- 著者
- Yonezawa Kouhei Kamioka Hayato Yasuda Takeshi Han Liyuan Moritomo Yutaka
- 出版者
- American Institute of Physics
- 雑誌
- Applied physics letters (ISSN:00036951)
- 巻号頁・発行日
- vol.103, no.17, pp.173901, 2013-10
- 被引用文献数
- 9 1
By means of femto-second time-resolved spectroscopy, we investigated the carrier formation process against film morphology and temperature (T) in highly-efficient organic photovoltaic, poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5- ] dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b] thiophenediyl]] (PTB7)/[6,6]-phenyl -butyric acid methyl ester solar cells. We found that the carrier formation efficiency ( ) from an absorbed photon is nearly independent of the film morphology, indicating that the internal quantum efficiency ( ) is mainly governed by the carrier transfer efficiency ( ) to the electrodes. The activation energy ( ) of is significantly low, which suggests an extended charge-transfer state around the PTB7/PC70BM interface.