Plasmon-induced near-field and resonance energy transfer enhancement of photodegradation activity by Au wrapped CuS dual-chain

Self-assembled chain-like nanostructures utilizing localized surface plasmon resonance (LSPR) effect could enhance the local electromagnetic field for energy transfer, which provides huge structural advantages for some transmission-related applications such as photocatalysis. In this work, the dual-chain structure of Au chain wrapped CuS (denoted as Au Chain@CuS) was successfully synthesized by the one-step hydrothermal method. Namely, L-cysteine is used as the sulfur source and linking agent, and copper nitrate is the precursor of copper ions, forming the dual-chain driven by 15 nm uniform Au seeds. Transient absorption spectroscopy (TAS) and finite-difference-time-domain (FDTD) simulation exhibited the highly intensive electromagnetic field around the self-assembly chain, the raised formation and transfer rate of electron—hole pairs between the Au chain and surrounding CuS chain. Meanwhile, it shows an excellent photodegradation activity on dye rhodamine B (RhB). Within 1 h under simulated sunlight, the degradation rate reached 98.81% in Au Chain@CuS, which is 2.27 times higher compared to the bare CuS. The enhanced performance is mainly attributed to the near-field enhancement effect induced by LSPR, as well as the benefits of more effective resonance energy transfer (RET). This research comprehensively shows the electromagnetic field in LSPR metal chain is more intensive by order of magnitude relative to the isolated particles. Simultaneously the continuous CuS chain wrapped outside of the LSPR source effectively absorbs and utilizes the plasmonic energy, then promotes the formation of the photo-generated charge, thus increasing the photocatalytic performance. This founding of wrapped coupled-metal dual-chain provides a promising candidate for the highly efficient photocatalysts.