Unveiling the Ultrafast Electron Transfer Dynamics in Epitaxial Dodecahedron CsPbBr3/Au Heterostructure

Femtosecond transient absorption spectroscopy has been utilized to understand the charge transfer dynamics of CsPbBr₃/Au heterostructure. We find that distinct fast electron transfer in the CsPbBr₃/Au heterostructure, which is mainly ascribed to the strong epitaxial growth and strong electronic coupling between CsPbBr₃ and Au systems.

Abstract

Epitaxial perovskite heterostructures consisting noble metal nanoparticles have been received immense interest in hot carrier photovoltaic devices and photocatalysis. The major understanding of carrier extraction across the interface of perovskite heterostructure have shown exciting interest for next generation device applications. In the present study, dodecahedron CsPbBr₃/Au heterostructure was synthesized via hot injection method. From HR-TEM images, we observed direct epitaxial growth between (110) plane of CsPbBr₃ and (111) plane of Au nanoparticle (NPs), which was further supported by steady-state and time-resolved photoluminescence studies. Further, femtosecond transient absorption spectroscopy has been utilized to understand the charge transfer dynamics of synthesized samples. In CsPbBr₃/Au heterostructure, faster recovery has been noticed than that of pristine CsPbBr_3, which clearly suggests transfer of electrons from the conduction band of CsPbBr₃ to Au NPs. The distinct fast electron transfer in the CsPbBr₃/Au heterostructure can be mainly ascribed to the epitaxial growth and strong electronic coupling between CsPbBr₃ and Au NPs. The reduced bleach intensity, faster bleach growth and recovery kinetics strongly suggest efficient electron transfer from CsPbBr₃ NCs to Au NPs. These findings clearly establish that architecture of metal and perovskite heterostructures may pave way to develop suitable alternative for highly efficient photovoltaic devices and photocatalysis applications.

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