Electron Transfer\nDynamics from CsPbBr₃ Nanocrystals to Au₁₄₄ Clusters

Abstract

Lead halide perovskite\nnanocrystals have received significant attention\nas an absorber material for designing efficient optoelectronic devices.\nThe fundamental understanding of the hot carrier (HC) dynamics as\nwell as its extraction in hybrid systems is essential to further boost\nthe performance of solar cells. Herein, we have explored the electron\ntransfer dynamics in the CsPbBr₃-Au₁₄₄ cluster\nhybrid using ultrafast transient absorption spectroscopy. Our analysis\nreveals faster HC cooling time (from 515 to 334 fs) and a significant\ndrop in HC temperature from 1055 to 860 K in hybrid, suggesting the\nhot electron transfer from CsPbBr₃ nanocrystals to the\nAu nanoclusters (NCs). Eventually, we observe a much faster hot electron\ntransfer compared to the band-edge electron transfer, and 45% hot-electron\ntransfer efficiency was achieved at 0.64 eV, above band-edge photoexcitation.\nFurthermore, the significant enhancement of the photocurrent to the\ndark current ratio in this hybrid system confirms the charge separation\nvia the electron transfer from CsPbBr₃ nanocrystals to\nAu₁₄₄ NCs. These findings on HC dynamics could be beneficial\nfor optoelectronic devices.