Charge Transport and Recombination in Organic Photovoltaic Devices

pivrikas_graphic

Speaker: Assistant Professor Almantas Pivrikas
Date: 26th March 2010

Organic electronics has become a broad scientific field attracting large academic and industrial interest. The main advantage of organic electronics is the possibility to achieve the desired photophysical and mechanical device properties by designing novel materials through chemical synthesis. Solution processing techniques allow for large area and low cost device production with novel form factors and aesthetic appearances.

Organic solar cells and organic light emitting diodes have shown to be competitive to present technologies since they already are commercial available on the market. One of the major goals of scientific community working in the field of organic photovoltaic devices is to improve and understand the power conversion efficiency limiting mechanisms in organic solar cells. In my presentation I will describe the factors that limit power conversion efficiencies in excitonic solar cells. The relation between efficient light absorption, mobile charge generation, charge transport to the electrodes and charge carrier recombination will be described. The charge carrier mobility times bimolecular recombination coefficient (carrier lifetime) product is used to demonstrate film thickness dependent maximum achievable power conversion efficiency. Finally, strategies, which enable us to overcome the efficiency limiting processes and improve the photovoltaic performance of organic solar cells will be discussed.