Ye Fei, Wu Haodi, Qin Minchao, Yang Shuo, Niu Guangda, Lu Xinhui, Wang Jiannong, Mitzi David B, Choy Wallace C H
Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Pokfulam, Hong Kong SAR, China.
Wuhan National Laboratory, Huazhong University of Science and Technology, Wuhan, Hubei Province 430074, China.
ACS Appl Mater Interfaces. 2020 May 27;12(21):24498-24504. doi: 10.1021/acsami.0c04516. Epub 2020 May 14.
Though CHNHPbBr single crystals are frequently applied in various optoelectronic devices due to their favorable cuboid geometry, superior optoelectronic properties, and better stability than CHNHPbI, CHNHPbBr polycrystalline films normally show poorer morphology with scattered crystals than their iodide counterparts, inherently due to their different crystallization habits. In this work, a facile process based on a hot methylamine-based precursor with high viscosity and concentration is demonstrated to counteract rapid ion diffusion. The precursor also has special features including a large colloidal size, a solid form at room temperature, and fast crystallization offered by the easy evacuation of methylamine. CHNHPbBr films composed of tightly aligned CHNHPbBr cuboids on micron scale are obtained. Wide channel (100 μm) photodetectors made from the CHNHPbBr films show promising photoresponse and fast response speeds on par with those based on single crystals, suggesting high film quality and good optoelectronic connections between neighboring cuboids.
尽管CHNHPbBr单晶因其良好的长方体几何形状、优异的光电性能以及比CHNHPbI更好的稳定性而经常应用于各种光电器件中，但CHNHPbBr多晶薄膜通常比其碘化物对应物表现出更差的形态，晶体分散，这本质上是由于它们不同的结晶习性。在这项工作中，展示了一种基于具有高粘度和浓度的热甲胺基前驱体的简便工艺，以抵消快速的离子扩散。该前驱体还具有特殊特性，包括大的胶体尺寸、室温下的固体形式以及通过甲胺的容易抽空提供的快速结晶。获得了由微米级紧密排列的CHNHPbBr长方体组成的CHNHPbBr薄膜。由CHNHPbBr薄膜制成的宽通道（100μm）光电探测器表现出有前景的光响应和与基于单晶的探测器相当的快速响应速度，这表明薄膜质量高且相邻长方体之间具有良好的光电连接。
