This document discusses organic solar cells, which convert light to electricity using conjugated polymers and molecules rather than traditional silicon materials. It provides background on the need for alternative energy sources due to growing energy demand and limited fossil fuels. Organic solar cells absorb light, transfer charges, transport the separated charges, and collect them. Researchers have achieved a new record efficiency of 15.6% for a graphene-based solar cell that uses titanium oxide, graphene, and perovskite, manufactured via low-temperature solution deposition. While organic solar cells offer advantages like lower costs and flexibility, their efficiency remains below silicon cells and they suffer from degradation. Further improving charge carrier transport and interface engineering is needed to enhance performance.

1. INTRODUCTION
 SOLAR CELL
Solar cell or photovoltaic cell, is an electrical device that converts the energy of
light directly into electricity by the photovoltaic cells.
 ORGANIC SOLAR CELL
The approach is based on solar cell made by entirely new materials, conjugated
polymers and molecules.

2. Need…
 Global energy crisis.
• Energy demand will double in next 50 years.
• Fossil fuels stock is running out
The amount of solar energy intercepted by the earth
in 1 hour is more than the annual world energy
consumption

4. PROCESSES IN AN ORGANIC SOLAR CELL
• Absorption of light
• Charge transfer and separation of the opposite
charges
• Charge transportation
• Charge collection

5. Latest work…
 Researchers at Spain's Universitat Jaume I in Castelló and Oxford
University are claiming a new record efficiency of 15.6 percent
for a graphene-based solar cell.
 It uses a combination of titanium oxide and graphene as a charge
collector and perovskite as a sunlight absorber.
 It is manufactured at low temperatures using a solution based
deposition technique
 Advantages :-
 lower potential production costs
 technology can also be used on flexible plastics.

6. EXPERIMENTAL OUTLOOK
 Measurements of Current−voltage, capacitance−voltage,
and external quantum efficiency are taken.
 Doping with bis-(trifluoromethanesulfonyl)amide in
graphene leads to a shift in chemical potential which
increases .
 the graphene carrier density (decreasing the cell
series resistance)
 the cell’s built-in potential (increasing the open
circuit voltage)
both of which improve the solar cell fill factor.
a) Without Doping b) With Doping

7. Advantages and Disadvantages:-
 Advantages
Environmentally Safe
Flexible
Lightweight
Inexpensive
 Disadvantages
Low efficiency (only 8% efficiency compared to the 25% of silicon cells)
Short lifetime

8. Technological Importance :-
Bring some polymer paint and coat the windows and walls to make
your own solar cell
Transportation
Military use

9. FUTURE CHALLENGES
 The present efficiency of polymer solar cells lies near 10%, well below silicon cells.
 Polymer solar cells also suffer from environmental degradation, lacking effective protective
coatings.
 Further improvements in performance are needed
 to promote charge carrier diffusion
 transport must be enhanced through control of order and morphology
 interface engineering must be applied to the problem of charge transfer across interfaces.

10. REFERENCES
 Introduction to polymer solar cells (3Y280) by René Janssen
Departments of Chemical Engineering & Chemistry and Applied Physics
Eindhoven University of Technology, The Netherlands
 Bonaccorso, F.; Colombo, L.; Yu, G.; Stoller, M.; Tozzini, V.; Ferrari, A. C.; Ruoff, R. S.;
Pellegrini, V. Graphene, related two dimensional crystals, and hybrid systems for energy
conversion and storage
 M. Xiaochang, T. Sefaattin, P. Maureen, B. Kara, R. Andrew, A. Bill, H. Arthur, High
efficiency solar cells by chemical doping, Nano Letters.
 www.Wikipedia.org
 www.google.com

11. Thanks !