Bandgap Engineering of Lead-Free Double Perovskite Cs2AgBiBr6 through Trivalent Metal Alloying
Bandgap Engineering of Lead-Free Double Perovskite Cs2AgBiBr6 through Trivalent Metal Alloying
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DOI：
10.1002/anie.201703970
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发表时间：
2017-07-03
影响因子：
16.6
通讯作者：
Mitzi, David B.
中科院分区：
文献类型：
--
作者：
Du, Ke-zhao;Meng, Weiwei;Mitzi, David B.
双钙钛矿家族，A（2）M（I）M（III）X（6），是克服当前光伏（PV）杰出产品CH 3 NH3 PbI 3所面临的铅毒性问题的有希望的途径。考虑到大多数已知的双钙钛矿内通常较大的间接带隙，带隙工程提供了一种重要的方法，用于在该系列内实现出色的PV性能。使用Cs2 AgBiBr 6作为主机，通过合金化的In-III/Sb-III的带隙工程已被证明在当前的工作。Cs2 Ag（Bi 1-xMx）Br-6（M=In，Sb）可容纳高达75%的In-III，带隙增加，以及高达37.5%的Sb-III，带隙减小;也就是说，能够实现约100%的Cs2 Ag（Bi 1-xMx）Br-6（M = In，Sb）。0.41 eV的带隙调制，通过引入的两种金属，与Cs2 Ag（Bi0.625Sb0.375）Br-6的1.86 eV的最小值。能带结构的计算表明，相反的带隙移动方向与Sb/In取代产生不同的原子配置这些原子。相关的光致发光和三金属系统的环境稳定性也进行了评估。
The double perovskite family, A(2)M(I)M(III)X(6), is a promising route to overcome the lead toxicity issue confronting the current photovoltaic (PV) standout, CH3NH3PbI3. Given the generally large indirect band gap within most known double perovskites, band-gap engineering provides an important approach for targeting outstanding PV performance within this family. Using Cs2AgBiBr6 as host, band-gap engineering through alloying of In-III/Sb-III has been demonstrated in the current work. Cs2Ag(Bi1-xMx)Br-6 (M=In, Sb) accommodates up to 75% In-III with increased band gap, and up to 37.5% Sb-III with reduced band gap; that is, enabling ca. 0.41 eV band gap modulation through introduction of the two metals, with smallest value of 1.86 eV for Cs2Ag(Bi0.625Sb0.375)Br-6. Band structure calculations indicate that opposite band gap shift directions associated with Sb/In substitution arise from different atomic configurations for these atoms. Associated photoluminescence and environmental stability of the three-metal systems are also assessed.