Abstract Self-powered, all-inorganic photodetectors (PDs) have attracted ever-increasing research attention recently, because of their upgraded stability, promising performance, and free of external power supply. However, most of the inorganic perovskite films used for such PDs are prepared by solution methods, for which the crystal sizes vary significantly among different areas. This issue is more serious among different samples and eventually stands a substantial hindrance to PDs’ applications. In this paper, we introduced an amount of polyethyleneimine (PEI) species into the CsPbIBr2 precursor, which enabled a thin film with the homogeneous grain growth. Moreover, with the PEI modification, the conduction band energy level of resulting CsPbIBr2 film was also reduced, which leads to a more favored interfacial energy alignment between it and the TiO2 electron transporting layer (ETL). Consequently, the champion PD yielded the dark current of 3.12 × 10−10 A, the peak responsivity (R) of 0.20 A/W, the maximum specific detectivity (D*) of 6.01 × 1012 Jones, and the response time of 2.07 μs, which are far beyond those of the one prepared without PEI additive.

中文翻译：

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用于高效自供电全无机光电探测器的 CsPbIBr2 薄膜的偶极子模板均匀晶粒生长

摘要 自供电全无机光电探测器（PDs）由于其稳定性提升、性能优越、无需外部电源等优点，近年来受到越来越多的研究关注。然而，大多数用于此类PD的无机钙钛矿薄膜是通过溶液法制备的，其晶体尺寸在不同区域之间存在显着差异。这个问题在不同的样本中更为严重，最终会严重阻碍 PD 的应用。在本文中，我们将一定量的聚乙烯亚胺 (PEI) 物质引入 CsPbIBr2 前体中，这使得薄膜具有均匀的晶粒生长。此外，通过 PEI 改性，所得 CsPbIBr2 薄膜的导带能级也降低，这导致它与 TiO2 电子传输层 (ETL) 之间更有利的界面能量排列。因此，冠军 PD 产生了 3.12 × 10−10 A 的暗电流、0.20 A/W 的峰值响应度 (R)、6.01 × 1012 Jones 的最大比检测率 (D*) 和 2.07 μs 的响应时间，远远超过没有 PEI 添加剂制备的那些。