Thermochromic materials have recently attracted great attention due to their controllable and rich physicochemical properties. However, until now, no studies have been reported on thermochromic materials for photovoltaic and optoelectronic applications. Here we report a new lead-free hybrid semiconductor material, (C₁₆H₂₀N₂)SbBr₅ (1), which adopts the zero-dimensional (0-D) perovskite-type inorganic framework. Strikingly, the thermochromism in 1 leads to a wide tunable bandgap and superior photoelectric properties. Three distinct color-varying stages were first observed, i.e. colorless to yellow (I), yellow to red (II), and red to black brown (III). In particular, the figure-of-merits for thin-film photodetectors based on II-thermochromism were greatly improved, with the dark current lowered to one quarter and light photocurrent enhanced at least 12-fold. The photocurrent on/off switching ratio was thus improved by ∼50 times through thermochromism. As a new conceptual strategy to engineer the optical bandgap and meet specific photoelectric functions, our study paves the way for building high-performance optoelectronic devices based on thermochromic materials.

中文翻译：

---

热致变色可调节无铅钙钛矿型混合半导体的光学带隙，以有效增强光电流的产生

热变色材料由于其可控的和丰富的物理化学特性，最近引起了极大的关注。然而，到目前为止，还没有关于用于光伏和光电应用的热致变色材料的研究的报道。在这里，我们报告了一种新的无铅杂化半导体材料（C ₁₆ H ₂₀ N ₂）SbBr ₅（1），它采用了零维（0-D）钙钛矿型无机骨架。引人注目的是，1中的热致变色导致宽的可调带隙和出众的光电性能。首先观察到三个不同的变色阶段，即无色至黄色（I），黄色至红色（II）和红色至黑褐色（III）。尤其是，基于II热变色的薄膜光电探测器的品质因数得到了极大的改善，暗电流降低到四分之一，光电流提高了至少12倍。因此，通过热致变色，光电流通/断切换比提高了约50倍。作为设计光学带隙并满足特定光电功能的新概念策略，我们的研究为构建基于热致变色材料的高性能光电器件铺平了道路。