The inherent ion migration in metal halide perovskite materials is known to induce deleterious and highly unstable dark currents in X‐ and γ‐ray detectors based on those compounds upon bias application. Dark current slow drift with time is identified as one of the major drawbacks for these devices to satisfy industrial requirements. Because dark current establishes the detectability limit, current evolution, and eventual growth may mask photocurrent signals produced by incoming X‐ray photons. Relevant information for detector assessment is ion‐related parameters such as ion concentration, ion mobility, and ionic space‐charge zones that are eventually built near the outer contacts upon detector biasing. A combined experimental (simple measurement of dark current transients) and 1D numerical simulation method is followed here using single‐crystal and microcrystalline millimeter‐thick methylammonium‐lead bromide that allows extracting ion mobility within the range of µion ≈ 10−7 cm2 V−1 s−1, while ion concentration values approximate Nion ≈ 1015 cm−3, depending on the perovskite crystallinity.

中文翻译：

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通过短路瞬态电流和数值模拟研究金属卤化物钙钛矿中的离子迁移和空间电荷区


众所周知，金属卤化物钙钛矿材料中固有的离子迁移会在基于这些化合物的 X 射线和 γ 射线探测器中在施加偏压时产生有害且高度不稳定的暗电流。暗电流随时间缓慢漂移被认为是这些器件满足工业要求的主要缺点之一。由于暗电流确定了可检测性极限，因此电流演变和最终生长可能会掩盖传入 X 射线光子产生的光电流信号。探测器评估的相关信息是与离子相关的参数，例如离子浓度、离子迁移率和离子空间电荷区，这些参数最终在探测器偏置时在外部触点附近建立。这里使用单晶和微晶毫米厚的甲基铵-溴化铅，采用组合实验（暗电流瞬变的简单测量）和一维数值模拟方法，可以提取 µion ≈ 10−7 cm2 V−1 范围内的离子淌度s−1，而离子浓度值近似 Nion ≈ 1015 cm−3，具体取决于钙钛矿结晶度。