ABSTRACT The perovskite cesium lead halides have been proposed as promising materials for photovoltaic devices because of their visible light absorption and direct band gap semiconductors. The structural, electronic and optical properties of the bulk CsPbX3 (X = Br, Cl and I) are studied, using density functional theory. In order to use these compounds in photovoltaic applications, the only inconvenient of these materials is that they have a slightly high gap energy value such as: 2.57, 2.16 and 1.88 eV for CsPbCl3, CsPbBr3 and CsPbI3 compounds, respectively. It is known that the efficiency of the solar cells varied with the band gap of the materials used. Moreover, by applying 3% of strain on the perovskite CsPbX3, we have reducing the gap energy value of these materials. The present compounds are one of the promising candidates for photovoltaic applications.

中文翻译：

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应变效应如何降低 CsPbX3 钙钛矿化合物的带隙能量？

摘要钙钛矿铯铅卤化物由于其可见光吸收和直接带隙半导体而被认为是有前途的光伏器件材料。使用密度泛函理论研究了块状 CsPbX3（X = Br、Cl 和 I）的结构、电子和光学特性。为了在光伏应用中使用这些化合物，这些材料的唯一不便之处在于它们的间隙能量值略高，例如：CsPbCl3、CsPbBr3 和 CsPbI3 化合物分别为 2.57、2.16 和 1.88 eV。众所周知，太阳能电池的效率随所用材料的带隙而变化。此外，通过在钙钛矿 CsPbX3 上施加 3% 的应变，我们降低了这些材料的间隙能值。