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Fast Charge Diffusion in MAPb(I1–xBrx)3 Films for High-Efficiency Solar Cells Revealed by Ultrafast Time-Resolved Reflectivity
journal contribution
posted on 2019-03-13, 00:00 authored by Wenjun Shi, Yong Wang, Taiyang Zhang, Haijuan Zhang, Yixin Zhao, Jie ChenOrganometallic halide
perovskite solar cells such as MAPbI3 have shown great
promise as a low-cost, high-efficiency photovoltaic
candidate. Recent studies demonstrated that by substituting an appropriate
amount I ions of MAPbI3 with Br ions, the device performance
parameters, such as moisture stability or power conversion efficiency,
can be further optimized. In this study, using time-resolved optical
reflectivity to track the carrier dynamics in MAPb(I1–xBrx)3 films
with different Br contents, we found that photocarriers in MAPb(I1–xBrx)3 films with x = 0.01 and 0.02 diffuse much
faster than those in films with other Br contents. We suggest that
the faster charge carrier diffusion benefits from larger crystal grain
size. As a result, this suppresses electron and hole recombination
and increases the carrier extraction efficiency, in agreement with
the higher power conversion efficiency reported previously.
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Br contentshigh-efficiency photovoltaic candidateFast Charge Diffusion3 filmsdevice performance parameterscrystal grain sizeMAPbI 3charge carrier diffusion benefitscarrier extraction efficiencypower conversion efficiencyUltrafast Time-Resolved Reflectivity Organometallic halide perovskiteHigh-Efficiency Solar Cells Revealed