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Modulating the Carrier Relaxation Dynamics in Heterovalently (Bi 3+ ) Doped CsPbBr 3 Nanocrystals.

Kritiman MarjitGoutam GhoshRaju K BiswasSrijon GhoshSwapan K PatiAmitava Patra
Published in: The journal of physical chemistry letters (2022)
Manipulation of intrinsic carrier relaxation is crucial for designing efficient lead halide perovskite nanocrystal (NC) based optoelectronic devices. The influence of heterovalent Bi 3+ doping on the ultrafast carrier dynamics and hot carrier (HC) cooling relaxation of CsPbBr 3 NCs has been studied using femtosecond transient absorption spectroscopy and first-principles calculations. The initial HC temperature and LO phonon decay time point to a faster HC relaxation rate in the Bi 3+ -doped CsPbBr 3 NCs. The first-principles calculations disclose the acceleration of carrier relaxation in Bi 3+ -doped CsPbBr 3 NCs due to the appearance of localized bands (antitrap states) within the conduction band. The higher Born effective charges ( Z *) and higher soft energetic optical phonon density of states cause higher electron-phonon scattering rates in the Bi-doped CsPbBr 3 system, which is responsible for the faster HC cooling rate in doped systems.
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