Silver Ions Assisted Inversion Temperature Crystallization of 2D Cs3Bi2Br9 Nanoflakes for Highly Sensitive X-Ray Detection |
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Authors: | Zhi Zheng Haiyang Li Liang Hai Ruiqi Ma Rui Liu Chunpeng Zhai Zongdong Sun Fei Wang Ying Ma Qingguo Xie Xiaoding Lou Tianyou Zhai Fan Xia |
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Affiliation: | 1. State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of the Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074 P. R. China;2. State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074 P. R. China;3. Department of Biomedical Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074 P. R. China |
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Abstract: | 2D perovskites have attracted wide attention for optoelectronic applications because of their unique layer structure and tunable outstanding optical/electrical properties. In addition, 2D Cs3Bi2Br9 nanoflakes possess large effective atomic number, high resistivity, high density as well as excellent stability, rendering it a promising material for X-ray detection. Nevertheless, it is full of challenges to synthesize 2D Cs3Bi2Br9 nanoflakes by conventional inversion temperature crystallization (ITC) strategy due to the existence of Br- vacancies in the Cs3Bi2Br9 crystal nucleus. Herein, an Ag+ assisted ITC (SAITC) strategy to grow 2D Cs3Bi2Br9 nanoflakes is proposed. The synthesis mechanism revealed by both experiments and theoretical calculations can be mainly ascribed to the passivated Br− vacancies and enhanced structure stability by adding Ag+ which can effectively prevent the oxidation of 2D Cs3Bi2Br9 nanoflakes from growth of hybrid crystals. The synthesized high-crystallinity 2D Cs3Bi2Br9 nanoflakes possess direct bandgap characteristic, and the mobility lifetime can reach 9.8 × 10−4 cm2 V−1. Excitingly, the fabricated device based on 2D Cs3Bi2Br9 nanoflakes demonstrates ultrahigh sensitivity of detecting X-ray (1.9 CGyair−1cm−2) at very low driven voltage (0.5 V) due to the photoconductive gain mechanism. The 2D Cs3Bi2Br9 nanoflakes synthesized by SAITC method have great potential for developing highly sensitive optoelectronic devices. |
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Keywords: | 2D perovskites Cs3Bi2Br9 nanoflakes inversion temperature crystallization metal cations |
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