Change in electronic states before and after photo-irradiation at a Donor/Acceptor (D/A) interface in organic solar cells consisting of zinc-porphyrin and fullerene films has been examined using in situ impedance spectroscopy (IS), which makes it possible to non-destructively measure a built-in potential (Vbi) of both D and A films at the D/A interface. The accumulation of photo-generated carriers in the vicinity of the D/A interface was found to increase the Vbi of both D [Zn(OEP)] and A [C60] films at the interface. In addition, it was noted that the sum of Vbi obtained on photo-irradiation was in good agreement with the open-circuit voltage (VOC), of which the origin is still unsolved for organic solar cells. Thus, the charge accumulation of photo-generated carriers in the vicinity of the D/A interface plays a key role in determining V OC.
All Science Journal Classification (ASJC) codes
- Signal Processing
- General Physics and Astronomy
- Applied Mathematics
- Electrical and Electronic Engineering
- Computer Networks and Communications