Numerical Simulation of S-Shaped Current–Voltage Curves Induced by Electron Traps in Inverted Organic Photovoltaics |
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Authors: | Shanglin Luo Mingfang Huo Qin Xue Guohua Xie |
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Affiliation: | 1.Department of Physical Science and Technology, Central China Normal University, Wuhan 430079, China; (S.L.); (M.H.);2.Sauvage Center for Molecular Sciences, Hubei Key Lab on Organic and Polymeric Optoelectronics Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China |
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Abstract: | Organic photovoltaics (OPVs) differ from their inorganic counterparts because of inevitable electronic disorders and structural heterogeneity. Charge carrier traps are inevitable in organic semiconductors. A common failure mechanism of OPVs is the development of an S-shaped current density–voltage characteristic (J-V curve). Herein, we focus on investigating the underlying physical mechanism of S-shaped deformation of J-V curve of the inverted organic photovoltaic devices with bulk-heterojunction, proven by experiments with the n-doped electron extraction layer and numerical simulations assuming electron traps (0.1 eV deeper) in the electron extraction layer. The numerical simulations are quite consistent with the experimental results. In addition, the open circuit voltage induced by S-kink is exemplified to be enhanced after removing the electron traps in the interlayer by introducing a dopant of cesium carbonate. |
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Keywords: | organic photovoltaics, current– voltage, electron traps, numerical simulation |
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