甲基胺溴化铅晶体粉末的温度依赖光致发光

Temperature-dependent photoluminescence of CH3NH3PbBr3 crystal powder

  • 摘要: 采用稳态光致发光(PL)光谱技术,结合光谱学分析方法,对CH3NH3PbBr3(MAPbBr3)晶体粉末的功率密度和温度相关的光物理特性进行了研究。在405 nm连续激光激发下,PL发射峰位在560 nm,半高全宽为123 meV。光谱实验结果表明,通过对功率密度与PL强度进行拟合,其斜率为1.10,这很好地证明了单光子吸收的存在。在80~310 K温度范围内,MAPbBr3晶体粉末的荧光峰位表现出不同的温度依赖行为。随着温度的升高,激子-声子相互作用的增强,峰宽均匀展宽,积分强度逐渐减小。PL发射峰位在80~145 K出现蓝移。在150 K附近PL发射峰出现跳跃,而当温度超过150 K时,光谱的峰位几乎保持不变。这些温度相关的PL行为主要是由于在150 K左右发生了从正交相到四方相的结构相变。此外,从温度相关的PL实验数据拟合得到激子结合能约为49.8 meV和纵向光学声子能量约为60.4 meV。

     

    Abstract: In this work, the temperature-dependent behavior of CH3NH3PbBr3 (MAPbBr3) crystal powder is experimentally investigated using steady-state photoluminescence (PL) spectroscopy. Under 405 nm continuous-wave laser excitation, the fluorescence peak is at 560 nm with a full width at half maximum of 123 meV. There is a good linear increase in the luminescence intensity with increasing pump laser fluence, which indicates induced single-photon absorption. The MAPbBr3 crystal powder-induced PL exhibits different temperature-dependent behaviors at temperatures ranging from 80−310 K. As the temperature increases, the photon energy of the line width gets greater and the PL integral intensity gradually decreases because of the enhanced exciton phonon interaction. The peak of the PL spectrum shows a linear blue shift at 80−145 K. There is a very shallow slot around 150 K, while the peak position of the spectrum remains almost constant when the temperature exceeds 150 K. These temperature-dependent induced PL behaviors are mainly due to the contribution of phase transition and thermal expansion from orthogonal to tetragonal phases occurring at around 150 K. In addition, exciton binding energies of about 49.8 meV and longitudinal optical phonon energies of about 60.4 meV are derived from the temperature dependent PL experimental dataset.

     

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