Hot Polarons with Trapped Excitons and Octahedra‐Twist Phonons in CH3NH3PbBr3 Hybrid Perovskite Nanowires. Issue 1 (17th November 2019)

• Record Type: Journal Article
• Authors: Song, Feilong; Qian, Chenjiang; Wang, Yunuan; Zhang, Feng; Peng, Kai; Wu, Shiyao; Xie, Xin; Yang, Jingnan; Sun, Sibai; Yu, Yang; Dang, Jianchen; Xiao, Shan; Yang, Longlong; Jin, Kuijuan; Zhong, Haizheng; Xu, Xiulai
• Is Part Of: Laser & photonics reviews. Volume 14:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-17
• Subjects: exciton‐phonon interaction -- hot polarons -- hybrid perovskite -- trapped excitons; Lasers -- Periodicals; Photonics -- Periodicals; Lasers -- Périodiques; Photonique -- Périodiques; 621.36
• DOI: 10.1002/lpor.201900267
• Languages: English
• ISSNs: 1863-8880

Abstract

Abstract: Hybrid Perovskites have shown a great potential for applications in photovoltaics and light‐emitting devices with high efficiency. Interaction between defect‐induced trapped excitons and phonons plays an important role in understanding the emerging phenomena for such an excellent figure‐of‐merit. Here hot polarons with narrow linewidth in CH3 NH3 PbBr3 nanowires, which originate from the interaction between trapped excitons and octahedra‐twist phonons, are demonstrated. The observation of hot polarons in photoluminescence without gain methods indicates the large interaction strength between excitons and phonons. The multiple hot polarons are further confirmed by magneto‐optical spectra with a Zeeman splitting of the trapped excitons and a phonon energy increase with diamagnetic effect. Furthermore, the phonons participating in the interaction are demonstrated to be the octahedra‐twist vibrations which are transverse optical phonons, while the interaction between trapped excitons and longitudinal optical phonons is weak. The work demonstrates that trapped excitons in perovskites prefer to interact with transverse rather than longitudinal optical phonons. Since bulk materials usually interact with longitudinal optical phonons, this result provides a physical explanation of the high tolerance of defects in perovskites. Abstract : Due to narrow linewidth of localized excitons at low temperature, hot polarons are demonstrated in hybrid perovskite nanowires, which shows a large interaction between trappped excitons and TO phonons. The trapped excitons and free excitons show different preferences with interacting with different vibration modes, providing a physical explanation of the high tolerance of defects in hybrid perovskites.