Dye-sensitized solar cells (DSSCs) provide a lower-cost alternative to traditional silicon-based solar cells. While DSSCs have lower energy conversion efficiencies than silicon cells, their production process is cheaper and they do not require fragile crystalline structures. DSSCs use dye molecules to absorb sunlight and transfer electrons into a semiconducting layer. This separation of charges generates a voltage and current. In contrast to expensive, rigid silicon cells, DSSCs are inexpensive to manufacture, lightweight, flexible, and have a short energy payback time compared to their cost. Further development could allow DSSCs to achieve grid parity with fossil fuel power generation.

1. Clean Solar Energy DSSC
Technology
PRUTHIRAJ SWAIN
12PS21F

2. Outline
 Introduction(Present Scenario in India)
 Background on Solar Light
 Types of Solar cell
 How a Silicon-Based Solar Cell Works
 How a Dye-Sensitized Cell Works
 Comparison
 Summary

3. Introduction :
 Energy-starved India is becoming a vibrant market for renewable energy.
This bodes well for a country that has often seen its industrial and
economic growth inhibited by a truncated supply of conventional power.
 Currently faces energy shortage of 8 % & a peak demand shortage of
11.6 %.
 In order to sustain a growth rate of 8 %, it is estimated that the power
generation capacity in India would have to increase to 306 GW in the
next 10 years which is 1.7 times current levels.
 Grid-connected renewable power accounts for as much as 20.2 GW – or
11% – of India's 182.3 GW of installed power capacity.
◦ The majority share (55% or 99.8 GW ) – by coal-based thermal power.
◦ Gas-fired thermal power, (10% or 17.7 GW),
◦ Hydropower (21% or 38.7 GW) and nuclear 2.6% with 4780 MW.
◦ India just had 2.12 megawatts of grid-connected solar generation
capacity

4.  Under the 11th Five Year Plan (ended March 2012), Only 52 GW of the
78.6 GW originally envisaged has been added,.
 The 10th Plan (2002-07) only saw a meagre 21.2 GW capacity added,
against a target of 41.1 GW.
 The 12th Plan (2012-17) now aims for a capacity addition of 103.3 GW
which includes commensurate transmission and distribution capacities.
 Clean energy investments in India reached a record US$10.3bn in 2011, up
52% from the US$6.8bn invested in 2010 .This was the highest growth
figure of any significant economy in the world, with the country accounting
for 4% of global investments in clean energy. The large growth was driven
by a 7-fold increase in funding for grid-connected solar projects.
 Solar photovoltaic (PV) power plants totalling over 180 MW were set up in
the country and off-grid installations of over 50 MW were completed as
well.

5. What is Solar Energy?
 Energy produced by the Sun
 Conversion of Sunlight into usable energy such as
electricity and heat.
◦ Clean(No green house gases),
◦ renewable source of energy,
◦ Decentralization of power
Photovoltaic (solar) panel
◦ Saving eco-systems and livelihoods.
 Harnessed by solar collection
methods such as solar cells & Concentrators
 Conversion of Sunlight into usable energy such as
electricity and heat.
Set of solar panels

6. Energy from the Sun is Abundant
 Solar power systems installed in the areas defined by the
darkdisks could meet the world's current Total energy
demand

7. Solar Panel Use Today
Solar panels being tested on
WalMart store
Solar panels on Microsoft
building

8. Photovoltaic Solar Cells
 Generate electricity directly
from sunlight
 2 Main types:
– Single-crystal silicon Silicon Based Solar Cell
(traditional)
 Widespread
 Expensive to manufacture
– Dye-sensitized (“nano”)
 Newer, less proven
 Inexpensive to manufacture
 Flexible
Dye Sensitized Solar Cell

9. PV Technology
Classification
1st Generation 2nd Generation
Silicon Crystalline Technology Thin Film Technology
Mono Crystalline PV Cells Amorphous Silicon PV Cells
Multi Crystalline PV Cells Poly Crystalline PV Cells
( Non-Silicon based)-CIS,CdTe

10. Solar Cells are Converters of
Energy
 Solar cells are devices that take light energy as
input and convert it into electrical energy

11. A Little Background on Light
Different colours of light have different wavelengths and different
energies

12. Absorption of Light by Atoms
 Absorption occurs only when the energy of the
light equals the energy of transition of an
electron
Single
electron
transition in
an isolated
atom

13. Absorption of Light by Ionic
Compounds
 Electrons can jump between “bands”
 Incident light with energy >= than the “band
gap” energy can be used to excite the
electrons

14. So What Does this Mean for Solar
Cells ?
 In dye-sensitized solar cells
– Talk about highest occupied
molecular orbital (HOMO) and
lowest unoccupied molecular
orbital(LUMO)
 In single-crystal silicon
solar cells
– Talk about “conduction band”
(excited states) and “valence
band”(ground states)

15. How a Silicon-Based Solar Cell
Works
 Light with energy greater than the band gap energy of Si
is absorbed
 Energy is given to an electron in the crystal lattice.
 The energy excites the electron; it is free to move.
 A positive “hole" is left in the electron’s place.
 This separation
of electrons and
holes creates a
voltage and a
current.

16. Silicon-Based Solar Cell
Attributes
 Expensive
– Made in high vacuum at high heat
– High manufacturing costs
 Need TLC
– Fragile, rigid, thick
 Long return on investment
– Takes 4 years to produce energy savings
equivalent to cost of production

17. How a Dye-Sensitized Cell
Works
 Light with high enough energy excites electrons in dye
molecules
 Excited electrons infused into semiconducting TiO2,
transported out of cell
 Positive “holes” left in dye molecules
 Separation of excited electrons and “holes” creates a
voltage and hence current.

19. Dye-Sensitized Solar Cells
 Relatively inexpensive
– Made in non-vacuum setting mainly at room temperature
– Relatively simple manufacturing process
 Need little TLC
– Thin, lightweight, flexible
 Short return on investment
– Takes approx 3 months to produce energy savings
equivalent to cost of production

20. Dye-Sensitized and Silicon-based
Solar Cells Compared
 Dye-Sensitized  Traditional
 Relatively  Expensive
inexpensive
– Need little TLC – Need TLC
– Short return on – Long return on
investment investment

21. Summary
 The DSSC has a number of attractive
features.
 Although its conversion efficiency is less than
the best thin-film cells, in theory
its price/performance ratio should be good
enough to allow them to compete with fossil
fuel electrical generation by achieving grid
parity.
 North-western University researchers
announced a solution to a primary problem of
DSSCs, short useful life of the device.. The
current efficiency is about half that of silicon
cells, but the cells are lightweight and
potentially of much lower cost to produce.

22. Further Reading
Konarka Technologies (Graetzel cells) http://www.konarkatech.com/
PV Power Resource Site http://www.pvpower.com/
US DOE Photovoltaics http://www.eere.energy.gov/pv/
Key Center for Photovoltaic Engineering
http://www.pv.unsw.edu.au/
National Center for Photovoltaics http://www.nrel.gov/ncpv/

23.  Thank You!!!
(for patient hearing)