Probing Charge Transfer Dynamics in All-organic Solar Cell Blends

Abstract

Organic photovoltaics are a promising source of energy for the future generations. Commercially successful organic solar cells of today use fullerene derivatives as acceptors, or p-type materials. However, if the cost of solar derived electricity is to be brought down, and organic solar cell materials are to be used for this purpose, then we will have to move away from fullerenes and be able to fabricate polymer – polymer blend devices. In this project, we aim at replacing fullerene derivative acceptors from successful polymer – fullerene solar cell blends. The underlying mechanisms of charge transfer between donor and acceptor polymers are understood through transient absorption spectroscopy. When successful charge transfer is observed, all-polymer organic solar cell devices are fabricated and efficiency studies are carried out on them. Results indicate that more extensive optimisation of blend films is required in terms of thickness, morphology, solvent of film casting etc. in order to derive high efficiencies.