Yi Jun, Ge Xueying, Liu Exian, Cai Tong, Zhao Chujun, Wen Shuangchun, Sanabria Hugo, Chen Ou, Rao Apparao M, Gao Jianbo
Department of Physics and Astronomy, Clemson Nanomaterials Institute, Clemson University, Clemson, SC 29634, USA.
Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China.
Nanoscale Adv. 2020 Oct 1;2(10):4390-4394. doi: 10.1039/d0na00545b. Epub 2020 Jul 6.
We report a correlation between the structural phase transition of CsPbX (X=Cl, Br, I) nanocrystals (NCs) and their temperature dependent steady-state photoluminescence (PL) and time-resolved PL (TRPL). In constrast to CsPbBr and CsPbI NCs which exhibited a continuous blue shift in their bandgap with increasing temperature, the CsPbCl exhibited a blue shift until ~193 K, followed by a red shift until room temperature. We attribute this change from a blue to a red shift to a structural phase transtion in CsPbCl, which also manifested in the temperature dependent TRPL. Notably, the exciton recombination lifetimes showed a similar reverse trend due to the phase transition in CsPbCl, which has not been reported previously.
我们报道了CsPbX（X = Cl、Br、I）纳米晶体（NCs）的结构相变与其温度依赖性稳态光致发光（PL）和时间分辨光致发光（TRPL）之间的相关性。与CsPbBr和CsPbI纳米晶体在温度升高时其带隙呈现连续蓝移不同，CsPbCl在约193 K之前呈现蓝移，之后直到室温呈现红移。我们将这种从蓝移到红移的变化归因于CsPbCl中的结构相变，这也在温度依赖性TRPL中表现出来。值得注意的是，由于CsPbCl中的相变，激子复合寿命呈现出类似的相反趋势，这在之前尚未有报道。
