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arXiv · 2101.02545

Dark Self-Healing Mediated Negative Photoconductivity of Lead-Free Cs3Bi2Cl9 Perovskite Single Crystal

Naveen Kumar Tailor·Partha Maity·Makhsud Saidaminov·Narayan Pradhan·Soumitra Satapathi
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Abstract

Halide perovskites are recently emerged as one of the frontline optoelectronic materials for device applications and have been extensively studied in past few years. Among these while, lead-based materials were most widely explored, investigation of optical properties of lead-free perovskites is limited. Being optically active, these materials were expected to show light-induced enhanced photoconductivity and the same was reported for lead halide perovskite single crystals. However, on contrary, herein, light-induced degradation of bismuth halide perovskite Cs3Bi2Cl9 single crystals is reported which was evidenced by negative photoconductivity with slow recovery. The femtosecond transient reflectance (fs-TR) spectroscopy studies further revealed these electronic transport properties were due to the formation of light-activated metastable trap states within the perovskite crystal. The figure of merits of Cs3Bi2Cl9 single-crystal detectors such as responsivity (17 mA/W), detectivity (6.23 X 10power 11 Jones) and the ratio of current in dark to light (~7160) was calculated and it is found that they are comparable or higher to reported perovskite single crystals based positive photodetectors. This observation for lead-free perovskite single crystals which were optically active but showed retroactive photocurrent on irradiation remained unique for such materials.

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Naveen Kumar Tailor, Partha Maity, Makhsud Saidaminov, Narayan Pradhan, Soumitra Satapathi. 2021-01-07. Dark Self-Healing Mediated Negative Photoconductivity of Lead-Free Cs3Bi2Cl9 Perovskite Single Crystal. https://doi.org/10.1021/acs.jpclett.1c00057

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