Carrier-Phonon Coupling Induced Carrier Localization in All-Inorganic Mixed-Halide Perovskite Micro-hemispheres

Bo-Ting Yang^1*, Li-Jyuan Lin¹, Chun-Sheng Wu¹, Hsu-Cheng Hsu¹

¹Department of Photonics, National Cheng Kung University, Tainan, Taiwan

* Presenter:Bo-Ting Yang, email:botingy@gmail.com

All-inorganic mixed-halide perovskites have attracted massive attention because of their stability and the application in optoelectronic device. However, the dynamics of carrier-transport and mechanism of recombination in all-inorganic mixed-halide perovskites have not been completely discussed. Here, we present carrier-phonon coupling induced carrier localization effect in crystalline lattice of CsPbBr_xCl_3-x micro-hemispheres perovskite (MHSP) measured at room temperature. The CsPbBr_xCl_3-x MHSP was obtained through vapor-anion-exchange reactions. After modifying the reaction temperature of anion-exchange reaction, we can control the composition of halides in our material. By measuring time-resolved photoluminescence (TRPL) and spectral-dependent TRPL, we found that the replacement of the heavier Br^- to the lighter Cl^- in CsPbBr₃ could enhance the carrier-phonon coupling strength, leading to the formation of the polaron in perovskite. The polaron formation is mainly responsible for prolonging the PL lifetime. This work offers the key for designing high-performance optoelectronic device.

Keywords: all-inorganic perovskite, carrier-phonon coupling, carrier localization, polaron