2007 Fiscal Year Final Research Report Summary
Development of high-efficient three-layered organic solid-state solar cell
| Project/Area Number |
18560012
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Osaka University |
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Principal Investigator |
HIRAMOTO Masahiro Osaka University, Graduate School of Engineering, Associate Professor (20208854)
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| Project Period (FY) |
2006 – 2007
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| Keywords | p-i-n iunction organic solar cells / Ultra-high purification / seven-nine / conversion efficiency of 5.3% / 1000h operation / increase of open-circuit photoyoltage / fullerene / ZnO transparent electron transport layer |
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| Research Abstract |
(1) p-i-n organic solar cells having thick codeposited i-interlayer composed of metal-free phthalocyanine and fullerene were successfully fabricated by using fullerene purified seven-nine level (99.99999%) by means of the single-crystal formed sublimation. Fill factor of p-i-n cells hardly decreased even for extremely thick i-interlayer reaching 1200 nm. Short-circuit photocurrent density reached 19 mAcm^<-2> based on nearly 100% absorption of visible light in the solar spectrum by thick i-interlayer. As a result, the photo-electric conversion efficiency of 5.3% (world record) was obtained.
(2) Long-term operation tests of p-i-n organic solar cells were performed in various atmosphere. Under high vacuum (<10^<-7> Torr), p-i-n cell covered with Al-doped ZnO film acting as transparent electron transport layer was operated without degradation for 1000 hours (42 days).
(3) It has been confirmed that the attainable open-circuit photovoltage (V_<oc>) for organic photovoltaic cells consisting of co-deposited films is determined by the effective bandgap, namely, the energetic difference between the LUMO level of the n-type organic semiconductor and the HOMO level of the p-type organic semiconductor. The observed V_<oc> increased with increasing effective bandgap and exceeded 0.7 V.
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