writer：J. H. Lee, D. W. Kim, H. Jang, J. K. Choi, J. Geng, J. W. Jung, S. C. Yoon, H.-T. Jung,*
keywords：anodic aluminum oxide, bulk heterojunctions,nanoimprinting,photovoltaic devices,solar cells
source：期刊
specific source：Small 2009, 5(19), 2139-2143
Issue time：2009年

Enhancing power conversion efficiency (PCE) is one of the most important goals in the design of new polymer-based photovoltaic cells. Printable photovoltaic cells make it possible to realize economically affordable solar energy conversion systems.[1,2] The most highly studied organic photovoltaic devices consist of a mixture of polythiophene derivatives (donor) and fullerenes (acceptor) as a single, bulk-heterojunction active layer. The active layer components are spontaneously phase-separated into interconnected domains and the photocurrent is caused by diffusion of photogenerated excitons across the donor–acceptor heterojunction interface. Electron transfer then occurs between the donor and acceptor and charge carriers are transported through the interconnected domains.[3,4] However, owing to its disordered nature, the bulkheterojunction system has many dead ends (donor or acceptor domains those are isolated and not connected with the electrodes) and a long conduction path that leads to low PCE.