Ultralong Lifetime of Plasmon-Excited Electrons Realized in Nonepitaxial/Epitaxial Au@CdS/CsPbBr 3 Triple-Heteronanocrystals.

Combination of the strong light absorbing power of plasmonic metals with the superior charge carrier dynamics of halide perovskites is appealing for bio-inspired solar-energy conversion due to the potential to acquire long-lived plasmon-induced hot electrons. However, the direct coupling of these two materials, with Au/CsPbBr 3 heteronanocrystals (HNCs) as a prototype, results in severe suppression of plasmon resonances. Here, we show that interfacial engineering is a key knob for overcoming this impediment, based on creation of a CdS mediate layer between Au and CsPbBr 3 forming atomically organized Au-CdS and CdS-CsPbBr 3 interfaces by nonepitaxial/epitaxial combined strategy. Transient spectroscopy studies demonstrate that the resulting Au@CdS/CsPbBr 3 HNCs generate remarkably long-lived plasmon-induced charge carriers with lifetime up to nanosecond timescale, which is several orders of magnitude longer than those reported for colloidal plasmonic metal-semiconductor systems. Such long-lived carriers extracted from plasmonic antennas enable to drive CO 2 photoreduction with efficiency outperforming previously reported CsPbBr 3 -based photocatalysts. Our findings disclose a new paradigm for achieving much elongated time windows to harness the substantial energy of transient plasmons through realization of synergistic coupling of plasmonic metals and halide perovskites. This article is protected by copyright. All rights reserved.