1. Improvement of optical properties of lead-free double perovskite Cs2AgInCl6 nanocrystals through Bi ion alloying.
- Author
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Wang, Song, Xie, Ying, Zhao, Min, Sun, Jianhui, Wu, Wenzhi, Liu, Zihao, Sun, Huiyue, Lu, Luanhong, Shi, Keying, Qi, Lihong, and Pan, Kai
- Subjects
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ELECTRON-phonon interactions , *DENSITY functional theory , *BINDING energy , *OPTICAL properties , *NANOCRYSTALS - Abstract
Lead-free double perovskite nanocrystals (NCs) have garnered significant attention due to their non-toxicity and excellent stability, offering vast potential applications in the field of optoelectronics. They are considered promising substitutes for lead-based perovskite NCs. Herein, we successfully synthesized monodisperse, uniformly sized, cubic-shaped Cs 2 AgIn 1-x Bi x Cl 6 (0 ≤ x ≤ 1) NCs via a simple hot injection approach. The Cs 2 AgInCl 6 NCs exhibit a lower photoluminescence quantum yield (PLQY) of 3.9 % due to the presence of parity-forbidden transitions. However, with the introduction of Bi3+ alloying, the parity-forbidden transitions are broken, transforming into direct transitions allowed by parity. This transformation leads to efficient bright yellow emission, with the highest PLQY reaching up to 31.6 % (Cs 2 AgIn 0.90 Bi 0.10 Cl 6 NCs). Adjusting the Bi3+ alloying concentration allows tuning the NCs band gap from 3.62 eV to 2.88 eV, and the exciton lifetime can be extended from 5.99 ns to 24.88 ns. Temperature-dependent photoluminescence spectra and density functional theory calculations indicate that Bi3+ alloying increases the exciton binding energy, weakens the electron-phonon coupling, and breaks parity-forbidden transitions. Moreover, Cs 2 AgIn 0.90 Bi 0.10 Cl 6 NCs display outstanding stability under ambient conditions, laying a solid foundation for their applications in optoelectronics. The results of this study open a new pathway to enhance the optical performance of lead-free double perovskite nanomaterials. • Monodisperse Bi3+ alloyed Cs 2 AgInCl 6 nanocrystals were prepared. • Bi3+ alloyed Cs 2 AgInCl 6 nanocrystals show a improved PLQY of 31.6 %. • Bi3+ alloyed Cs 2 AgInCl 6 nanocrystals demonstrate a remarkable stability. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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