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。

The toxicity and instability of lead halide perovskite seriously limit its commercial application in lighting, although it has high photoluminescence (PL) efficiency and adjustable emission. Here, lead-free bismuth (Bi) and antimony (Sb) codoped Cs2SnCl6 (BSCSC) microcrystals (MCs) are prepared successfully by a solvothermal method. The PL spectrum is composed of dual emission bands with the peak at 485 and 650 nm, of which relative intensity can be tunable through the change of Bi and Sb feeding contents, respectively. Because of the phonon–electron interaction, the PL intensity is enhanced as the temperature rises within the range of 80–260 K. Then, the nonradiative transition is intensified until 380 K, which results in decrease in PL intensity. Simultaneously, combining with time-resolved PL, it is concluded that the emission peak at 485 nm is attributed to the [BiSn+VCl] as the luminescent centers with the lifetime of hundreds of nanoseconds, and the emission peak at 650 nm is attributed to microsecond-timescale self-trapped excitons. The maximum values of relative sensitivity (SR) and absolute sensitivity (SA) values obtained are 3.82%K-1 and 5.11ns·K-1, which for the first time to our knowledge demonstrate that BSCSC MCs can be novel luminescent materials for developing better optical thermometry. White-light-emitting diodes (WLEDs) are constructed using BSCSC MCs only combined with an LED chip, the Commission Internationale de L’Eclairage color coordinates of which are (0.30, 0.37). It provides a novel scheme for the lighting field to realize WLEDs without adding additional commercial phosphors.

Extraordinary optical transmission (EOT) in subwavelength metal structures has been studied widely. Herein, we propose a strategy for tuning the EOT of the bullseye structure. Specifically, the bullseye structure was immersed in a nonlinear medium, and a controlling light was employed to change the refractive index of the medium. At different intensities and distributions of controlling light, the transmission property of signal light in the bullseye structure was simulated. The results show that a variable transmission spectrum in the bullseye structure can be realized. Moreover, the position of the central transmission peak shifts linearly with the increasing intensity of controlling light.