Improvement in hot carrier dynamics of all-inorganic halide perovskite CsPbI3 on doping Cu

Abstract

Hot carrier extraction is crucial for efficient solar energy harvesting, and lead halide perovskite nanocrystals (NCs) are potential candidates for photovoltaic and light-emitting applications. Therefore, swift extraction of hot carriers is an immediate requirement to improve the energy conversion efficiency, which need longer thermalization time. To address this issue, we synthesized nominally Cu-doped CsPbI3 NCs with enhanced structural and optical characteristics compared to undoped CsPbI3 NCs. We investigated the hot carrier dynamics in both the NCs at different fluences using ultrafast transient absorption spectroscopy. Interestingly, we observed very fast thermalization at higher fluences that indicated breaking of the phonon bottleneck. On the contrary, doped NCs preserved the effects and decayed over a longer period of time possibly due to increase in size and introduction of shallow trap states of Cu 3d and Cu 4s electrons in the conduction band, as computed using density functional theory. Notably, as the carrier–carrier interaction increased, we observed a dominating bandgap renormalization in the doped system compared to the undoped system. Overall, our studies improve the understanding of Cu doping in enhancing the hot carrier dynamics in perovskites and open possibilities for further investigation in the quantum phenomenon of these materials.

Unveiling Electron Dose-Induced Phase Decomposition and Energy Kinetics in Cu-Doped CsPbI3 Nanocrystals

“…The remarkable luminescent properties of lead halide perovskites (LHPs), coupled with efficient charge transport, high light absorption coefficient, tunable optical emission, and affordable synthesis costs, have catapulted them to the forefront of scientific research. − They are generally found in the form ABX 3 with large monovalent cations (MA + , FA + , Cs + ) and smaller divalent metal cations (Pb 2+ , Sn 2+ , etc.) occupying the A and B sites, respectively, while halide ions (Cl – , Br – , I – ) , cover the X sites.…”

Anomalous excitonic shift under near-resonant excitation in Cu-doped CsPbI3

“…Recently, many groups have addressed this issue by doping engineering with different transition metals including Mn, Cu, Co, etc. at the B site [6,7]. Here, we have chosen CsPbI3 because the excitonic position appears ~590-600 nm and metal (Cu) doping blueshifted the band which is suitable for our detector window (440 nm to 780 nm) as compared with confined CsPbBr3 (~505 nm).…”