Hierarchical two-tier vibrational bath governing self-trapped exciton emission in the vacancy-ordered halide perovskite (NH4)2SnCl6

Chúng tôi vui mừng thông báo rằng TS. Mẫn Minh Tân và các đồng nghiệp đã xuất bản công trình có tựa đề "Hierarchical two-tier vibrational bath governing self-trapped exciton emission in the vacancy-ordered halide perovskite (NH₄)₂SnCl₆” trên tạp chí Journal of Physics and Chemistry of Solids

Tóm tắt:

This work explores the interplay between electronic structure and lattice dynamics in the lead-free halide perovskite (NH₄)₂SnCl₆. Structural characterization confirms a cubic vacancy-ordered lattice composed of isolated SnCl₆ octahedra. Combining Raman spectroscopy with density functional theory calculations reveals a distinctive two-tier vibrational bath, consisting of a primary phonon environment from the Sn–Cl framework and a secondary bath associated with rotational and librational motions of the NH₄⁺ cations. Electronic structure analysis shows that photoexcited carriers are strongly localized on the octahedral units, resulting in pronounced electron–phonon coupling and the formation of self-trapped excitons (STEs). Radiative recombination at 454 nm originates from a manifold of self-trapped exciton (STE) states, whose stabilization and significant energy displacement are dictated by the synergistic interactions within the two-tier vibrational bath. These findings highlight the critical role of molecular cations in modulating exciton–phonon interactions and provide a microscopic framework for designing high-efficiency STE-based luminescent materials in vacancy-ordered halide perovskites.