Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588-0656, USA.
Department of Applied Physical Sciences, University of North Carolina, Chapel Hill, NC, 27599, USA.
Adv Mater. 2017 Oct;29(39). doi: 10.1002/adma.201703209. Epub 2017 Aug 28.
Organic-inorganic halide perovskites are promising photodetector materials due to their strong absorption, large carrier mobility, and easily tunable bandgap. Up to now, perovskite photodetectors are mainly based on polycrystalline thin films, which have some undesired properties such as large defective grain boundaries hindering the further improvement of the detector performance. Here, perovskite thin-single-crystal (TSC) photodetectors are fabricated with a vertical p-i-n structure. Due to the absence of grain-boundaries, the trap densities of TSCs are 10-100 folds lower than that of polycrystalline thin films. The photodetectors based on CH NH PbBr and CH NH PbI TSCs show low noise of 1-2 fA Hz , yielding a high specific detectivity of 1.5 × 10 cm Hz W . The absence of grain boundaries reduces charge recombination and enables a linear response under strong light, superior to polycrystalline photodetectors. The CH NH PbBr photodetectors show a linear response to green light from 0.35 pW cm to 2.1 W cm , corresponding to a linear dynamic range of 256 dB.
有机-无机卤化物钙钛矿由于其强吸收、大载流子迁移率和易于调谐的带隙，是很有前途的光电探测器材料。到目前为止，钙钛矿光电探测器主要基于多晶薄膜，但其存在一些不理想的性质，例如大的缺陷晶界阻碍了探测器性能的进一步提高。在这里，采用垂直的 p-i-n 结构制备了钙钛矿薄单晶（TSC）光电探测器。由于不存在晶界，TSC 的陷阱密度比多晶薄膜低 10-100 倍。基于 CH NH PbBr 和 CH NH PbI TSCs 的光电探测器的噪声低至 1-2 fA Hz ，产生了 1.5 × 10 cm Hz W 的高特定探测率。不存在晶界减少了电荷复合，并使在强光下能够具有线性响应，优于多晶光电探测器。CH NH PbBr 光电探测器对 0.35 pW cm 至 2.1 W cm 的绿光具有线性响应，对应于 256 dB 的线性动态范围。
