Intrinsic near‐infrared response of silicon‐based photodetectors can cause undesirable noise and thus undermine performance in visible‐light applications. All‐inorganic perovskite CsPbIxBr3–x with the absorption cutoff at ≈720 nm shows significant potential in visible‐light photodetection. However, its poor phase stability and high defect density on surfaces of polycrystalline films significantly impairs its performance. Constructing low‐dimension/3D heterostructure atop CsPbIxBr3–x is an effective way to simultaneously address stability and defect challenges. Herein, a facile and universal strategy is demonstrated to construct 2D PEA2PbI2Br2/quasi‐2D PEA2CsPb2I5Br2/3D CsPbIxBr3–x heterostructures by two‐step sequential surface treatment with phenylethylammonium bromide (PEABr). The PEABr pre‐treatment in the first step favors the volatilization of dimethylammonium iodide to produce higher phase stability. With the addition of strong‐polarity methanol in the solution for the second treatment, PEABr can easily react with the PbIxBr2–x rich surface to form low‐dimensional/3D perovskites heterostructure. Resultant heterostructure‐based photodetectors achieve superior performance in photodiode‐type photodetectors and enhanced stability, specifically a champion external quantum efficiency of 84% and detectivity of 3.1 × 1012 Jones at 690 nm, and linear dynamic range of 163 dB. Finally, the visible‐light imaging is demonstrated. This work offers a universal approach to realize CsPbIxBr3–x heterostructures and stimulates infrared‐blind visible‐light applications.

中文翻译：

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用于高性能红外盲可见光光电探测器的 2D/准 2D/3D CsPbIxBr3–x 垂直异质结构面向成像应用


硅基光电探测器的固有近红外响应会导致不需要的噪声，从而破坏可见光应用的性能。在 ≈720 nm 处具有吸收截止值的全无机钙钛矿 CsPbIxBr3–x 在可见光光检测中显示出巨大的潜力。然而，其较差的相稳定性和多晶薄膜表面的高缺陷密度严重损害了其性能。在 CsPbIxBr3–x 上构建低维/3D 异质结构是同时解决稳定性和缺陷挑战的有效方法。在此，通过用苯乙基溴化铵 （PEABr） 的两步顺序表面处理，展示了一种简单而通用的策略来构建 2D PEA2PbI2Br2/准 2D PEA2CsPb2I5Br2/3D CsPbIxBr3–x 异质结构。第一步的 PEABr 预处理有利于二甲基碘化铵的挥发，以产生更高的相稳定性。在溶液中添加强极性甲醇进行第二次处理后，PEABr 可以很容易地与富含 PbIxBr2–x 的表面反应，形成低维/3D 钙钛矿异质结构。由此产生的基于异质结构的光电探测器在光电二极管型光电探测器中实现了卓越的性能和增强的稳定性，特别是在 690 nm 处实现了 84% 的冠军外部量子效率和 3.1 × 1012 Jones 的探测率，以及 163 dB 的线性动态范围。最后，演示了可见光成像。这项工作提供了一种实现 CsPbIxBr3-x 异质结构的通用方法，并刺激了红外-盲-可见光应用。