CsPbBr₃钙钛矿单晶的制备及其光电探测器的研究
Preparation of CsPbBr₃ Perovskite Single Crystal and Research on Its Photodetector

与有机–无机杂化钙钛矿相比，全无机钙钛矿CsPbX₃ (X = Cl, Br, I)中A位不含有易于热挥发的有机阳离子，因此具有更高的稳定性。全无机钙钛矿单晶具有低的缺陷密度，高的载流子迁移率，因而被广泛地用于制备光电器件。然而传统制造CsPbBr₃单晶的方法，如布里奇曼熔融法、反温度结晶和反溶剂蒸汽辅助结晶等，往往依赖于高温、复杂工艺和真空环境。而且晶体质量相对较差，存在大量缺陷，严重影响器件性能。本研究工作中，我们使用了一种两段式升温法，通过缓慢蒸发溶剂控制钙钛矿在低温高质量成核，进而升高温度快速结晶生长，最终获得高质量的CsPbBr₃块状单晶。利用该CsPbBr₃钙钛矿单晶构建金属–半导体–金属结构的光电探测器，该器件展现出优异的光电性能，在1 V工作电压下，器件在540 nm处的响应度为2.68 × 10^？3 A？W^？1，在2 V电压下，光暗电流比可达2.23 × 10³。同时它展现了快速的响应时间(上升时间：8.3 μs；下降时间：684.9 μs)。
Compared with the organic-inorganic hybrid perovskite, the all-inorganic perovskite CsPbX₃ (X = Cl, Br, I) don’t contain organic cations that are prone to thermal volatilization, so it has higher stability. All-inorganic perovskite single crystals have low defect density and high carrier mobility, so they are widely used to prepare optoelectronic devices. However, traditional methods for manufacturing CsPbBr₃ single crystals, such as Bridgman method, inverse temperature crystallization, and anti-solvent vapor assisted crystallization, often rely on high temperatures, complex processes, and vacuum environments. Moreover, the crystal quality is relatively poor, and there are a large number of defects, which seriously affect the performance of the device. In this research, we used a two-stage heating method to control the high-quality nucleation of perovskite at low temperature by slowly evaporating the solvent, and then increasing the temperature to rapidly crystal growth, and finally obtaining high-quality CsPbBr₃ bulk single crystals. The CsPbBr₃ perovskite single crystal is used to construct a photodetector with a metal-semiconductor-metal structure. The device exhibits excellent photoelectric performance. Under a bias of 1 V, the response of the device at 540 nm is 2.68 × 10^？3 A？W^？1. Under the bias of 2 V, the ratio of light to dark current is 2.23 × 10³. At the same time, it exhibits a fast response time (rise time: 8.3 μs; fall time: 684.9 μs).