Structural influences on charge carrier dynamics for small-molecule organic photovoltaics

Journal Article · Mon Jul 07 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4887076· OSTI ID:22306243

Wang, Zhiping; Shibata, Yosei; Yamanari, Toshihiro; Matsubara, Koji; Yoshida, Yuji ^[1]; Miyadera, Tetsuhiko ^[1]; Saeki, Akinori; Seki, Shu ^[2]; Zhou, Ying ^[3]

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1. Research Center for Photovoltaic Technologies, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, 305-8565 Tsukuba (Japan)
2. Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, 565-0871 Suita, Osaka (Japan)
3. Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, 305-8565 Tsukuba (Japan)

We investigated the structural influences on the charge carrier dynamics in zinc phthalocyanine/fullerene (ZnPc/C{sub 60}) photovoltaic cells by introducing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and 2,5-bis(4-biphenylyl)-bithiophene (BP2T) between indium tin oxide and ZnPc layers. ZnPc films can be tuned to be round, long fiber-like, and short fiber-like structure, respectively. Time-resolved microwave conductivity measurements reveal that charge carrier lifetime in ZnPc/C{sub 60} bilayer films is considerably affected by the intra-grain properties. Transient photocurrent of ZnPc single films indicated that the charge carriers can transport for a longer distance in the long fiber-like grains than that in the round grains, due to the greatly lessened grain boundaries. By carefully controlling the structure of ZnPc films, the short-circuit current and fill factor of a ZnPc/C{sub 60} heterojunction solar cell with BP2T are significantly improved and the power conversion efficiency is increased to 2.6%, which is 120% larger than the conventional cell without BP2T.

• OSTI ID: 22306243
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHARGE CARRIERS
CURRENTS
EFFICIENCY
ELECTRICAL FAULTS
FILL FACTORS
FILMS
FULLERENES
GRAIN BOUNDARIES
HETEROJUNCTIONS
LAYERS
LIFETIME
MOLECULES
PHOTOVOLTAIC EFFECT
PHTHALOCYANINES
SOLAR CELLS
TIME RESOLUTION
TRANSIENTS
ZINC COMPLEXES