Tuning the Competitive Recombination of Free Carriers and Bound Excitons in Perovskite CH3NH3PbBr3 Single Crystal
Tuning the Competitive Recombination of Free Carriers and Bound Excitons in Perovskite CH3NH3PbBr3 Single Crystal
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调节钙钛矿 CH3NH3PbBr3 单晶中自由载流子和束缚激子的竞争复合
DOI：
10.1021/acs.jpcc.7b00735
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发表时间：
2017
影响因子：
3.7
通讯作者：
Wang Qu Quan
中科院分区：
文献类型：
--
作者：
Qiu Yun Hang;Nan Fan;Wang Qiang;Liu Xiao Dan;Ding Si Jing;Hao Zhong Hua;Zhou Li;Wang Qu Quan
钙钛矿型CH3NH3PbBr3晶体的激发产生长寿命载流子，这些载流子通过自由电子和空穴或局域激子辐射复合。在这里，我们通过调节双光子激发波长来研究自由载流子和束缚激子的竞争复合。在远离共振的激发下，由于激子结合能与室温下的热能相当，CH3NH3PbBr3钙钛矿单晶表现出自由载流子上转换发射。在近共振激发下(1.97 eV<；hνexc<；2.16 eV)，首次报道了声子能量为∼186 meV的反斯托克斯过程。此外，当反斯托克斯跃迁与带以下的局域激子能级共振时，观察到束缚激子复合产生的高效率上转换发光。研究发现，激发态复合动力学随激发波长的变化而变化，这对发展高性能光学器件具有重要意义。
Excitation of perovskite CH3NH3PbBr3 crystal generates long-lived carriers, which radiatively recombine via free electrons and holes or localized excitons. Here, we investigate the competitive recombination of free carriers and bound excitons by tuning two-photon excitation wavelength. At excitation far from resonance, the CH3NH3PbBr3 perovskite single crystal shows the free carrier up-conversion emission because the exciton binding energy is comparable with the thermal energy at room temperature. At excitation near resonance (1.97 eV < hνexc < 2.16 eV), the anti-Stokes process with a consistent phonon energy of ∼186 meV is reported for the first time. Furthermore, when the anti-Stokes transition is resonant with localized exciton level below the band, highly efficient up-converted luminescence from the bound exciton recombination is observed. The finding that the excited state recombination kinetics vary versus excitation wavelength, in the present work, is helpful for developing the high-performance opt...