to become a prime candidate for an
alternative fuel source due to their low production costs and high conversion efficiencies (Yum
2008). Compared to silicon based solar cells, dye sensitized solar cells are of low cost and ease
of production, have an increased performance with temperature, and possess a bifacial
configuration as they have an advantage for diffuse light, transparency for power windows,
varied color from dye, and outperform silicon solar cells in light and cloudy conditions (Yum
2008). The highest solar conversion achieved by a dye sensitized solar cell is over 11%, and was
constructed with a Ruthenium based dye, TiO2 electrode, and an iodide electrolyte (Miyashita
2008). Small modifications that improve individual components such as improving the short
circuit current density, open circuit voltage, and fill factor by extending the light response of the
sensitizers in the near-infrared spectral region, introducing ordered oxide mesostructures and
controlling the interfacial charge recombination by manipulating the cell on the molecular level
are necessary to improve overall efficiency.

15. Lee
14
Materials
Nanocrystalline TiO2 Electrode
 Flourine Doped Tin Oxide (FTO)
 Glass Cutter
 Scribe
 Pliers
 Dog Dish
 Sonicator
 Alconox
 Deionized Water
 EtOH
 UV-O3
 Atomic Layer Deposition
 TiO2
 Nanoparticles
 Scotch Brand Tape
 Hole Puncher
 Stainless Steel Razor Blade
 Dyesol Transparent Terpineol Paste
 Oven
Dye Chemicals and Materials
 5.6 mg of Carbazole
 5.4 mg of JK2
 5.3 mg of Ru(dcb)(bpy)2
 5.4 mg of N719
 Chloroform
 Tetrahydrofuran
 Acetonitrile
 Ethanol
 Lab Balance
 Plastic Square Dishes
 Stainless Steel Tweezers
 Permanent Marker

16. Lee
15
UV-vis Spectrometry
 0.458 M Carbazole Dye
 0.732 M JK2 Dye
 0.454 M N719 Dye
 0.561 M Ru(dcb)(bpy)2 Dye
 Automatic Pipettes
 Glass Screw Bottles
 Glass Beakers
 Cuvette
 Spectrometer
 Chemical Wipes
 Computer (Excel)
Dye Loading
 0.5 mM Carbazole dye
 0.5 mM JK2 dye
 0.5 mM N719 dye
 0.5 mM Ru(dcb)(bpy)2 dye
 Stainless Steel Tweezers
 Glass Screw Bottles
Pt Electrode
 Drill
 F-SnO2
 0.1 M HCl
 EtOH
 Acetone
 Isopropanol
 Ethanol
 5 mM H2PtCl-6
Dye Sensitized Solar Cell Assembly
 25 um Ionomer Surlyn 1702 (Dupont)
 TiO2
 Hot Plate
 Plastic Tweezers
 Hydrogen Gas Pump

17. Lee
16
 Sandpaper
 F-SnO2 Electrodes
 Silver Epoxy Paste
 Tin Wires
 Oven
 Stainless Steel Tweezers
 Iodide/Triiodide (I3
/I-
) Electrolyte
 Glass Cover Slides
 Soldering Iron
 Vacuum Desiccator
 Chemical Wipes
 Hydrogen Gas Pump
Measuring Dye Sensitized Solar Cells
 Potentiostat
 Computer (Excel)
General Safety Materials
 Goggles
 Plastic Gloves
 Lab Coat
 Close Toed Shoes
 Pants
**No Skin May be Exposed while Performing the Experiment**

18. Lee
17
Procedure
Nanocrystalline-TiO2 Electrode
1. A full sheet of Fluorine Doped Tin oxide (FTO) glass was cut into 0.25 cm2
squares using
a glass cutter, pliers, and scribe.
2. Fluorine Doped Tin oxide (FTO) glass squares were then washed in a dog dish using
Alconox soap and deionized water.
3. After the Fluorine Doped Tin oxide (FTO) glass squares were washed, they were sonicated
for 25 minutes, and rinsed with water and EtOH, and treated with UV-O3 treatment for 18
minutes.
4. A blocking layer of TiO2 must be created by an Atomic Layer Deposition (ALD).
5. To place nanoparticles, Scotch brand tape was first hole punched to achieve an electrode
area of 5mm x 5mm.
6. Fluorine Doped Tin oxide (FTO) glass squares were then placed on a glass sheet evenly
spaced in rows, and held in place with the hole punched Scotch brand tape.
7. Dyesol purchased transparent terpineol paste was placed on the edge of the holes and
excess was doctor bladed with a razor blade in one smooth quick movement.
8. After approximately three minutes, the tape was removed and the Fluorine Doped Tin
oxide (FTO) glass squares were dried in a drying oven for six minutes at 125o
C.
9. The cells were then gradually heated at 325ºC for 5 minutes, 375ºC for 5 minutes, 450º C
for 15 minutes.

19. Lee
18
Dyes
1. Dissolved 5.6 mg of Carbazole in
chloroform to achieve a 0.458 M
solution of Carbazole Dye.
2. Dissolved 5.4 mg of JK2 in
tetrahydrofuran to achieve a 0.732
M solution of JK2 dye.
3. Dissolved 5.3 mg of Ru(dcb)(bpy)2
in acetonitrile to achieve a 0.561 M solution of Ru(dcb)(bpy)2 dye.
4. Dissolved 5.4 mg of N719 in ethanol to achieve a 0.454 M solution of N719 Dye.
5. The stock for each of the 4 dyes was diluted in ratios of 1 to 10, 1 to 20, 1 to 30, 1 to 40,
and 1 to 50 to obtain 5 points for UV-vis measurements.
6. For each dye, absorbance was plotted as a function of concentration to determine the
wavelength in which the peak absorbance was reached.
7. Extinction coefficients were calculated by finding the slope of the points in an Absorbance
vs Concentration at the peak wavelength plot.
Dye Loading
1. After cooling to 80ºC immerse electrode in 0.5 mM of either Carbazole, JK2, N719, or
Ru(dcb)bpy in 1:1 acetonitrile:tert-
butyl alcohol (EtOH also works)
and kept at room temp in time
Figure 5 Ru(dcb)(bpy)2 dye solution, N719 dye solution, JK2 dye
solution, and Carbazole dye solution used to dye load dye sensitized
solar cells.
Figure 6 Dye loaded dye sensitized solar cells with Ru(dcb)(bpy)2,
N719, Carbazole, and JK2 dyes.

20. Lee
19
increments of either 1, 3, 5, or 24 hours. Dye solution should be sonicated and filtered to
ensure solution is fully saturated.
2. Remove electrode from solution and quickly rinse with acetonitrile. Dry under H2 stream.
Pt Electrode
1. For the Pt electrode, a hole was drilled in 15ohm/sq F-SnO2, and then sonicated in soap.
2. F-SnO2 was the washed with water and 0.1M HCl solution in EtOH (~1 mL conc. HCl in
100ml) and sonicated in acetone bath for 10 minutes.
3. Residual organic contaminants were removed by heating in air for 15 min at 400ºC.
4. Pt catalyst was deposited by coating with a ~0.5 drop/cm2 of 5mM H2PtCl¬6 in
isopropanol (or ethanol). They were then quickly tilted to
spread and let dry without breeze for 5 minutes.
Solar Cell Assembly
1. To assemble the cells, they were first sandwiched with 25
um ionomer Surlyn 1702 (Dupont) between electrodes.
The aperature should be 2 mm larger than that of TiO2
area and width of 1mm.
2. To sandwich the cells, the sample was first aligned such
that electrolyte hole was not directly over active area.
Figure 7 A dye sensitized solar cell
sandwiched with surlyn.

21. Lee
20
3. Then, once the cells were aligned correctly over the
electrolyte hole, the cells were put on a hot plate at 130ºC for
3-5 minutes while significant pressure was applied with
tweezers to seal the cells.
4. Sandpaper was then used to lightly scrape the edge of F-SnO2
electrodes.
5. Distance is importance as sheet resistance is an issue but it is
crucial not to short the cell by connecting electrodes! Epoxy
must then be mixed in equal ratios and stirrer for 2 minutes.
6. Silver epoxy and wires were then applied to both sides of the
cells, and the cells were then placed in the oven for 15-25 minutes at 100ºC.
7. Silver epoxy and wires were then applied to both sides of the cells,
and the cells were then placed in the oven for 15-25 minutes at
100ºC.
8. Iodide electrolyte was then prepared, and the electrolyte solution
was placed in excess to cover the hole in the cells.
9. The cells were then placed in a vacuum desiccator to draw the
electrolyte into the TiO2 network.
10. To seal the hole, surlyn and cover glass was soldered at 600ºF
with a soldering iron to quickly melt polymer film without dumping excess heat into
volatile electrolyte.
Figure 8 Epoxy paste used for
experiment.
Figure 9 A dye sensitized
solar cell sealed with
electrolyte.

22. Lee
21
Measuring
1. A potentiostat was used to take voltage, and
current measurements to make JV curves of
light current and dark currents, and Incident
Photon-to-Current Conversion Efficiency
(IPCE), and electron lifetime plots for the
Dye Sensitized Solar Cells (DSSCs).
2. When taking potentiostat measurements
light intensity was set to 0.2 sun. All
samples required the light switched on then off while measuring photovoltage.
3. The potentiostat was set to collect photovoltage measurements for every 0.001 seconds
over a span 15 seconds (about 25,000 data points collected per solar cell).
Data Calculations
1. Potentiostat will give current and voltage values, and the current density and fill factor
must be calculated for JV curves.
2. Current density was calculated by dividing current by the area of the solar cell (0.25 cm2
)
and multiplying that by negative 1,000.
Figure 10 Potentiostat taking measurements from a dye
sensitized solar cell exposed to white light.

23. Lee
22
3. Fill factor was calculated by multiplying current density
and voltage and dividing that by the product of the Jsc and
Voc, which were identified by finding the maximums of
the current density and voltage measurements produced
from the solar cell.
4. Efficiency was calculated by multiplying the fill factor, Jsc
and Voc.
5. Photovoltage decay was determined by finding the data
points after the light was turned off and imputing it into
the following equation:
6. Incident Photon-to-Electron conversion Efficiency (IPCE)
was calculated by the following equation:
7. The ratio of backside Incident Photon-to-Electron conversion Efficiency (IPCE) to front
side was then calculated for data analysis comparison.
Figure 11 Potentiostat taking
measurements from a dye sensitized
solar cell exposed to white light.

24. Lee
23
Variables
Independent Variables: Type of Dye (Carbazole, JK2, N719, and Ru(dcb)(bpy)2), and Dye
Loading Time of Nanoparticles (1 Hour, 3 Hours, 5 Hours, and 24 Hours).
Dependent Variables: UV-vis Spectrometry will be used to determine extinction coefficients of
Carbazole, JK2, N719, and Ru(dcb)(bpy)2 and their respective absorption spectra. J-V Curves will
be used to determine short circuit current (Jsc), open circuit voltage (Voc), fill factor (FF), and
solar conversion efficiency for each dye sensitized solar cell (DSSC). Electron lifetime plots will
be used to determine photovoltage decay of each dye, and the rate in which electrons are collected
by the TiO2 conduction band and transformed to current. Incident photon-to-current conversion
efficiency (IPCE) will be used to determine how well the dyes can collect photons of light.
Control: Not applicable for this experiment and a comparison will be made among trial groups.
Controlled Variables: Experimenter, procedures followed, area of dye sensitized solar cells (0.25
cm2
), type of light used (White Light), type of electrolyte used (I3
/I-
), type of glass (Fluorine Doped
Tin Oxide), type of blocking layer (Nanocrystalline Titanium Dioxide), location of equipment used
(for Dye Sensitized Solar Cell (DSSC) construction, UV-Vis Spectrometry, JV Curves, Electron
Lifetime, and Incident Photon-to-Current Conversion Efficiency (IPCE)), equipment location, and
software used for data analyses.

25. Lee
24
Results
UV-vis Spectrometry Data ..........................................................................................................25
Solar Conversion Efficiency Data...............................................................................................27
Electron Lifetime Data ................................................................................................................38
Incident Photon-to-Current Conversion Efficiency (IPCE) Data...........................................43

26. Lee
25
UV-vis Spectrometry Data
The absorption spectra for
Carbazole, in figure 13, demonstrates
that light is most absorbed from 480 nm
to 510 nm. The total range of wavelength
where Carbazole absorbs light is from
400 nm to 600 nm, and almost
no light is absorbed at 650 nm.
The extinction coefficient for
the Carbazole dye is 44,817 M-
1
cm-1
and the Beer’s law plot
had an R2
value of 0.9991. The
R2
value suggests that the linear
model of best fit represents
99.91% of the variation in the
data.
Dyes Molar Extinction
Coefficient (M-1
cm-1
)
Carbazole 44,817
JK2 27,380
N719 14,007
Ru(dcb)(bpy)2 12,142
0
0.5
1
1.5
2
2.5
400 450 500 550 600 650 700 750 800
Absorbance(Arb.Units)
Wavelength (nm)
JK2 1 to 50 JK2 1 to 30 JK2 1 to 40 JK2 1 to 20 JK2 1 to 10
Table 12 Extinction coefficients of the four
dyes (Carbazole, JK2, N719, Ru(dcb)(bpy)2).
Values are extrapolated from Figure 1,
Figure, 2, Figure 3 and Figure 4.
y = 27380x + 0.0697
R² = 0.9984
0
0.5
1
1.5
2
2.5
0.00E+00 5.00E-05 1.00E-04
Absorbance(Arb.Units)
Concentration (M)
Figure 14 UV-Vis absorption spectra of JK2 dye. Dilutions were taken from the stock
solution in ratios of 1 to 10, 1 to 20, 1 to 30, 1 to 40, and 1 to 50. The wavelength with
peak absorbance for all dilutions was plotted in a Beer’s Law plot over concentration
and the slope of that plot denotes the extinction coefficient. The peak absorbance for the
JK2 dye were all found at 481 nm.
.
Figure 13 UV-Vis absorption spectra of Carbazole dye. Dilutions were
taken from the stock solution in ratios of 1 to 10, 1 to 20, 1 to 40, and 1
to 50. The wavelength with peak absorbance for all dilutions was
plotted in a Beer’s Law plot over concentration and the slope of that plot
denotes the extinction coefficient. The peak absorbance for the
Carbazole dye were all found at 485 nm.
0
0.5
1
1.5
2
400 500 600 700 800
Absorbance(Arb.Units)
Wavelength (nm)
Carbz 1 to 10
Carbz 1 to 60
Carbz 1 to 40
Carbz 1 to 20
y = 44817x - 0.0215
R² = 0.9991
0
0.5
1
1.5
2
2.5
0.00E+002.00E-054.00E-056.00E-05
Absorbance(Arb.Units)
Concentration (M)

27. Lee
26
The absorption spectra for JK2, in figure 14, demonstrates that light is most absorbed from
450 nm to 510 nm for dye sensitized solar cells dye loaded with JK2 dye. The total range of
wavelength where JK2 absorbs light is from 400 nm to 580 nm, and almost no light is absorbed at
600 nm. The extinction coefficient for the JK2 dye is 27,380 M-1
cm-1
and the Beer’s law plot had
an R2
value of 0.9984. The R2
value suggests that the linear model of best fit represents 99.84% of
the variation in the data.
The absorption spectra for N719, in figure 15, demonstrates that light is most absorbed
from 500 nm to 550 nm for dye sensitized solar cells dye loaded with N719 dye. The total range
of wavelength where
N719 absorbs light is
from 400 nm to 720 nm,
and almost no light is
absorbed at 750 nm. The
extinction coefficient for
the N719 dye is 14,007
M-1
cm-1
, and the Beer’s
law plot had an R2
value
of 0.9999. The R2
value
suggests that the linear
model of best fit
represents 99.99% of the
variation in the data.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
400 450 500 550 600 650 700 750 800
AbsorbanceArbitraryUnits
Wavelength (nm)
N719 1 to 5 N719 1 to 10 N719 1 to 20 N719 1 to 50
y = 14007x + 0.0256
R² = 0.9999
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0.00E+00 5.00E-05 1.00E-04
Absorbance(Arb.Units)
Concentration (M)
Figure 15 UV-Vis absorption spectra of N719 dye. Dilutions were taken from the stock
solution in ratios of 1 to 5, 1 to 10, 1 to 20, and 1 to 50. The wavelength with peak
absorbance for all dilutions was plotted in a Beer’s Law plot over concentration and the
slope of that plot denotes the extinction coefficient. The peak absorbance for the N719
dye were all found at 528 nm.
.

28. Lee
27
The absorption
spectra for Ru(dcb)(bpy)2,
in figure 16, demonstrates
that light is most absorbed
from 420 nm to 490 nm
for dye sensitized solar
cells dye loaded with
Ru(dcb)(bpy)2 dye. The
total range of wavelength
where Ru(dcb)(bpy)2 dye
absorbs light is from 400 nm to
600 nm, and almost no light is
absorbed at 640 nm. The extinction coefficient for the Ru(dcb)(bpy)2 dye is 12,142 M-1
cm-1
and
the Beer’s law plot had an R2
value of 0.9986. The R2
value suggests that the linear model of best
fit represents 99.86% of the variation in the data.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
400 450 500 550 600 650 700 750 800
Absorbance(ArbitraryUnits)
Wavelength (nm)
Ru(dbc)bpy 1 to 40 Ru(dbc)bpy 1 to 20
Ru(dbc)bpy 1 to 10 Ru(dcb)bpy 1 to 5
y = 12142x + 0.0012
R² = 0.9986
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0.00E+00 5.00E-05 1.00E-04 1.50E-04
Absorobance(Arb.Units)
Concentration (M)
Figure 16 UV-Vis absorption spectra of Ru(dcb)(bpy) dye. Dilutions were taken
from the stock solution in ratios of 1 to 5, 1 to 10, 1 to 20, and 1 to 40. The
wavelength with peak absorbance for all dilutions was plotted in a Beer’s Law plot
over concentration and the slope of that plot denotes the extinction coefficient. The
peak absorbance for the Ru(dcb)bpy dye were all found at 476 nm.
.

29. Lee
28
Solar Conversion Efficiency Data
Carbazole DSSCs with Highest Efficiency
Cell Type Jsc (mA/cm2
) Voc (V) Fill Factor Efficiency (%)
1 Hour Cell 3 2.607 0.603 0.734 1.152
1 Hour Cell 3 Dark Current -4.08E-04 -0.089 0.323 1.17E-05
3 Hour Cell 1 4.592 0.610 0.725 2.028
3 Hour Cell 1 Dark Current -3.43E-04 -0.084 0.412 1.18E-05
5 Hour Cell 1 5.833 0.615 0.739 2.646
5 Hour Cell 1 Dark Current -0.0004 -0.048 0.947 1.67E-05
24 Hour Cell 1 3.404 0.594 0.697 1.407
24 Hour Cell 1 Dark Current -0.0004 -0.082 0.423 1.32E-05
JK2 DSSCs with Highest Efficiency
Cell Type Jsc (mA/cm2
) Voc (V) Fill Factor Efficiency (%)
1 Hour Cell 3 0.950 0.571 0.730 0.396
1 Hour Cell 3 Dark Current -0.0008 -0.088 0.339 2.29E-05
3 Hour Cell 3 0.764 0.547 0.764 0.320
3 Hour Cell 3 Dark Current -0.0004 -0.083 0.483 1.26E-05
5 Hour Cell 1 0.5418 0.596 0.590 0.190
5 Hour Cell 1 Dark Current -0.0004 -0.088 0.510 1.64E-05
Overnight Cell 1 0.586 0.561 0.751 0.247
Overnight Cell 1 Dark Current -0.0004 -0.075 0.425 1.20E-05
Table 2 Best solar energy conversion efficiencies for Carbazole DSSCs fabricated with time dependent dye loading.
Table 3 Best solar energy conversion efficiencies for JK2 DSSCs fabricated with time dependent dye loading.

30. Lee
29
Ru(dcb)(bpy)2 DSSCs with High Efficiency
Cell Type Jsc (mA/cm2
) Voc (V) Fill Factor Efficiency (%)
1 Hour Cell 3 1.173 0.573 0.781 0.525
1 Hour Cell 3 Dark Current -0.0006 -0.068 0.304 1.16E-05
3 Hour Cell 2 0.475 0.510 0.760 0.184
3 Hour Cell 2 Dark Current -0.0003 -0.083 0.449 1.18E-05
5 Hour Cell 1 1.165 0.556 0.698 0.452185
5 Hour Cell 1 Dark Current -0.0005 -0.042 0.346 6.52E-06
Overnight Cell 2 0.567 0.510 0.751 0.217
Overnight Cell 2 Dark Current -0.0006 -0.030 0.153 2.56E-06
N719 DSSCs with Highest Efficiency
Cell Type Jsc
(mA/cm2
)
Voc (V) Fill
Factor
Efficiency
(%)
1 Hour Cell 2 3.833 0.683 0.653 1.710
1 Hour Cell 2 Dark Current -0.0004 -0.057 0.603 1.32E-05
3 Hour Cell 2 Darker 4.409 0.667 0.461 1.357
3 Hour Cell 2 Dark Current -0.0003 -0.079 0.394 1.06E-05
5 Hour Cell 1 4.574 0.664 0.764 2.322
5 Hour Cell 1 Dark Current -0.0004 -0.079 0.453 1.36E-05
Overnight Cell 4 3.791 0.681 0.796 2.056
Overnight Cell 4 Dark Current -0.00082 -0.083 0.261 1.77E-05
Table 4 Best solar energy conversion efficiencies for N719 DSSCs fabricated with time dependent dye loading.
Table 5 Best solar energy conversion efficiencies for Ru(dcb)(bpy)2 DSSCs fabricated with time dependent dye loading.

31. Lee
30
Figure 17 shows the photocurrent-voltage curves and the respective dark currents of the
best cells dye loaded
with carbazole dye. A
dye sensitized solar
cell dye loaded for 1
hour with carbazole
dye had a short circuit
current density of 2.61
mA/cm2
, an open
circuit voltage of 0.60
V, and a fill factor of
0.73. The power
conversion efficiency
achieved was 1.15%. The dark current for the carbazole dye sensitized solar cell dye loaded for 1
hour had a short circuit current of -4.08E-4 mA/cm2
, an open circuit voltage of -0.09 V, and a fill
factor of 0.32. The power conversion efficiency achieved was 1.17E-5%. The carbazole dye
sensitized solar cell dye loaded for 1 hour had the lowest efficiency compared to the 3 hour, 5
hour, and overnight carbazole dye loaded solar cells. A dye sensitized solar cell dye loaded for 3
hours with carbazole dye had a short circuit current density of 4.59 mA/cm2
, an open circuit voltage
of 0.61 V, and a fill factor of 0.72. The power conversion efficiency produced was 2.03%, and this
was the second highest efficiency produced by the carbazole dye. The dark current for the
carbazole dye sensitized solar cell dye loaded for 3 hour had a short circuit current of -3.43E-4
-1
0
1
2
3
4
5
6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
CurrentDensity(mA/cm2)
Voltage (V)
1 Hour Cell 3
1 Hour Cell 3
Dark Current
3 Hour Cell 1
3 Hour Cell 1
Dark Current
5 Hour Cell 1
5 Hour Cell 1
Dark Current
Overnight Cell 1
Overnight Cell 1
Dark Current
Figure 17 The photocurrent-voltage curves and the respective dark currents (DC) on
the DSSCs dye loaded with carbazole dye at four different time increments 1 hour, 3
hour, 5 hour, and overnight.

32. Lee
31
mA/cm2, an open circuit voltage of -0.08 V, and a fill factor of 0.41. The power conversion
efficiency achieved was 1.18E-5%. On the other hand, a dye sensitized solar cell dye loaded for 5
hours produced an efficiency of 2.65%, which happens to be the highest overall efficiency out of
all of the dyes. The dark current for the carbazole dye sensitized solar cell dye loaded for 5 hour
had a short circuit current of -3.70E-4 mA/cm2
, an open circuit voltage of -0.048 V, and a fill factor
of 0.95. The power conversion efficiency achieved was 1.67E-5%. A dye sensitized solar cell dye
loaded for 24 hours with carbazole dye had a short circuit current density of 3.40 mA/cm2, an open
circuit voltage of 0.59 V, and a fill factor of 0.69. The power conversion efficiency achieved was
1.41%. The dark current for the carbazole dye sensitized solar cell dye loaded for 24 hours had a
short circuit current
of -3.80E-4 mA/cm2,
an open circuit
voltage of -0.08 V,
and a fill factor of
0.42. The power
conversion
efficiency achieved
was 1.32E-5%.
Figure 18
shows the
photocurrent-voltage
curves and the respective
Figure 18 The photocurrent-voltage curves and the respective dark currents (DC) on
the DSSCs dye loaded with JK2 dye at four different time increments 1 hour, 3 hours,
5 hours, and 24 hours.
-0.1
0.1
0.3
0.5
0.7
0.9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
CurrentDensity(mA/cm2)
Voltage (V)
1 Hour Cell 2
1 Hour Cell 2 DC
3 Hour Cell 2
3 Hour Cell 2 DC
5 Hour Cell 1
5 Hour Cell 1 DC
24 Hour Cell 1
24 Hours Cell 1
DC

33. Lee
32
dark currents of the best cells dye loaded with JK2 dye. A dye sensitized solar cell dye loaded for
1 hour with JK2 dye had a short circuit current density of 1.16 mA/cm2
, an open circuit voltage of
0.53 V, and a fill factor of 0.65. The power conversion efficiency achieved was 0.05%. The dark
current for the JK2 sensitized solar cell dye loaded for 1 hour had a short circuit current of -3.92E-
4 mA/cm2
, an open circuit voltage of -0.04 V, and a fill factor of 0.21. The power conversion
efficiency achieved was 3.73E-6%. A dye sensitized solar cell dye loaded for 3 hours with JK2
dye had a short circuit current density of 0.20 mA/cm2
, an open circuit voltage of 0.50 V, and a
fill factor of 0.60. The power conversion efficiency achieved was 0.06%. The dark current for the
JK2 sensitized solar cell dye loaded for 3 hours had a short circuit current of -0.06 mA/cm2
, an
open circuit voltage of -0.04 V, and a fill factor of 0.21. The power conversion efficiency achieved
was 3.73E-6%. A dye sensitized solar cell dye loaded for 5 hours with JK2 dye had a short circuit
current density of 5.83 mA/cm2
, an open circuit voltage of 0.61 V, and a fill factor of 0.74. The
power conversion efficiency achieved was 2.65%. The dark current for the JK2 sensitized solar
cell dye loaded for 5 hours had a short circuit current of -3.7E-4 mA/cm2
, an open circuit voltage
of -0.09 V, and a fill factor of 0.51. The power conversion efficiency achieved was 1.64E-5%. A
dye sensitized solar cell dye loaded for 24 hours with JK2 dye had a short circuit current density
of 0.59 mA/cm2
, an open circuit voltage of 0.56 V, and a fill factor of 0.75. The power conversion
efficiency achieved was 0.25%, which was the overall best efficiency for the cells dye loaded with
JK2 dye. The dark current for the JK2 sensitized solar cell dye loaded for 24 hours had a short
circuit current of -3.8E-4 mA/cm2
, an open circuit voltage of -0.08 V, and a fill factor of 0.43. The
power conversion efficiency achieved was 1.20E-5%.

34. Lee
33
Figure 19 shows the photocurrent-voltage curves and the respective dark currents of the
best cells dye loaded with N719 dye. A dye sensitized solar cell dye loaded for 1 hour with N719
dye had a short
circuit current
density of 3.83
mA/cm2
, an open
circuit voltage of
0.68 V, and a fill
factor of 0.65. The
power conversion
efficiency
achieved was
1.71%. The dark
current for the N719
sensitized solar cell dye loaded for 1 hour had a short circuit current of -3.8E-4 mA/cm2
, an open
circuit voltage of -0.06 V, and a fill factor of 0.60. The power conversion efficiency achieved was
1.32E-5%. A dye sensitized solar cell dye loaded for 3 hours with N719 dye had a short circuit
current density of 4.41 mA/cm2
, an open circuit voltage of 0.67 V, and a fill factor of 0.46. The
power conversion efficiency achieved was 1.36%. The dark current for the N719 sensitized solar
cell dye loaded for 3 hours had a short circuit current of -3.4E-4 mA/cm2
, an open circuit voltage
of -0.08 V, and a fill factor of 0.39. The power conversion efficiency achieved was 1.06E-5%. A
dye sensitized solar cell dye loaded for 5 hours with N719 dye had a short circuit current density
-0.1
0.4
0.9
1.4
1.9
2.4
2.9
3.4
3.9
4.4
0 0.2 0.4 0.6 0.8
CurrentDensity(mA/cm2)
Voltage (V)
1 Hour Cell 2
1 Hour Cell 2 DC
3 Hour Cell 2
3 Hour Cell 2 DC
5 Hour Cell 1
5 Hour Cell 1 DC
24 Hour Cell 4
24 Hour Cell 4
DC
Figure 19 The photocurrent-voltage curves and the respective dark currents (DC) on
the DSSCs dye loaded with N719 dye at four different time increments 1 hour, 3 hours,
5 hours, and 24 hours.

35. Lee
34
of 4.57 mA/cm2
, an open circuit voltage of 0.66 V, and a fill factor of 0.76. The power conversion
efficiency achieved was 2.32%, which was the overall best power conversion efficiency for the
N719 dye sensitized solar cells. The dark current for the N719 sensitized solar cell dye loaded for
5 hours had a short circuit current of -3.8E-4 mA/cm2
, an open circuit voltage of -0.08 V, and a
fill factor of 0.45. The power conversion efficiency achieved was 1.36E-5%. A dye sensitized solar
cell dye loaded for 24 hours with N719 dye had a short circuit current density of 4.56 mA/cm2
, an
open circuit voltage of 0.62 V, and a fill factor of 0.52. The power conversion efficiency achieved
was 1.47%. The dark current for the N719 sensitized solar cell dye loaded for 24 hours had a short
circuit current of -8.2E-3 mA/cm2
, an open circuit voltage of -0.0024 V, and a fill factor of 0.38.
The power conversion
efficiency achieved was
-7.41E-6%.
Figure 20 shows
the photocurrent-
voltage curves and the
respective dark currents
of the best cells dye
loaded with Ru(bpy)2
dye. A dye sensitized
solar cell dye loaded for
1 hour with Ru(bpy)2 dye had a
short circuit current density of 1. 17 mA/cm2
, an open circuit voltage of 0.57 V, and a fill factor of
-0.1
0.1
0.3
0.5
0.7
0.9
1.1
1.3
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
CurrentDensity(mA/cm2)
Voltage (V)
1 Hour Cell 3
1 Hour Cell 3 DC
3 Hour Cell 2
3 Hour Cell 2 DC
5 Hour Cell 1
5 Hour Cell 1 DC
24 Hour Cell 2
24 Hour Cell 2
DC
Figure 20 The photocurrent-voltage curves and the respective dark currents (DC)
for the DSSCs with the dye loaded with Ru(dcb)(bpy)2 dye at four different time
increments 1 hour, 3 hours, 5 hours, and 24 hours.

36. Lee
35
0.78. The power conversion efficiency achieved was 0.52%. The dark current for the
Ru(dcb)(bpy)2 dye sensitized solar cell dye loaded for 1 hour had a short circuit current of -5.56E-
4 mA/cm2
, an open circuit voltage of -0.07 V, and a fill factor of 0.30. The power conversion
efficiency achieved was 1.16E-5%. A dye sensitized solar cell dye loaded for 3 hours with
Ru(dcb)(bpy)2 dye had a short circuit current density of 0.47 mA/cm2
, an open circuit voltage of
0.51 V, and a fill factor of 0.76. The power conversion efficiency achieved was 0.18%. The dark
current for the Ru(dcb)(bpy)2 dye sensitized solar cell dye loaded for 3 hours had a short circuit
current of -3.17E-4 mA/cm2
, an open circuit voltage of -0.08 V, and a fill factor of 0.45. The power
conversion efficiency achieved was 1.18E-5%. A dye sensitized solar cell dye loaded for 5 hours
with Ru(dcb)(bpy)2 dye had a short circuit current density of 1.17 mA/cm2
, an open circuit voltage
of 0.56 V, and a fill factor of 0.70. The power conversion efficiency achieved was 0.45%. The
dark current for the Ru(dcb)(bpy)2 dye sensitized solar cell dye loaded for 5 hours had a short
circuit current of -4.46E-4 mA/cm2
, an open circuit voltage of -0.04 V, and a fill factor of 0.35.
The power conversion efficiency achieved was 6.52E-6%. A dye sensitized solar cell dye loaded
for 24 hours with Ru(dcb)(bpy)2 dye had a short circuit current density of 0.57 mA/cm2
, an open
circuit voltage of 0.51 V, and a fill factor of 0.75. The power conversion efficiency achieved was
0.21%. The dark current for the Ru(dcb)(bpy)2 dye sensitized solar cell dye loaded for 24 hours

37. Lee
36
had a short circuit current of -5.70E-4 mA/cm2
, an open circuit voltage of -0.02 V, and a fill factor
of 0.15. The power conversion efficiency achieved was 2.56E-6%.
Figure 21 shows the photocurrent-voltage curves and the respective dark currents of the
best cells dye loaded with Carbazole, JK2, N719, and Ru(dcb)(bpy)2 dye. The best performing dye
sensitized solar cell constructed with Carbazole dye was dye loaded for 5 hours. It had a short
circuit current density of
5.83 mA/cm2
, an open
circuit voltage of 0.61
V, and a fill factor of
0.74. The power
conversion efficiency
achieved was 2.65%.
The dark current for the
Carbazoledye sensitized
solar cell dye loaded for
5 hours had a short
circuit current of -4.76E-2
mA/cm2
, an open circuit
voltage of 0.95 V, and a fill factor of 0.30. The power conversion efficiency achieved was 1.67E-
5%.
The best performing dye sensitized solar cell dye loaded with JK2 dye for 1 hour. It had a
short circuit current density of 0.95 mA/cm2
, an open circuit voltage of 0.57 V, and a fill factor of
-1
0
1
2
3
4
5
6
0 0.2 0.4 0.6 0.8 1
CurrentDensity(mA/cm2)
Voltage (V)
Carbazole 5 Hour 1
Carbazole 5 Hour
Cell 1 Dark Current
JK2 1 Hour Cell 3
JK2 1 Hour Cell 3
Dark Current
N719 5 Hour Cell 1
N719 5 Hour Cell 1
Dark Current
Ru(dcb)bpy 1 Hour
Cell 3
Ru(dcb)bpy 1 Hour
Cell 3 Dark Current
Figure 21 The photocurrent-voltage curves and the respective dark currents (DC) for
the DSSCs with the highest efficiencies dye loaded with Carbazole, JK2, N719, and
Ru(dcb)(bpy)2 dye at four different time increments 1 hour, 3 hours, 5 hours, and 24
hours.

38. Lee
37
0.73. The power conversion efficiency achieved was 0.39%. The dark current for the JK2 dye
sensitized solar cell dye loaded for 5 hours had a short circuit current of -7.72E-4 mA/cm2
, an open
circuit voltage of -0.09 V, and a fill factor of 0.34. The power conversion efficiency achieved was
2.29E-5%.
The best performing dye sensitized solar cell constructed with N719 dye was dye loaded
for 5 hours. It had a short circuit current density of 4.57 mA/cm2
, an open circuit voltage of 0.66
V, and a fill factor of 0.76. The power conversion efficiency achieved was 2.32%. The dark current
for the N719 dye sensitized solar cell dye loaded for 5 hours had a short circuit current of -7.78E-
2 mA/cm2
, an open circuit voltage of 0.45 V, and a fill factor of 0.45. The power conversion
efficiency achieved was 1.36E-5%.
The best performing dye sensitized solar cell dye loaded with Ru(dcb)bpy dye for 1 hour
had a short circuit current density of 1.17 mA/cm2
, an open circuit voltage of 0.57 V, and a fill
factor of 0.78. The power conversion efficiency achieved was 0.52%. The dark current for the
Ru(dcb)(bpy)2 dye sensitized solar cell dye loaded for 5 hours had a short circuit current of -4.76E-
2 mA/cm2
, an open circuit voltage of 0.95 V, and a fill factor of 0.30. The power conversion
efficiency achieved was 1.67E-5%.
Overall, Carbazole produced the DSSC with the highest efficiency of 2.64%. However,
N719 produced the highest open circuit voltage of 0.66 V, and the highest fill factor was produced
by Ru(dcb)(bpy)2 which was 0.78.

39. Lee
38
Electron Lifetime Data
Figure 22 shows
the charge lifetime for the
dye sensitized solar cells
with the highest short
circuit currents (Jsc) that
were dye loaded with
Carbazole dye. At a
potential of 0.4 V, the
DSSC dye loaded with
Carbazole for 1 hour had
an electron lifetime of 0.1 seconds.
At a potential of 0.4 V, the DSSC
dye loaded with Carbazole for 3
hours had an electron lifetime of 0.4 seconds. At a potential of 0.4 V, the DSSC dye loaded with
Carbazole for 5 hours had an electron lifetime of 0.3 seconds. At a potential of 0.4 V, the DSSC
dye loaded with Carbazole for 24 hours had an electron lifetime of 0.2 seconds.
Figure 22 Charge lifetime as a function of photovoltage decay plot for the
dye sensitized solar cells with the highest short circuit current (Jsc). The dye
sensitized solar cells were dye loaded with Carbazole dye in four different
time increments (1 hour, 3 hours, 5 hours, and 24 hours).
0.01
0.1
1
10
0 0.1 0.2 0.3 0.4 0.5 0.6
CHARGELIFETIME(S)
PHOTOVOLTAGE (V)
1 Hour Cell 3
3 Hour Cell 1
5 Hour Cell 1
24 Hour Cell 1

40. Lee
39
Figure 23 shows the
charge lifetime for the dye
sensitized solar cells with
the highest short circuit
currents (Jsc) that were dye
loaded with JK2 dye. At a
potential of 0.4 V, the
DSSC dye loaded with JK2
for 1 hour had an electron
lifetime of 0.13 seconds. At
a potential of 0.4 V, the
DSSC dye loaded with JK2 for 3
hours had an electron lifetime of
0.07 seconds. At a potential of 0.4 V, the DSSC dye loaded with JK2 for 5 hours h ad an electron
lifetime of 0.28 seconds. At a potential of 0.4 V, the DSSC dye loaded with JK2 for 24 hours had
an electron lifetime of 0.22 seconds.
Figure 23 Charge lifetime as a function of photovoltage decay plot for the
dye sensitized solar cells with the highest short circuit current (Jsc). The
dye sensitized solar cells were dye loaded with JK2 dye in four different
time increments (1 hour, 3 hours, 5 hours, and 24 hours).
0.01
0.1
1
10
0 0.1 0.2 0.3 0.4 0.5 0.6
CHARGELIFETIME(S)
PHOTOVOLTAGE (V)
1 Hour Cell 2
3 Hour Cell 3
5 Hour Cell 1
24 Hour Cell 1

41. Lee
40
Figure 24 shows the
charge lifetime for the dye
sensitized solar cells with the
highest short circuit currents
(Jsc) that were dye loaded with
N719 dye. At a potential of
0.4 V, the DSSC dye loaded
with N719 for 1 hour had an
electron lifetime of 0.08
seconds. At a potential of 0.4
V, the DSSC dye loaded with
N719 for 3 hours had an electron
lifetime of 0.34 seconds. At a
potential of 0.4 V, the DSSC dye loaded with N719 for 5 hours had an electron lifetime of 0.51
seconds. At a potential of 0.4 V, the DSSC dye loaded with N719 for 24 hours had an electron
lifetime of 0.26 seconds.
Figure 24 Charge lifetime as a function of photovoltage decay plot for the
dye sensitized solar cells with the highest short circuit current (Jsc). The dye
sensitized solar cells were dye loaded with N719 dye in four different time
increments (1 hour, 3 hours, 5 hours, and 24 hours).
0.01
0.1
1
10
0 0.1 0.2 0.3 0.4 0.5 0.6
CHARGELIFETIME(S)
PHOTOVOLTAGE (V)
1 Hour Cell 1
3 Hour Cell 2
5 Hour Cell 1
24 Hour Cell 4

42. Lee
41
Figure 25 shows
the charge lifetime for the
dye sensitized solar cells
with the highest short
circuit currents (Jsc) that
were dye loaded with
Ru(dcb)(bpy)2 dye. At a
potential of 0.4 V, the
DSSC dye loaded with
Ru(dcb)(bpy)2 for 1 hour
had an electron lifetime of
0.08 seconds. At a potential of 0.4
V, the DSSC dye loaded with
Ru(dcb)(bpy)2 for 3 hours had an electron lifetime of 0.04 seconds. At a potential of 0.4 V, the
DSSC dye loaded with Ru(dcb)(bpy)2 for 5 hours had an electron lifetime of 0.07 seconds. At a
potential of 0.4 V, the DSSC dye loaded with Ru(dcb)(bpy)2 for 24 hours had an electron lifetime
of 0.02 seconds.
Figure 25 Charge lifetime as a function of photovoltage decay plot for the
dye sensitized solar cells with the highest short circuit current (Jsc). The dye
sensitized solar cells were dye loaded with Ru(dcb)(bpy)2 dye in four
different time increments (1 hour, 3 hours, 5 hours, and 24 hours).
0.01
0.1
1
10
0 0.1 0.2 0.3 0.4 0.5
CHARGELIFETIME(S)
PHOTOVOLTAGE (V)
1 Hour Cell 3
3 Hour Cell 2
5 Hour Cell 1
24 Hour Cell 2

43. Lee
42
Figure 26 shows
the charge lifetime for the
dye sensitized solar cells
with the highest short
circuit currents (Jsc) for
Carbazole, JK2, N719,
and Ru(dcb)(bpy)2. At a
potential of 0.35 V, the
DSSCs dye loaded with
JK2 and Ru(dcb)(bpy)2
had equal electron lifetimes of 0.2
seconds. However, as the trend
continues the electron lifetime of
Ru(dcb)(bpy)2 is slightly longer, but the trends are very similar. At a potential of 0.35 V, N719 has
the highest electron lifetime, 1.50 seconds. Carbazole is closely behind with an electron lifetime
of 0.83 seconds. Overall, the trends of the photovoltage decays of Carbazole and N719 are similar
with N719 having a slightly longer electron lifetime.
Figure 26 Charge lifetime as a function of photovoltage decay plot for the dye
sensitized solar cells with the highest short circuit current (Jsc) for each of the 4
respective dyes (Carbazole, JK2, N719, and Ru(dcb)(bpy)2). The dye sensitized
solar cells were dye loaded in four different time increments (1 hour, 3 hours, 5
hours, and 24 hours).
0.01
0.1
1
10
0 0.1 0.2 0.3 0.4 0.5 0.6
CHARGELIFETIME(S)
PHOTOVOLTAGE (V)
Carbazole 5 Hour Cell 1
JK2 1 Hour Cell 3
N719 5 Hour Cell 1
Ru(dcb)bpy 1 Hour Cell 3

44. Lee
43
Incident Photon-to-Current Conversion Efficiency (IPCE) Data
Dye Wavelength (nm) Incident Photon-to-Current
Conversion Efficiency (IPCE) Ratio
Carbazole 470 nm 0.05
JK2 480 nm 0.06
N719 530 nm 0.47
Ru(dcb)(bpy)2 480 nm 0.29
Cell Type Wavelength
(nm)
Incident Photon-to-Current Conversion
Efficiency (IPCE) %
Carbazole Front Side 470 nm 43.3%
Carbazole Back Side 470 nm 2.3%
JK2 Front Side 480 nm 15.7%
JK2 Back Side 480 nm 1.0%
N719 Front Side 530 nm 51.7%
N719 Back Side 530 nm 24.3%
Ru(dcb)(bpy)2 Front Side 480 nm 8.0%
Ru(dcb)(bpy)2 Back Side 480 nm 2.3%
Table 6 Peak Incident Photon-to-Current Conversion Efficiencies for Carbazole, JK2, N719, and Ru(dcb)(bpy)2
DSSCs fabricated with time dependent dye loading for 5 hours.
Table 7 Ratio of backside to front side Incident Photon-to-Current Conversion Efficiency for Carbazole, JK2,
N719, and Ru(dcb)(bpy)2 DSSCs fabricated with time dependent dye loading for 5 hours.

45. Lee
44
Figure 27
shows the peak
Incident Photon-to-
Current Conversion
Efficiencies (IPCE)
for dye sensitized
solar cells dye loaded
with Carbazole, JK2,
N719, and Ru(bpy).
Backside and front
side illumination
incident photon-to
current conversion efficiencies
(IPCEs) are displayed. For Carbazole DSSCs, the peak incident photon-to-current efficiency
(IPCEmax) is 43.3% at 470 nm for front side illumination. For Carbazole DSSCs, the peak
incident photon-to-current efficiency (IPCEmax) is 2.3% at 470 nm for back side illumination. For
JK2 DSSCs, the peak incident photon-to-current efficiency (IPCEmax) is 15.7% at 480 nm for
front side illumination. For JK DSSCs, the peak incident photon-to-current efficiency (IPCEmax)
is 1.0% at 480 nm for back side illumination. For N719 DSSCs, the peak incident photon-to-
current efficiency (IPCEmax) is 51.7% at 530 nm for front side illumination. For N719 DSSCs,
the peak incident photon-to-current efficiency (IPCEmax) is 24.3% at 530 nm for back side
illumination. For Ru(dcb)bpy DSSCs, the peak incident photon-to-current efficiency (IPCEmax)
Figure 27 Spectra of incident photon-to-current conversion efficiencies
(IPCEs) for dye sensitized solar cells (DSSCs) based on Carbazole, JK2,
N719, Ru(dcb)(bpy)2 dye. The DSSCs were dye loaded for 5 hours.
0
10
20
30
40
50
400 450 500 550 600 650 700 750 800
IPCE(%)
WAVELENGTH (NM)
Carbazole Front Side
Carbazole Back Side
Ru(bpy) Front Side
Ru(bpy) Back Side
N719 Front Side
N719 Back Side
JK2 Front Side
JK2 Back Side

46. Lee
45
is 8.0% at 480 nm for front side illumination. For Ru(dcb)(bpy)2 DSSCs, the peak incident
photon-to-current efficiency (IPCEmax) is 2.3% at 480 nm for back side illumination.
Figure 28
demonstrates the ratio of
incident photon-to-current
conversion efficiency
(IPCE) back side to front
side illumination for each
of the four dyes. The ratio
of back side to front side
IPCE for dye sensitized
solar cells (DSSCs) dye
loaded with Carbazole is 0.05 at
470 nm. The ratio of back side to
front side IPCE for dye sensitized
solar cells (DSSCs) dye loaded with JK2 is 0.06 at 480 nm. The ratio of back side to front side
IPCE for dye sensitized solar cells (DSSCs) dye loaded with N719 is 0.47 at 530 nm. The ratio of
back side to front side IPCE for dye sensitized solar cells (DSSCs) dye loaded with Ru(dcb)(bpy)2
is 0.29 at 480 nm.
Figure 28 Ratio of incident photon-to-current conversion efficiencies
(IPCEs), back side and front side illumination, for dye sensitized solar cells
(DSSCs) based on Carbazole, JK2, N719, Ru(dcb)(bpy)2 dye. The DSSCs
were dye loaded for 5 hours.
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Carbazole JK2 N719 Ru(dcb)(bpy)2
IPCERatio
Dyes

47. Lee
46
Discussion and Analysis
Hypothesis I:
Solar conversion efficiency data indicated that the dyes with higher efficiencies (N719 and
JK2) had the highest efficiencies when dye loaded for 5 hours however, the dyes with lower
efficiencies achieved their highest efficiencies when dye loaded for one hour. The highest
efficiency produced from a dye sensitized solar cell dye loaded with Carbazole dye produced an
efficiency of 2.64%, and was dye loaded for 5 hours. The highest efficiency produced from a dye
sensitized solar cell dye loaded with JK2 produced an efficiency of 0.40%, and was dye loaded for
1 hour. The highest efficiency produced from a dye sensitized solar cell dye loaded with N719
produced an efficiency of 2.32%, and was dye loaded for 5 hours. The highest efficiency produced
from a dye sensitized solar cell dye loaded with Ru(dcb)(bpy)2 produced an efficiency of 0.52%,
and was dye loaded for 1 hour. From the solar conversion efficiency data, we can conclude that as
dye loading time progresses solar conversion efficiency increases. For dye sensitized solar cells
dye loaded with JK2 and Ru(dcb)(bpy)2, although the solar cells with the highest efficiencies were
dye loaded for 1 hour, the other cells dye loaded for longer produced efficiencies merely decimal
points away and so we can conclude that it is merely coincidental that this occurred.
Electron lifetime data was used to confirm that as dye loading time increases solar
conversion efficiency increases. Analyses of photovoltage decay plots indicated that electrons had
longer lifetimes as dye loading times increased. For dye sensitized solar cells dye loaded with
Carbazole, JK2, and N719 the solar cells with the shortest electron lifetime were all dye loaded for
1 hour. For dye sensitized solar cells dye loaded with Ru(dcb)(bpy)2, the solar cell shortest electron
lifetime was dye loaded for 24 hours, however since the decays from the dye sensitized solar cells

48. Lee
47
dye loaded with Ru(dcb)(bpy)2, in general, were not that great we can conclude that this was
coincidental, and due to poor dye sensitized solar cell construction. In addition, the next dye
sensitized solar cell (DSSC) that was dye loaded with Ru(dcb)(bpy)2 with the shortest electron
lifetime was dye loaded for 1 hour. For dye sensitized solar cells dye loaded with Carbazole and
JK2 dye, the longest electron lifetime was found in dye sensitized solar cells dye loaded overnight
followed by the cells dye loaded for 5 hours. For dye sensitized solar cells dye loaded with N719
dye, the longest electron lifetime was found in dye sensitized solar cells dye loaded for 5 hours
followed by the cells dye loaded for 3 hours.
Hypothesis II:
Data gathered using UV-vis spectrometry indicated that Carbazole had the highest
extinction coefficient of 44,817 M-1
cm-1
, followed by JK2 (27,380 M-1
cm-1
), N719 (14,007 M1
cm-
1
), and Ru(dcb)bpy2 (12,142 M-1
cm-1
). In theory, those dyes with the largest extinction coefficient
have the best ability to absorb light. Despite having one of the lowest extinction coefficients, N719
had the largest spectra range from 400 nm to 750 nm. While Carbazole had an absorption spectra
range from 400 nm to 650 nm. JK2 had the shortest absorption spectra from 400 nm to 600 nm.
Ru(dcb)(bpy)2 had an absorption spectra range from 400 nm to 620 nm. As large spectra range
indicates more colors of light will be absorbed and since the cells were exposed to white light,
absorbing more colors in the spectrum lead to a larger efficiency.
Solar conversion efficiency data indicated that the dye sensitized solar cell that produced
the highest efficiency out of all solar cells tested was dye loaded with Carbazole dye for 5 hours.
The solar conversion efficiency produced was 2.64%. The dye sensitized solar cell with the second
highest efficiency was dye loaded with N719. The solar conversion efficiency achieved was

49. Lee
48
2.32%. None of the dye sensitized solar cells dye loaded with JK2 for any of the dye loading times
had a solar conversion efficiency higher than N719 even though, JK2 has an extinction coefficient
that is almost double that of N719. In fact, dye sensitized solar cells dye loaded with JK2 had about
the same solar conversions efficiencies as Ru(dcb)(bpy)2 even though, Ru(dcb)(bpy)2 had the
smallest extinction coefficients out of all the dyes.
Hypothesis III:
Incident Photon-to-Current Efficiency (IPCE) data indicated that Ruthenium dyes have a
better ability at transporting electrons through the TiO2 conduction band than organic dyes. The
highest recorded front side Incident Photon-to-Current Conversion Efficiency (IPCE) out of all the
dyes was 51.7% at 530 nm, and was produced from a dye sensitized solar cell dye loaded with
N719 dye for 5 hours. The second highest front side Incident Photon-to-Current Conversion
Efficiency (IPCE) was 43.3% at 470 nm, and was followed by JK2 with a front side Incident
Photon-to-Current Conversion Efficiency (IPCE) of 15.7% at 480 nm, and Ru(dcb)(bpy)2 with a
front side Incident Photon-to-Current Conversion Efficiency (IPCE) of 8.0% at 480 nm. Although,
Carbazole had a high front side Incident Photon-to-Current Conversion Efficiency (IPCE)
percentage the back side Incident Photon-to-Current Conversion Efficiency (IPCE) percentage
was the second lowest recorded out of all the dyes and so the ratio of back side to front side Incident
Photon-to-Current Conversion Efficiency (IPCE) for dye sensitized solar cells dye loaded with
Carbazole was the lowest of all the 4 dyes. The Incident Photon-to-Current Conversion Efficiency
(IPCE) ratio for a dye sensitized solar cell dye loaded with Carbazole for 5 hours was 0.05. The
dye sensitized solar cell dye loaded with JK2 had the second lowest Incident Photon-to-Current
Conversion Efficiency (IPCE) ratio of 0.06. This indicates that organic dyes are not very good at

50. Lee
49
electron collection through the TiO2 conduction band, and that a majority of the electrons are being
lost to interception in the back side Incident Photon-to-Current Conversion Efficiency (IPCE). On
the other hand, the Ruthenium dyes had the two highest Incident Photon-to-Current Conversion
Efficiency (IPCE) ratios of back side to front side illumination. The Incident Photon-to-Current
Conversion Efficiency (IPCE) ratio for a dye sensitized solar cell dye loaded with N719 for 5 hours
was 0.47. The Incident Photon-to-Current Conversion Efficiency (IPCE) ratio for a dye sensitized
solar cell dye loaded with Ru(dcb)(bpy)2 for 5 hours was 0.29. This evidence suggests that
Ruthenium dyes are better at electron collection from the TiO2 conduction band than organic dyes,
and do not loose many electrons to interception on back side illumination.
Electron lifetime data indicated that when comparing dyes of similar efficiencies the
electron lifetime was longer in Ruthenium dyes. N719 and Carbazole had similar efficiencies for
all times, however, N719 demonstrated a longer electron lifetime. JK2 and Ru(dcb)(bpy)2 had
similar efficiencies and Ru(dcb)(bpy)2 demonstrated a longer electron lifetime. This suggests that
Ruthenium dyes are able to collect more electrons in the TiO2 conduction band and transfer those
to current than organic dyes.

51. Lee
50
Experimental Error
Human error may have occurred during construction of dye sensitized solar cells, however,
large trial size accounted for errors made during solar cell construction, and the experimenter
constructing the dye sensitized solar cells was kept constant throughout the experiment. An
estimated total of one third of the dye sensitized solar cells were shorted throughout this
experiment, and data was not collected for shorted solar cells. Dye sensitized solar cells can short
due to a number of causes such as improper sealing of the cell, improper attachment of
nanoparticles, pinholes caused by electrolyte, improper attachment of fluorine doped tin oxide
(FTO), excess of epoxy paste, etc. All shorted cells were reconstructed and retested to ensure
accurate results. During the time when data was being collected at Northwestern University, there
were problems with the Atomic Layer Deposition (ALD) which caused incomplete deposition of
TiO2 blocking layer on fluorine doped tin oxide (FTO) glass for the dye sensitized solar cells
(DSSCs). This error in the Atomic Layer Deposition (ALD) caused pinholes in some dye sensitized
solar cells. Also, the lamp used to test the solar cells was getting old and suffering from some
power fluctuations which caused some of the J-V curves to become a bit noisy. Towards the end
of experimentation, the dyes were beginning to become a bit old and that led to the cause of lower
efficiencies in retesting, but the general results still affirm the conclusion. All variables were held
constant throughout the course of experimentation and proper laboratory skills were used to
conduct research. Data contamination was avoided by wearing gloves and by washing all
equipment used in between procedural steps.

52. Lee
51
Conclusion
The overall purpose of this experiment was to explore the mechanisms at work in dye
sensitized solar cells in order to construct the most efficient solar cell. The first hypothesis
predicted that there would be a direct relationship between dye loading times of nanoparticles
and solar conversion efficiency. Meanwhile, the second hypothesis predicted that an extinction
coefficient of a dye would not be the sole factor affecting solar conversion efficiency. The third
hypothesis indicated that the difference in dye structure between Ruthenium and organic dyes
would dictate the abilities of electrons through the beneficial and parasitic kinetic processes in a
dye sensitized solar cell.
Over 60 dye sensitized solar cells were constructed throughout the course of this
experiment. The dye sensitized solar cells were dye loaded with 4 dyes (Carbazole, JK2, N719,
and Ru(dcb)(bpy)2) for 4 different time periods (1 hour, 3 hours, 5 hours, and overnight). UV-vis
spectrometry was used to determine the extinction coefficients of the dyes, which determines
which dyes have the best ability to absorb light. A potentiostat was used to obtain J-V curves,
electron lifetimes, and Incident Photon-to-Current Conversion Efficiencies (IPCEs). J-V curves
were used to generate solar conversion efficiency. Electron lifetime plots were used to determine
how many electrons were collected across the TiO2 conduction band and converted to current.
Incident Photon-to-Current Conversion Efficiency (IPCE) data was used to determine how many
photons of light were being collected per electron.
In summary, hypothesis II and III were proven true, and hypothesis I must be revised.
As dye loading time increased so did solar conversion efficiency for cells dye loaded with
Carbazole and N719, however, the dye sensitized solar cells dye loaded with Carbazole and

53. Lee
52
N719 for 5 hours often had greater solar conversion efficiencies than those dye loaded overnight,
and so for future experimentation one should look into dye loading times between 5 hours, but
less than 24 hours. Ru(dcb)(bpy)2 and JK2 demonstrated the highest efficiencies dye loaded after
1 hour, however, the electron lifetimes were longest as dye loading time increased. This indicates
that not much of the electrons are being transferred to current when being dye loaded for short
amounts of time. Extinction coefficients were found not to be the sole factor affecting solar
conversion efficiency as N719 outperformed JK2, although JK2 had a far higher extinction
coefficient. The data gathered from this experiment suggested that Ruthenium dyes are far better
at electron collection and loose less electrons to interception than organic dyes. The outcomes of
this investigation can look into improving the ability of organic dyes to handle the parasitic and
beneficial kinematic processes in dye sensitized solar cells. The implications of this experiment
can give insight in the processes that need to be improved in order to move dye sensitized solar
cell technology forward to compete with other alternative energy sources and fossil fuels.

54. Lee
53
Appendix
Solar Conversion Efficiency for All DSSCs
Carbazole Dye Sensitized Solar Cells
Cell Type Jsc (mA/cm2) Voc (V) Fill
Factor
Efficiency (%)
1 Hour Cell 1 0.847579 0.575039 0.598 0.291337
1 Hour Cell 1 Dark Current -0.00029663 -0.02236719 0.38062351 2.53E-06
1 Hour Cell 2 0.822094 0.541278 0.637 2.84E-01
1 Hour Cell 2 Dark Current -0.0005832 -0.00252 -0.51121 -7.50E-07
1 Hour Cell 3 2.6072136 0.6024743 0.73346187 1.15210663
1 Hour Cell 3 Dark Current -0.00040826 -0.0889124 0.32332256 1.17E-05
3 Hour Cell 1 4.59148 0.609715 0.724502 2.028238
3 Hour Cell 1 Dark Current -0.00034 -0.08366 0.411554 1.18E-05
3 Hour Cell 2 3.618585 0.624582 0.577 1.30371
3 Hour Cell 2 Dark Current -0.00026 -0.07241 0.376347 7.21E-06
5 Hour Cell 1 5.832836 0.614849 0.737735 2.645748
5 Hour Cell 1 Dark Current -0.00037 -0.04762 0.946957 1.67E-05
5 Hour Cell 2 3.253983 0.590068 0.589 1.130267
5 Hour Cell 2 Dark Current -0.00021 -0.02224 0.395717 1.83E-06
5 Hour Cell 3 0.858498 0.556953 0.722 0.345377
5 Hour Cell 3 Dark Current -0.00034941 -0.08696 0.38223171 1.16E-05
5 Hour Cell 4 1.51507 0.575635 0.745 0.649552
5 Hour Cell 4 Dark Current -0.02161435 -0.00066521 0.24436881 3.51E-06
5 Hour Cell 5 2.480678 0.586249 0.78 1.133912
5 Hour Cell 5 Dark Current -0.00041374 -0.08675139 0.24976016 8.96E-06
5 Hour Cell 6 2.156789 0.583468 0.346956 0.436616
5 Hour Cell 6 Dark Current -0.00044 -0.0868 0.339081 1.30E-05
24 Hour Cell 1 3.403884 0.593627 0.696532 1.407438
24 Hour Cell 1 Dark Current -0.00038 -0.0822 0.423282 1.32E-05
24 Hour Cell 2 3.377783 0.61066 0.682 1.40695
24 Hour Cell 2 Dark Current -0.04911197 -0.0004102 0.14782894 2.98E-06
24 Hour Cell 3 3.154673 0.598284 0.724 1.365889
24 Hour Cell 3 Dark Current -0.08682 -0.00031 0.5605 1.49E-05
24 Hour Cell 4 3.055013 0.598128 0.661 1.206954
24 Hour Cell 4 Dark Current -0.00051 -0.08662 0.322143 1.42E-05
JK2 Dye Sensitized Solar Cells
1 Hour Cell 1 0.158874 0.530385 0.648 0.054609
1 Hour Cell 1 Dark Current -0.00039203 -0.04492563 0.212 3.73E-06
1 Hour Cell 2 0.9503404 0.5708585 0.72980967 0.395928969
1 Hour Cell 2 Dark Current -0.00077229 -0.08762898 0.33911656 2.29E-05

55. Lee
54
Solar Conversion Efficiency for All DSSCs
JK2 Dye Sensitized Solar Cells
Cell Type Jsc
(mA/cm2)
Voc (V) Fill
Factor
Efficiency
(%)
1 Hour Cell 3 0.572 0.546 0.638 0.199
1 Hour Cell 3 Dark Current -0.0004 -0.068 1.010 2.64E-05
3 Hour Cell 1 0.104 0.505 0.416 0.022
3 Hour Cell 1 Dark Current -0.0007 -0.050 0.142 5.08E-06
3 Hour Cell 2 0.201 0.499 0.598 0.060
3 Hour Cell 2 Dark Current -0.058 -0.0003 0.250 4.69E-06
3 Hour Cell 3 0.764 0.547 0.764 0.320
3 Hour Cell 3 Dark Current -0.0003 -0.083 0.483 1.26E-05
5 Hour Cell 1 0.542 0.596 0.590 0.190
5 Hour Cell 1 Dark Current -0.0004 -0.088 0.510 1.64E-05
5 Hour Cell 2 0.398 0.567 0.590 0.133
5 Hour Cell 2 Dark Current -0.0002 -0.088 0.803 1.65E-05
Overnight Hour Cell 1 0.586 0.561 0.751 0.247
Overnight Hour Cell 1 Dark Current -0.0004 -0.075 0.425 1.20E-05
Overnight Hour Cell 2 0.452 0.440 0.309 0.062
Overnight Cell 2 Dark Current -0.002 -0.003 -0.67 -2.60E-06
N719 Dye Sensitized Solar Cells
1 Hour Cell 1 4.315 0.65 0.554 1.555
1 Hour Cell 1 Dark Current -0.0061 -0.00250 -0.638 -9.79E-06
1 Hour Cell 2 3.833 0.683 0.653 1.710
1 Hour Cell 2 Dark Current -0.00038 -0.057 0.603 1.32E-05
3 Hour Cell 1 Lighter 1.867 0.665 0.611 0.758
3 Hour Cell 1 Dark Current -0.00035 -0.085 0.430 1.28E-05
3 Hour Cell 2 Darker 4.409 0.667 0.461 1.357
3 Hour Cell 2 Dark Current -0.00034 -0.079 0.394 1.06E-05
5 Hour Cell 1 4.574 0.664 0.764 2.322
5 Hour Cell 1 Dark Current -0.00038 -0.079 0.459 1.36E-05
Overnight Hour Cell 1 4.561 0.6248 0.516 1.470
Overnight Hour Cell 1 Dark Current -0.0082 -0.0024 -0.375 -7.41E-06
Overnight Hour Cell 2 2.671 0.675 0.804 1.449
Overnight Hour Cell 2 Dark Current -0.0003 -0.057 0.430 7.72E-06
Overnight Hour Cell 3 2.641 0.646 0.868 1.48
Overnight Hour Cell 3 Dark Current -0.00082 -0.083 0.261 1.77E-05
Overnight Hour Cell 4 3.792 0.681 0.796 2.056
Overnight Hour Cell 4 Dark Current -0.00026 -0.083 0.191 4.06E-06
Ru(dcb)(bpy)2 Dye Sensitized Solar Cells
1 Hour Cell 1 0.464 0.190 0.312 0.0275

56. Lee
55
Solar Conversion Efficiency for All DSSCs
Ru(dcb)bpy Dye Sensitized Solar Cells
Cell Type Jsc
(mA/cm2)
Voc (V) Fill
Factor
Efficiency
(%)
1 Hour Cell 1 Dark Current 0.465585 0.19041 0.295322 0.026181
1 Hour Cell 2 0.484747 0.469352 0.368 0.083634
1 Hour Cell 2 Dark Current -0.00127331 -0.00230959 -0.6015174 -1.77E-06
1 Hour Cell 3 1.1732648 0.5725148 0.78113173 0.524695139
1 Hour Cell 3 Dark Current -0.00055583 -0.06829166 0.30434429 1.16E-05
3 Hour Cell 1 0.43258 0.511178 0.752 0.166332
3 Hour Cell 1 Dark Current -0.00036488 -0.08466394 0.6611122 2.04E-05
3 Hour Cell 2 0.474506 0.510114 0.76 0.184047
3 Hour Cell 2 Dark Current -0.0003171 -0.08264601 0.44900847 1.18E-05
5 Hour Cell 1 1.165124 0.555846 0.698 0.452185
5 Hour Cell 1 Dark Current -0.00044564 -0.04226046 0.34602322 6.52E-06
5 Hour Cell 2 0.920766 0.076007 4.285798 0.299939
5 Hour Cell 2 Dark Current -0.00041699 -0.0475621 0.19639302 3.90E-06
Overnight Hour Cell 1 0.566292 0.520412 0.56 0.165001
Overnight Hour Cell 1 Dark
Current
-0.00037 -0.04824 0.131059 2.37E-06
Overnight Hour Cell 2 0.566988 0.510089 0.751 0.21726
Overnight Hour Cell 2 Dark Current -0.00057 -0.02964 0.151541 2.56E-06

57. Lee
56
Literature Cited
Cheng, M., Yang, X., Li, J., Zhang, F., & Sun, L. (2013). Co-sensitization of Organic Dyes
for Efficient Dye-Sensitized Solar Cells. ChemSusChem, 6(1), 70-77.
Dye Sensitized Solar Cells | DSSC | GCell. (n.d.). Retrieved December 14, 2014, from
http://gcell.com/dye-sensitized-solar-cells
Dye-sensitized solar cells rival conventional cell efficiency. (n.d.). Retrieved March 7, 2015,
from http://phys.org/news/2013-07-dye-sensitized-solar-cells-rival-conventional.htm
Electrode of Dye-Sensitized Solar Cells Analysed by Voltage Decay and Charge
Extraction. International Scholarly Research Notices, 2011.
El-Shafei, A., Hussain, M., Atiq, A., Islam, A., & Han, L. (2012). A novel carbazole-based dye
outperformed the benchmark dye N719 for high efficiency dye-sensitized solar cells
(DSSCs). Journal of Materials Chemistry, 22(45), 24048-24056.
Hagfeldt, A., Boschloo, G., Sun, L., Kloo, L., & Pettersson, H. (2010). Dye-Sensitized
Solar Cells. Chemical Reviews, 6595-6663.
Ito, S., Humphry-Baker, R., Liska, P., Comte, P., Péchy, P., Nazeeruddin, M. K., & Grätzel,
M. (2011). Electron-Density and Electron-Lifetime Profile in Nanocrystalline-T i O 𝟐
Kim, J. H., Kang, M. S., Kim, Y. J., Won, J., Park, N. G., & Kang, Y. S. (2004). Dye-sensitized
nanocrystalline solar cells based on composite polymer electrolytes containing fumed
silica nanoparticles. Chemical communications, (14), 1662-1663.
Luc, Brian. (2010). "Dye-Sensitized Solar Cells." Dye-Sensitized Solar Cells. N.p. Web. 18
Dec. 2014.

58. Lee
57
Miyashita, M., Sunahara, K., Nishikawa, T., Uemura, Y., Koumura, N., Hara, K., ... & Mori, S.
(2008). Interfacial electron-transfer kinetics in metal-free organic dye-sensitized solar
cells: combined effects of molecular structure of dyes and electrolytes. Journal of the
American Chemical Society, 130(52), 17874-17881.
Nelson, J. (2003). The physics of solar cells. London: Imperial College Press.
Sharifi, N., Tajabadi, F., & Taghavinia, N. (2014). Recent Developments in Dye‐Sensitized Solar
Cells. ChemPhysChem.
Yum, J., Chen, P., Grätzel, M., & Nazeeruddin, M. K. (2008). Recent Developments in
Solid-State Dye-Sensitized Solar Cells. ChemSusChem,1(8-9), 699-707.