Dependence of photocurrent generation on the crystalline phase of titanyl phthalocyanine film in heterojunction photovoltaic cells
We report that the photocurrent generation of a titanyl phthalocyanine (TiOPc) layer in heterojunction photovoltaic cells is strongly dependent on the crystalline phase of the TiOPc layer. Vacuum-deposited TiOPc films with an amorphous phase were changed into mixed crystalline films with two or thre...
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Published in | Japanese Journal of Applied Physics Vol. 54; no. 9; pp. 91601 - 91607 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
The Japan Society of Applied Physics
01.09.2015
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Online Access | Get full text |
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Summary: | We report that the photocurrent generation of a titanyl phthalocyanine (TiOPc) layer in heterojunction photovoltaic cells is strongly dependent on the crystalline phase of the TiOPc layer. Vacuum-deposited TiOPc films with an amorphous phase were changed into mixed crystalline films with two or three crystalline phases, Phase I and Phase II or Phase Y, by solvent vapor treatment with various solvents, which is confirmed from the ultraviolet-visible absorption spectra and X-ray diffraction patterns of solvent-vapor-treated TiOPc films. From the incident photon to current conversion efficiency (IPCE) measurement, it is clearly demonstrated that only the amorphous phase and Phase II but not Phase I nor Phase Y of TiOPc can contribute to photoelectric conversion in heterojunction photovoltaic cells. This result may come from the low charge generation (exciton dissociation) efficiency of Phase I and Phase Y crystalline structures, which was supported by the change in IPCE curves under inverse bias application. |
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ISSN: | 0021-4922 1347-4065 |
DOI: | 10.7567/JJAP.54.091601 |