Identifying and Tuning Broadband Emissions in Multi-Layered Perovskites
Watcharaphol Paritmongkol a, Eric Powers a, Nabeel Dahod a, William Tisdale a
a Massachusetts Institute of Technology (MIT), Massachusetts Avenue, 77, Cambridge, United States
Poster, Watcharaphol Paritmongkol, 047
Publication date: 23rd April 2020

Halide perovskites have been shown to exhibit broadband or white-light emission. Two origins of broadband emission have been proposed: defect-associated emission and emission from self-trapped excitons. Herein, we show by photoluminescence spectroscopy that both kinds of broadband emission exist in multi-layered two-dimensional lead iodide perovskites. While defect-associated emission appeared in the visible region directly below the emission from free excitons, broadband emission due to self-trapped excitons were detected in the near-infrared region. Moreover, higher intensity self-trapped exciton emission was observed in thinner perovskites in agreement with stronger exciton-phonon couplings extracted from the analysis of temperature-dependent photoluminescence linewidth broadening. We also found that structural distortion played a major role in self-trapped exciton emission, and was largely dependent on A-site cations but less sensitive to organic spacers. This study illustrates the mechanisms behind broadband emission in multi-layered two-dimensional lead iodide perovskites and provides ways to tune the broadband emission for an application in single-source white-light phosphors.

© Fundació Scito
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