Lead-Free Halide Double Perovskites via Heterovalent Substitution of Noble Metals
Lead-Free Halide Double Perovskites via Heterovalent Substitution of Noble Metals
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DOI：
10.1021/acs.jpclett.6b00376
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发表时间：
2016-04-07
影响因子：
5.7
通讯作者：
Giustino, Feliciano
中科院分区：
文献类型：
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作者：
Volonakis, George;Filip, Marina R.;Giustino, Feliciano
铅基卤化物钙钛矿正在成为下一代光电子学最有前途的一类材料;然而，尽管铅卤化物钙钛矿太阳能电池取得了巨大的成功，但稳定性和毒性问题尚未得到解决。在这里，我们报告的计算设计和实验合成的一个新的家庭的无铅无机卤化物双钙钛矿铋或锑和贵金属的基础上。使用第一性原理计算，我们表明，这个迄今为止未知的钙钛矿家族具有非常有前途的光电性能，如在可见光范围内的可调带隙和低载流子有效质量。此外，我们成功地合成了双钙钛矿Cs2 BiAgCl 6，使用单晶X射线衍射进行结构细化，并通过光吸收和光致发光测量表征其光学性质。这种新的钙钛矿属于Fm（3）在barm空间群，并由BiCl 6和AgCl 6八面体交替在岩盐面心立方结构。从紫外-可见光和光致发光测量，我们得到的间接间隙为2.2 eV。
Lead-based halide perovskites are emerging as the most promising class of materials for next-generation optoelectronics; however, despite the enormous success of lead-halide perovskite solar cells, the issues of stability and toxicity are yet to be resolved. Here we report on the computational design and the experimental synthesis of a new family of Pb-free inorganic halide double perovskites based on bismuth or antimony and noble metals. Using first-principles calculations we show that this hitherto unknown family of perovskites exhibits very promising optoelectronic properties, such as tunable band gaps in the visible range and low carrier effective masses. Furthermore, we successfully synthesize the double perovskite Cs2BiAgCl6, perform structural refinement using single-crystal X-ray diffraction, and characterize its optical properties via optical absorption and photoluminescence measurements. This new perovskite belongs to the Fm (3) over barm space group and consists of BiCl6 and AgCl6 octahedra alternating in a rock-salt face-centered cubic structure. From UV-vis and photoluminescence measurements we obtain an indirect gap of 2.2 eV.