Unveiling the Potential of Halide Perovskites for Seasonally Adaptive CO₂ Photoreduction under Low Light Conditions

The viability of double perovskite Cs 2 AgBiBr 6 in low‐light environments is studied for CO 2 photoreduction. It is observed that light intensity significantly influences product formation with I 0.56 depending on the overall product formation rate. The photodetection measurement reveals that photocurrent as a function of incident power follows a power law ∝ I 0 α with α = 0.80, which is attributed to the carrier trapping at higher light power. Furthermore, power‐dependent transient absorption spectroscopy is studied and observed that at higher fluence, carrier scattering can be dominating. Interestingly, it is found that at higher power, hot carrier relaxation dynamics are altered, and electron‐phonon coupling is enhanced, resulting in a lower carrier concentration participating in the photocatalytic reaction, which can limit charge carrier extraction and CO 2 reduction. This study highlights the potential of perovskite semiconductors as promising candidates for photocatalytic reactions in low‐light conditions, broadening their applicability in real‐world scenarios.