TY  - JOUR
UR  - https://doi.org/10.1063/1.4970958
Y1  - 2016/12/07/
PB  - AMER INST PHYSICS
N2  - Modeling the charge-generation process is highly important to understand device physics and optimize power conversion efficiency of bulk-heterojunction organic solar cells (OSCs). Free carriers are generated by both ultrafast exciton delocalization and slow exciton diffusion and dissociation at the heterojunction interface. In this work, we developed a systematic numerical simulation to describe the charge-generation process by a modified drift-diffusion model. The transport, recombination, and collection of free carriers are incorporated to fully capture the device response. The theoretical results match well with the state-of-the-art high-performance organic solar cells. It is demonstrated that the increase of exciton delocalization ratio reduces the energy loss in the exciton diffusion-dissociation process, and thus, significantly improves the device efficiency, especially for the short-circuit current. By changing the exciton delocalization ratio, OSC performances are comprehensively investigated under the conditions of short-circuit and open-circuit. Particularly, bulk recombination dependent fill factor saturation is unveiled and understood. As a fundamental electrical analysis of the delocalization mechanism, our work is important to understand and optimize the high-performance OSCs.
TI  - Exciton delocalization incorporated drift-diffusion model for bulk-heterojunction organic solar cells
JF  - Journal of Applied Physics
N1  - This version is the version of record. For information on re-use, please refer to the publisher?s terms and conditions.
VL  - 120
ID  - discovery10053970
AV  - public
A1  - Wang, ZS
A1  - Sha, WEI
A1  - Choy, WCH
SN  - 0021-8979
EP  - 7
IS  - 21
ER  -