Prof. Furong Zhu
Professor, Department of Physics, Hong Kong Baptist University, China.

Speech title: Organic photovoltaics: From light harvesting, charge recombination and collection perspectives

Abstract: This talk discusses the advances in organic solar cells (OSCs) and understanding of the charge recombination processes and charge collection, which underpin the optimum cell design and performance. The charge transport and recombination properties in the bulk heterojunction OSCs are investigated using the transient photocurrent and photo-induced charge extraction by linearly increasing voltage techniques. Combined with light intensity-dependent current density–voltage characteristic, it is found that the origin of unfavorable electron collection is mainly due to the trap-limited bimolecular recombination, resulting in the compensation of drifted photo-generated electrons at the organic/cathode interface. The undesired charge collection can be eliminated by inserting a thin metal oxide interlayer between the organic layer and electrode. Suppression of the metal oxide subgap states significantly improves the performance of OSCs.