Renewable energy from thin-film organic solar cells
Master of Science Somnath Dey's doctoral thesis focuses on synthesis of novel photoactive molecules and application of those in thin-film based organic solar cells (OSCs).The worldwide demand for energy has grown enormously over the last century as a consequence of the increasing rate of industrialization throughout the world. With the improvements of living standards across the planet, the need for energy is likely to grow even more in the 21st century. Most of today’s energy demand comes from non-renewable energy sources like oil, coal, and natural gas. Combustion of these fossil fuels has harmful effects on the Earth’s ecosystem and is prominent contributors to the “greenhouse effect” accelerating global warming.
On the other hand, sun can provide almost unlimited amount of energy for all our future needs if we know how to harvest sunlight and store the solar energy in a cost efficient way. OSCs have an unlimited number of potential applications because of their possibility of being thin, flexible, and cheap.
Thin film based OSCs are rapidly growing and large-scale commercialization is on the way. In this Thesis, new organic materials were synthesized to overcome the main limitations of efficiency and stability of existing OSCs. Synthesis and spectroscopic studies of two different classes of molecules, namely, benzothiazole and perylene bisimide derivatives were done to check viability of their use in OSCs. When the newly synthesized materials were used in standard solar cell architecture, efficiency of ~ 4% reproducibly achieved (up to 41% improvement). Moreover, efficiencies of ~ 7% were also achieved but with lower reproducibility. Even though from manufacturing-to-handling of the solar cells were performed in open atmosphere, the lifetime of new OSCs were found to be almost one year.
These results indicate that it is imperative to synthesize compounds that match the solar spectrum, optimize the device architecture, and understand the photo-induced phenomena inside the thin-film structures.
The public defense on Friday, 25 May
The doctoral dissertation of MSc (Tech) Somnath Dey "Supramolecular Photochemistry" ("Benzothiazole and Perylene Bisimide Derivatives - Synthesis and Opto-Electronic Characterization") will be publicly examined at the Faculty of Science and Environmental Engineering of Tampere University of Technology in room Auditorium Pieni Sali 1in the Festia Building (address: Korkeakoulunkatu 8, Tampere, Finland) on Friday 25th of May 2012, at 12:00.
The opponent will be Professor Carita Kvarnström (Department of Chemistry, University of Turku). Prof. Helge Lemmetyinen of Department of Chemistry and Bioengineering (TUT) is the supervisor of this Thesis.
Somnath Dey (28) is from Chandannagar, India, and works as a researcher at Department of Chemistry and Bioengineering, TUT.
Further information: Somnath Dey, tel. 040 140 3617; E-mail: somnath.dey@tut.fi.