Charge-Phonon Coupling in Tin Halide Perovskites
Lorenzo Gatto, Isabella Poli, Daniele Meggiolaro, Federico Grandi, Giulia Folpini, Antonella Treglia, Eugenio Cinquanta, Annamaria Petrozza, Filippo De Angelis, C. Vozzi
Abstract
High Resolution Image Download MS PowerPoint Slide Tin halide perovskites are promising materials to replace lead-based materials for perovskite optoelectronics, yet their performance is limited by their high self-p-doping. To quantify the impact of p-doping on carrier dynamics, we combine terahertz spectroscopy and density functional theory calculations to investigate the coupling of charge carriers to the lattice in prototypical tin-based perovskites. Doping is shown to influence the charge-phonon interactions significantly. We identify the formation of polarons at doping densities below 10 18 cm –3, while a Drude-like response is found for photogenerated carriers at higher charge density, confirming that for highly p-doped systems, the terahertz response is dominated by quasi-free charge carriers. Our study suggests that charge-phonon coupling could serve as a proxy for the self-p-doping level, offering additional insights into fundamental charge-transport properties of tin halide perovskites and their potential optimization for photovoltaic applications.