Wang Rendong, Li Zhao, Li Shutao, Wang Pengfei, Xiu Junshan, Wei Gongxiang, Liu Huiqiang, Jiang Ning, Liu Yunyan, Zhong Mianzeng
School of Physics and Optoelectronic Engineering, Shandong University of Technology, Zibo, Shandong 255049, China.
Hunan Key Laboratory of Super-Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, China.
ACS Appl Mater Interfaces. 2020 Sep 16;12(37):41919-41931. doi: 10.1021/acsami.0c05754. Epub 2020 Sep 4.
All-inorganic cesium lead-halide perovskites exhibit a great development prospect in optoelectronic devices owing to their stability and remarkable optoelectronic properties. Herein, we investigate the solution-processed synthesis of perovskite CsPbBr nanosheets by using aqueous and ethanol as solvents. The results show that the aqueous environment ensures the phase formation of CsPbBr and that the supersaturated solution in ethanol boosts nucleation of the nanosheets. The substrate temperature is the key factor for the evolution of morphology and the variation of the thickness of CsPbBr nanosheets. Lower substrate temperature (<35 °C) is conducive to the formation of evenly distributed nanosheets with less stacking. The spatial and time-resolved fluorescence spectra indicate the heterogeneity of the defect density and the recombination process in different nanosheet regions. The photodetector based on the prepared CsPbBr nanosheet displays an excellent switching current ratio (9 × 10), a short rise and decay time (43 and 83 ms, respectively), and good stability (75% of the initial current after 90 days in air). In addition, the mechanical stability and flexibility of the photodetector on the flexible substrate are investigated for 500 bending cycles.
全无机铯铅卤化物钙钛矿因其稳定性和卓越的光电性能，在光电器件领域展现出巨大的发展前景。在此，我们研究了以水和乙醇为溶剂，通过溶液法合成钙钛矿CsPbBr纳米片。结果表明，水环境确保了CsPbBr的相形成，而乙醇中的过饱和溶液促进了纳米片的成核。衬底温度是影响CsPbBr纳米片形态演变和厚度变化的关键因素。较低的衬底温度（<35°C）有利于形成堆叠较少、分布均匀的纳米片。空间和时间分辨荧光光谱表明不同纳米片区域的缺陷密度和复合过程存在异质性。基于所制备的CsPbBr纳米片的光电探测器表现出优异的开关电流比（9×10）、较短的上升和衰减时间（分别为43和83毫秒）以及良好的稳定性（在空气中放置90天后，初始电流仍保留75%）。此外，还对柔性衬底上的光电探测器进行了500次弯曲循环的机械稳定性和柔韧性研究。
