The origins of dual-peak emission and anomalous exciton decay in 2D Sn-based perovskites.
J Chem Phys
; 161(1)2024 Jul 07.
Article
em En
| MEDLINE
| ID: mdl-38953446
ABSTRACT
Two-dimensional (2D) Sn-based perovskites exhibit significant potential in diverse optoelectronic applications, such as on-chip lasers and photodetectors. Yet, the underlying mechanism behind the frequently observed dual-peak emission in 2D Sn-based perovskites remains a subject of intense debate, and there is a lack of research on the carrier dynamics in these materials. In this study, we investigate these issues in a representative 2D Sn-based perovskite, namely, PEA2SnI4, through temperature-, excitation intensity-, angle-, and time-dependent photoluminescence studies. The results indicate that the high- and low-energy peaks originate from in-face and out-of-face dipole transitions, respectively. In addition, we observe an anomalous increase in the non-radiative recombination rate as temperature decreases. After ruling out enhanced electron-phonon coupling and Auger recombination as potential causes of the anomalous carrier dynamics, we propose that the significantly increased exciton binding energy (Eb) plays a decisive role. The increased Eb arises from enhanced electronic localization, a consequence of weakened lattice distortion at low temperatures, as confirmed by first-principles calculations and temperature-dependent x-ray diffraction measurements. These findings offer valuable insights into the electronic processes in the unique 2D Sn-based perovskites.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2024
Tipo de documento:
Article