无铅双钙钛矿Cs_(2)NaScX_(6)(X=Cl,Br,I)的第一性原理研究

First-principles Study on the Lead-free Double Perovskite Cs_(2)NaScX_(6)(X=Cl,Br,I)

钙钛矿材料由于具有结构稳定、易于获取、成本低廉和易于合成等优点,在发光二极管、激光器和太阳能电池等光电器件领域具有广阔的应用前景。目前,部分适合UV-LED应用的钙钛矿具有结构不稳定性。为了寻找结构稳定的钙钛矿,此项研究利用第一性原理对无铅双钙钛矿Cs_(2)NaScX_(6)(X=Cl,Br,I)的电子及光学性质进行了理论计算。计算结果表明:Cs_(2)NaScX_(6)(X=Cl,Br,I)为直接带隙半导体,带隙值分别为5.545 e V(Cl)、4.549 eV(Br)和3.408 eV(I),Cs_(2)NaScI_(6)在紫外光范围内具有较强的光吸收。本研究内容为无铅A_(2)B^(I)B^(III)X_(6)型双钙钛矿成为UV-LED的候选材料提供理论支持。

Perovskite materials have broad application prospects in light-emitting diodes,lasers,solar cells and other optoelectronic devices due to their stable structure,easy availability,low cost and simple synthesis.Currently,some perovskites suitable for UV-LED applications exhibit structural instability.The electronic and optical proper-ties of lead-free double perovskite Cs_(2)NaScX_(6)(X=Cl,Br,I)have been theoretically calculated by First-principles in order to identify a stable perovskite.The calculated results show that Cs_(2)NaScX_(6)(X=Cl,Br,I)is a direct bandgap semiconductor and the bandgap values are 5.545 eV(Cl),4.549 eV(Br)and 3.408 eV(I),respectively.Cs_(2)NaScI_(6) has strong light absorption in the ultraviolet range.This paper provides theoretical support for lead-free A_(2)B^(I)B^(III)X_(6) double perovskites as potential materials for UV-LED.