Xue Chen, Huang Hengming, Nishihara Sadafumi, Biju Vasudevanpillai, Ren Xiao-Ming, Nakamura Takayoshi
Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan.
Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan.
J Phys Chem Lett. 2022 Aug 18;13(32):7405-7412. doi: 10.1021/acs.jpclett.2c01978. Epub 2022 Aug 4.
Semiconductors that emit intrinsic white light are considered next-generation lighting sources. Herein, the broadband emission of one-dimensional (1D) lead halide perovskites, TMAPbBrI ( = 0, 1, 1.5, 2, 3; TMA = tetramethylammonium), is systematically investigated. Lattice distortion causes the conversion of dark excitons to bright self-trapped excitons. Owing to its strongly localized exciton recombination and high absorption probability, TMAPbBr is the most viable in this family. A delocalized hole increases the nonradiative recombination rate of excitons in TMAPbBrI alloys. In 1D TMAPbBrI perovskites, the vibration mode of the Pb-X bond stretching of the PbX octahedra contributes more to the effect on exciton-phonon coupling than the mode of the X-Pb-X angle bending. Pb-X bond stretching and spontaneous polarization can tune exciton binding energy. This systematic study of excitonic behavior in 1D compounds relates the nature of ground states to the unknown excited states and provides the rational design of materials with stable and efficient broadband emission.
发射本征白光的半导体被视为下一代照明光源。在此，对一维（1D）卤化铅钙钛矿TMAPbBrI（ = 0、1、1.5、2、3；TMA = 四甲基铵）的宽带发射进行了系统研究。晶格畸变导致暗激子向明亮的自陷激子转变。由于其激子复合强烈局域化且吸收概率高，TMAPbBr是该家族中最具可行性的。离域空穴会增加TMAPbBrI合金中激子的非辐射复合率。在一维TMAPbBrI钙钛矿中，PbX八面体的Pb - X键拉伸振动模式对激子 - 声子耦合的影响比X - Pb - X角弯曲模式更大。Pb - X键拉伸和自发极化可调节激子结合能。对一维化合物中激子行为的这一系统研究将基态性质与未知的激发态联系起来，并为具有稳定高效宽带发射的材料提供了合理设计。
