Insights to Carrier-Phonon Interactions in Lead Halide Perovskites via Multi-Pulse Manipulation

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 19; no. 40; p. e2301831
• Main Authors: Feng, Minjun, Ye, Senyun, Lim, Jia Wei Melvin, Guo, Yuanyuan, Cai, Rui, Zhang, Qiannan, He, Huajun, Sum, Tze Chien
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.10.2023
• Subjects: Carrier density; Lead compounds; Metal halides; Nanotechnology; Perovskites; Phonons; Photovoltaic cells; Spectrum analysis; Thin films; carrier phonon interaction; hot carrier cooling; perovskite; pump push probe spectroscopy; phonon bottleneck
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202301831

A fundamental understanding of the hot-carrier dynamics in halide perovskites is crucial for unlocking their prospects for next generation photovoltaics. Presently, a coherent picture of the hot carrier cooling process remains patchy due to temporally overlapping contributions from many-body interactions, multi-bands, band gap renormalization, Burstein-Moss shift etc. Pump-push-probe (PPP) spectroscopy recently emerges as a powerful tool complementing the ubiquitous pump-probe (PP) spectroscopy in the study of hot-carrier dynamics. However, limited information from PPP on the initial excitation density and carrier temperature curtails its full potential. Herein, this work bridges this gap in PPP with a unified model that retrieves these essential hot carrier metrics like initial carrier density and carrier temperature under the push conditions, thus permitting direct comparison with traditional PP spectroscopy. These results are well-fitted by the phonon bottleneck model, from which the longitudinal optical phonon scattering time τ , for MAPbBr and MAPbI halide perovskite thin film samples are determined to be 240 ± 10 and 370 ± 10 fs, respectively.