Speaker
Description
Non-stoichiometric plasmonic semiconductors such as Cu2-xS have emerged as promising materials for energy conversion applications owing to their tunable band gaps, cost-effectiveness, and ability to harvest near infrared (NIR) energy. Integrating these plasmonic semiconductors with lead halide perovskites in heterostructures enables strong plasmon-exciton coupling, resulting in enhanced light absorption and efficient interfacial charge transfer. This work presents synthesis and investigation of the spectroscopic behavior of non-stoichiometric Cu2-xS, CsPbBr3 nanocrystals (NCs) and their heterostructure. Femtosecond transient absorption (TA) measurements are performed at two different excitations (400 and 800 nm) to develop a fundamental understanding of the hot carrier dynamics and their extraction in the heterostructure system. The TA results confirm plasmon-induced hot-hole transfer from Cu2-xS to the valence band of CsPbBr3 at both excitations, while 400 nm excitation additionally promotes hot-electron transfer from CsPbBr3 to Cu2-xS conduction band, leading to efficient charge separation and retarded exciton recombination. The efficient charge separation results in enhanced photocurrent response for the heterostructure. These synergistic charge transfer processes establish the Cu2-xS-CsPbBr3 heterosystem as a strong candidate for high performance optoelectronic devices.