New light is shed on the previously known perovskite material, Cs₂Au₂I₆, as a potential active material for high‐efficiency thin‐film Pb‐free photovoltaic cells. First‐principles calculations demonstrate that Cs₂Au₂I₆ has an optimal band gap that is close to the Shockley–Queisser value. The band gap size is governed by intermediate band formation. Charge disproportionation on Au makes Cs₂Au₂I₆ a double‐perovskite material, although it is stoichiometrically a single perovskite. In contrast to most previously discussed double perovskites, Cs₂Au₂I₆ has a direct‐band‐gap feature, and optical simulation predicts that a very thin layer of active material is sufficient to achieve a high photoconversion efficiency using a polycrystalline film layer. The already confirmed synthesizability of this material, coupled with the state‐of‐the‐art multiscale simulations connecting from the material to the device, strongly suggests that Cs₂Au₂I₆ will serve as the active material in highly efficient, nontoxic, and thin‐film perovskite solar cells in the very near future.

中文翻译：

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混合价钙钛矿Cs2Au2I6：一种超高效薄膜无铅光伏电池的潜在材料

以前已知的钙钛矿材料Cs ₂ Au ₂ I ₆有了新的亮点，它是高效薄膜无铅光伏电池的潜在活性材料。第一性原理计算表明，Cs ₂ Au ₂ I ₆的最佳带隙接近于Shockley-Queisser值。带隙大小受中间带形成的支配。尽管化学计量上是单钙钛矿，但Au上的电荷歧化使Cs ₂ Au ₂ I ₆成为双钙钛矿材料。与大多数先前讨论过的双钙钛矿相反，Cs ₂ Au ₂ I₆具有直接带隙特征，光学模拟预测非常薄的活性材料层足以使用多晶薄膜层实现高光转换效率。这种材料已经被证实的可合成性，再加上从材料到设备的最新多尺度模拟，强烈表明Cs ₂ Au ₂ I ₆将作为高效材料，无毒和可再生的活性材料。薄膜钙钛矿太阳能电池在不久的将来。