The role of [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as an n-type homologue buffer layer (HBL) was investigated in a bulk-heterojunction solar cell. The n-type HBL was inserted between the photoactive layer and the cathode. We found that the n-type HBL formed an ideal contact between the photoactive layer and the cathode, enhancing the rectifying ability of the device. In addition, the enlarged donor/acceptor interface between the bulk-heterojunction layer and the n-type HBL generated an additional photocurrent through an interdiffusion phenomenon. A device with the controlled n-type HBL (30 nm) had an enhanced power conversion efficiency of nearly 40% compared to the reference device.
Bibliographical noteFunding Information:
This work is supported by a National Research Foundation of Korea (NRF) grant ( 2012-0008721 and 2011-0022765 ) funded by the government of Korea (MEST). T. I. Lee and J. M. Myoung were supported by the WCU (World Class University) program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology ( R32-20031 ).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films