Regulating Hot-Carrier Dynamics via Indium Anchoring for Highly Stable CO2 Photoreduction on CsPbBr3 Nanocrystals

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Abstract
CsPbBr3 perovskite nanocrystals (PNCs) demonstrate exceptional photocatalytic potential in CO2 conversion through superior light harvesting and multi-exciton generation. However, their practical application is fundamentally hindered by structural instability that compromises carrier utilization. This study, using femtosecond transient absorption spectroscopy and temperature-dependent photoluminescence, reveals that dynamic coupling between hot carriers and lattice vibrations drives structural degradation via localized phonon excitations. To address this, we engineered indium (In)-anchored CsPbBr3 PNCs by targeted modification of surface Pb centers. The In-anchoring passivates defect-associated empty p-orbitals while prolonging the hot carrier lifetime by 98.86%. Furthermore, the introduced In atoms induce electronic localization, which suppresses phonon-driven lattice vibrations. As a result, charge separation and transport are dramatically enhanced, leading to a significant improvement in both CO2 reduction activity and stability. In contrast to CsPbBr3 PNCs, which completely deactivate within 20 h, In-anchored CsPbBr3 PNCs maintain stability over long-term operation for up to 60 h, while simultaneously exhibiting a 14.85-fold enhancement in CO yield. This study establishes a fundamental strategy for stabilizing perovskite photocatalysts by regulating hot carrier-lattice interactions, offering new insights into the design of high-performance CO2 reduction systems.

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