- 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.
- 著者
- Akaba Takahiro 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.102, no.13, pp.133901, 2013-04
- 被引用文献数
- 11
We investigated carrier formation dynamics in a small-molecular bulk heterojunction solar cell, 2,5-di-(2-ethylhexyl)-3,6-bis-(5″-n-hexy-[2,2′,5′,2″]terthiophen-5-yl)-pyrrolo[3,4-c]pyrrolo-1,4-dione/[6,6]-phenyl C71-butyric acid methyl ester, with low bandgap (Egap ≈ 1.5 eV). The photoinduced absorption (PIA) spectra of the blend film were decomposed into three PIAs, i.e., those due to donor exciton (D*), acceptor exciton (A*), and mobile carrier (D+). The analysis revealed carrier conversion from D* with a conversion time of ∼1.3 ps.
- 著者
- Matsuda Tomoyuki Kim Jungeun Moritomo Yutaka
- 出版者
- The Royal Society of Chemistry
- 雑誌
- RSC Advances (ISSN:20462069)
- 巻号頁・発行日
- vol.2011, no.9, pp.1716-1720, 2011-11
- 被引用文献数
- 9 1
We investigated the thermal expansion properties of metal nitroprussides, MA[Fe(CN)5NO]·zH2O (MA = Mn, Fe, Co, Ni, Cu, Zn, and Cd), which have various network structures, i.e. three-dimensional (3D) cubic (Fm[3 with combining macron]m for MA = Fe, Co, and Ni), distorted three-dimensional (distorted-3D) orthorhombic (Pnma for MA = Mn, Zn, and Cd), and two-dimensional (2D) orthorhombic (Amm2 for MA = Cu) structures. In the cubic system, in which the unbridged NO groups are randomly distributed, isotropic positive thermal expansion was observed. On the contrary, in the orthorhombic system, in which the unbridged NO groups are uniaxially distributed, positive (negative) thermal expansion was observed along (perpendicular to) the uniaxial direction. We interpreted the characteristic thermal responses in terms of the rotational vibrations of the [Fe(CN)5NO] units as well as their steric hindrances due to the network dimensionality.