Dye-sensitized solar cells (DSSCs) are a low-cost alternative to conventional solar cells, utilizing natural dyes for light absorption and showing potential for applications in building-integrated photovoltaics. They consist of components like a semiconducting electrode, dye sensitizer, redox electrolyte, and counter electrode, offering advantages such as high performance-price ratio and operation in low light conditions. However, they face challenges like lower efficiencies and issues with dye stability and liquid electrolyte leakage.

1. Submitted by:
Preeti choudhary (17/MAP/016)
M.Sc.(Applied Physics)

2. content
• Introduction to DSSC
• Principle and working of DSSC
• Component involved in DSSC
• How Does DSSC work?
• Advantage and Disadvantage
• Application

3. •Renewable energy sources such as solar energy are
considered as a feasible alternative because
“More energy from sunlight strikes Earth in 1 hour than all
of the energy consumed by humans in an entire
year.”(Lewis, 2007).
• The use of natural dye extracts provides natural, non toxic
and low cost dye sources with high absorbance level of
UV, visible and near IR.
• Examples of such dye sources are Bahraini Henna
(Lawsonia inermis L.) and Bahraini raspberries (Rubus spp.).
Introduction

4. Disadvantages of Conventional Solar
cells
o Costly equipment
o Environmental Impact of PV Cell Production
o Initial cost is very high
o Requires expert hand and equipment in
manufacture

5. Semiconductor Solar
Cells
DSSC
Transparency Opaque Transparent
Environment(Material&
Process)
Normal Great
Power Generation cost High Low
Power Generation
efficiency
High Normal
Color Limited Various

6. What is a DSSC?
A dye sensitized solar cell is a new kind of
relatively low cost solar cell with great
potential as its materials are considerably
cheaper and it is simple to make.

7. Past
• Michael Grätzel and Brian O’Regan invented “Dye-
sensitized solar cells”, also called “Grätzel cells”, in
2005.
• The first cells were only capable of using light at the
Ultraviolet and Blue end of the spectrum.
• By the turn of the century, advances in technology
were able to broaden the frequencies in which these
cells were able to respond.
• The most efficient of the dyes were simply known as
“Black dyes” due to their very dark colors.

8. Components
The DSSC device consists of 4 components:
Semiconducting electrode
• n-type TiO and p-type NiO
Dye-sensitizer
• Light harvesting and electronic transition
Redox mediator
• I- / I3
- or CoII / CoIII complexes
Counter electrode
• Carbon or Pt

9. 1. Transparent substrate for both the conducting
electrode and counter electrode
• Clear glass substrates are commonly used as substrate because of
their relative low cost, availability and high optical transparency in
the visible and near infrared regions of the electromagnetic
spectrum.
• TCFs for photovoltaic applications have been fabricated from both
inorganic and organic materials.
• Inorganic films typically are made up of a layer of transparent
conducting oxide (TCO),generally in the form of indium tin oxide
(ITO), fluorine doped tin oxide (FTO), and doped zinc oxide.

10. 2.Nanostructured photoelectrode
• In the old generations of photo electro chemical solar
cells (PSC) photo electrodes were made from bulky
semiconductor materials such as Si, GaAs or CdS.
• However, these kinds of photo electrodes when
exposed to light they undergo photo corrosion that
results in poor stability of the photoelctrochemical cell.
• The use of sensitized wide bandgap semiconductors
such as TiO₂ , or ZnO resulted in high chemical stability
of the cell due to their resistance to photo corrosion.

11. • The problem with bulky single or poly-crystalline
wide band gap is the low light to current
conversion efficiency mainly due to inadequate
adsorption of sensitizer because of limited surface
area of the electrode.
• One approach to enhance light-harvesting
efficiency (LHE) and hence the light to current
conversion efficiency is to increase surface area (the
roughness factor) of the sensitized photo electrode.

12. 3.Photosensitizer
• Dye molecules of proper molecular structure are used to
sensitized wide bandgap nanostructured photoelectrode.
• Upon absorption of photon, a dye molecule adsorbed to
the surface of say nanostructured TiO₂ gets oxidized and
the excited electron is injected into the nanostructured
TiO₂.
• Sensitizations of natural dye extracts such as shiso leaf
pigments, Black rice, Fruit of calafate, Rosella ,Natural
anthocyanins ,Henna and wormwood have been
investigated and photovoltaic action of the tested cells
reveals some opportunities.

13. Redox electrolyte
• Electrolyte containing I⁻/3I⁻
oxidized dye molecules
redox ions is used in DSSC to regenerate the
• This will complete the electric circuit by mediating electrons between the
nanostructured electrode and counter electrode.
• Cell performance is greatly affected by ion conductivity in the electrolyte
which is directly affected by the viscosity of the solvent.
• NaI, LiI and R₄NI (tetraalkylammonium iodide) are well known examples
of mixture of iodide usually dissolved in nonprotonic solvents such as
acetonitrile, propylene carbonate and propionitrile to make electrolyte.
• The redoxing electrolyte needs to be chosen such that the reduction of
I ions by injection of electrons is fast and efficient3
Dye-Sensitized Solar Cells: A Successful Combination of Materials Claudia Longo and Marco-A. De Paoli* Instituto de Química,
Universidade Estadual de Campinas, CP 6154, 13084-971 Campinas - SP, Brazil

14. Mechanism

15. Dye Sensitized Solar Cells - Working Principles,
Challenges and Opportunities Khalil Ebrahim Jasim Department of Physics, University of Bahrain Kingdom of Bahrain
Schematic of the structure of the dye sensitized solar cell.

16. Illustration of operation principle of dye sensitized solar cell

17. TiO2 Dye Electrolyte Cathode
Wide band-gap
semiconductor

18. -0.5
0
0.5
TiO2
1.0
S*
S°/S+
Dye Electrolyte
OxRed
Cathode
Electron energy
(eV vs. NHE)
-1.0
e-
Wide band-gap
semiconductor

19. 1. Light absorption-0.5
0
0.5
TiO2
1.0
S*
S°/S+
hν
Dye Electrolyte
OxRed
Cathode
1
Electron energy
(eV vs. NHE)
-1.0
e-
Wide band-gap
semiconductor
h+

20. 1.
2.
Light absorption
Injection to
semiconductor
3. Percolation
-0.5
0
0.5
TiO2
1.0
S*
S°/S+
hν
Dye Electrolyte
OxRed
Cathode
1
2
3
Electron energy
(eV vs. NHE)
-1.0
e-
Wide band-gap
semiconductor
h+

21. 1.
2.
Light absorption
Injection to
semiconductor
Percolation3.
4. Regeneration of
oxidized dye
-0.5
0
0.5
TiO2
1.0
S*
S°/S+
hν
Dye Electrolyte
OxRed
Cathode
1
2
3
4
Electron energy
(eV vs. NHE)
-1.0
Wide band-gap
semiconductor
e-
h+

22. 1.
2.
Light absorption
Injection to
semiconductor
Percolation3.
4. Regeneration of
oxidized dye
5. Regeneration of
oxidized species
-0.5
0
0.5
TiO2
1.0
S*
S°/S+
hν
Dye Electrolyte
OxRed
Cathode
LOAD
e-
External circuit
1
2
3
4
Electron energy
(eV vs. NHE)
-1.0
Wide band-gap
semiconductor
h+
5
h+
e-

23. Maximum Voltage in DSSCs
-0.5
0
0.5
TiO2
1.0
S*
S°/S+
Dye Electrolyte
OxRed
Maximum
Voltage
Cathode
LOAD
e-
External circuit
Electron energy
(eV vs. NHE)
-1.0
e-
Wide band-gap
semiconductor
The voltage is
determined
mainly by the
titania and
redox couple
in the
electrolyte.
h+

24. Natural Dye Performances
Dye-Sensitized Solar Cells: A Successful Combination of Materials : Claudia Longo and Marco-A. De Paoli* Instituto de Química, Universidade Estadual
de Campinas, CP 6154, 13084-971 Campinas - SP, Brazil
Measured absorbance of some extracted natural dyes in methanol as solvent.

25. The DSC vs. Conventional Silicon PV
TiO2
Dye
Electrolyte
Cathode
+
n-type
Silicon
p-type
Silicon
+
+
+
+
• Charge carriers (excited
electrons) are produced
throughout the semiconductor
• Semiconductor considerations:
• Precise doping
• high purity
• high crystalinity
• Light absorption and charge
transport are decoupled
• Relaxed constraints on individual
components (each can be
separately tuned)
• Only monolayer of dye on TiO2

26. Applications Of DSSC
• Because of the physical nature of the dye sensitized solar cells, inexpensive,
environment friendly materials, processing, and realization of various colors,
power window and shingles are prospective applications in building integrated
photovoltaics
• The availability of lightweight flexible dye sensitized cells or modules are
attractive for applications in room or outdoor light powered calculators,
gadgets, and mobiles.
• Flexible dye sensitized solar modules opens opportunities for integrating them
with many portable devices, baggage, gears, or outfits.
• In power generation, dye sensitized modules with efficiency of 10% are
attractive choice to replace the common crystalline Si-based modules.

27. Applications of DSSC
(a) 200 m2 of DSSC panels installed in Newcastle (Australia)– the first
commercial DSSC module

28. (c) flexible DSSC-based solar module developed by Dyesol (http://www.dyesol.com)
(d) jacket commercialized by G24i (http://www.g24i.com).
D

29. Solar Cell Efficiencies
Silicon Solar Cell Efficiencies:
Theoretical Maximum: 26%
Best in Lab: 25% (Green, UNSW)
Modules: 15-22%
Thin Film Solar Cell Efficiencies:
Theoretical Maximum: >22%
Best in Lab: 20% (Noufi, NREL)
Modules: 9-12%
Dye-Sensitized Solar Cell Efficiencies:
Theoretical Maximum: 14-20%
Best in Lab: 12% (Grätzel, EPFL)
Modules: 6-9%

30. 3
0

31. Advantage
• Less Expensive
• Work in low light conditions
• High performance-price ratio
• A variety of colours

32. Disadvantage
• Lower efficiencies
• Breakdown of the Dye
• Liquid Electrolyte may leak

33. Reference
• Gratzel, M. (2005). Solar Energy Conversion by Dye-Sensitized Photovoltaic Cells. Inorg.
Chem., Vol. 44, pp. 6841-6851.
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Lewis, N. S. (2007). Toward Cost-Effective Solar Energy Use. Science, Vol 315, pp. 798-801.
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Nakade, S.; Kubo, W.; Saito, Y.; Kanzaki, T.; Kitamura, T.; Wada, Y.; Yanagida, S. J. Phys.
Chem. B 2003, 107.
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Plass, R.; Pelet, S.; Kruger, J.; Gratzel, M.; Bach, U. J. Phys. Chem. B 2002, 106, 7578.
Nozik, A. J. Quatum dot solar cells. Next Gener. Photovoltaics 2004, 196.
Liska er al. 2006, 88, 203103. Marcus, R. A. 1992, Nobel Lecture.
Bernards, D. A.; Samuel, F. T.; Hector, D. A.; George, G. M. Science, 2006, 313, 1416.
Amao, Y. & Komori, T. (2004).
Bio-photovoltaic conversion device using chlorine-e6 derived from chlorophyll from Spirulina
adsorbed on a nanocrystalline TiO2 film electrode. Biosensors Bioelectronics, Vol. 19, Issue 8,
pp. 843-847.
• Harding, H.E.; Hoke, E.T.; Armistrong, P.B.; Yum, J.; Comte, P.; Torres, T.; Frechet, J.M.J.;
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sensitized solar cells with energy relay dyes. Nature Photonics, Vol. 3, pp. 406-411.
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