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A quasi-particle named plexciton emerges from the hybridization between plasmons and molecular excitons which exhibits characteristic spectral features, such as Fano resonance and Rabi splitting in extinction, scattering, and reflection spectroscopy. However, the understanding of the fluorescence properties in plexcitonic hybrids remains unclear, especially for nonlinear upconverted emissions. In this Letter, we prepared three-component plexcitonic hybrids with two cyanine dyes (Cy3 and Cy5) coupled to Ag nanostructured films and investigated their enhanced nonlinear radiation, including two-photon luminescence (TPL), second-harmonic generation (SHG), and surface-enhanced Raman scattering (SERS). The plexcitonic hybrids showed a splitting extinction spectrum with five peaks induced by the hybrid of the monomer and dimer excitons in the two cyanine dyes with surface plasmon resonance of the Ag films. Under the laser excitation at 1260 nm, the (Cy3–Cy5)/Ag hybrid had a 6.3-fold enhancement of TPL and a 5.1-fold enhancement of SHG compared to a two-component hybrid of Cy5/Ag. Our experimental results provide valuable insights for designing and manufacturing multicomponent plexcitonic devices with highly efficient nonlinear radiation. The plexcitonic hybrids, characterized by their featured extinction properties and largely enhanced upconverted emission, have great promise for applications in nonlinear optics, quantum information processing, biomedical sensing, and photochemistry. [ABSTRACT FROM AUTHOR]

Metal core@semiconductor shell hybrids are regarded as promising candidates for plasmon-enhanced photocatalysis, but it remains a challenge to build semiconductor junctions on the shell region for further improved photocatalysis. Herein, Au core@dual-semiconductor coshell hybrids, whose shell was made by two different metal sulfides, were prepared by a one-pot direct growth method based on Au nanorods for highly improved photocatalysis for the first time. By inducing two different metal ions at the step of shell growth in a surfactant-assisted hydrothermal reaction, three types of Au@dual-semiconductor hybrids were prepared. In these hybrids, Au and two semiconductors intimately contact with each other, and three types of semiconductor heterojunctions including type I (ZnS–CdS), type II (Cu2–xS–Bi2S3), and Z-scheme (Bi2S3–CdS) are grown on Au nanorods. The as-prepared Au@dual-semiconductor hybrids show excellent photocatalytic activity on degrading rhodamine B under light irradiation, which is much higher than that of Au@single-semiconductor, semiconductor junctions, and Au@semiconductor@semiconductor hybrids with a double-layer shell. The enhanced mechanism can be ascribed to the accelerated carrier transfer and separation driven by the internal electric fields (IEFs) between semiconductors. Meanwhile, the plasmon-induced hot electron injection from Au to semiconductors can be promoted due to the cooperation of the Schottky junction or ohmic contact at metal–semiconductor interfaces and IEFs at semiconductor–semiconductor interfaces, which further promote the photocatalysis. [ABSTRACT FROM AUTHOR]

Favorable growth of asymmetric hetero‐nanostructures consisting of plasmonic metals and semiconductors or topological nanomaterials is highly desired because the performance of nonlinear optical antennas is closely related to their composition and morphology symmetry. In this work, two methods are proposed to overgrow PtSe2, a semiconductor or topological semimetal material, onto Au nanorods (AuNRs) to form Au/AuPt/PtSe2 and Au/AgPtSe2 heterorods via wet chemical technique. Both Au/AuPt/PtSe2 and Au/AgPtSe2 heterorods show asymmetric morphologies: the Au/AuPt/PtSe2 heterorods show a partially hollow morphology with an etched AuNR coated by AuPt and PtSe2 shells; the Au/AgPtSe2 heterorods prepared by Ag‐mediated overgrowth method have a toothbrush shape with AgPtSe2 attached on the side surface near one end of AuNRs. The two asymmetric heterorods show significantly enhanced nonlinear radiations of second harmonic generation with the excitation laser wavelength tuning from 1220 to 1315 nm, and a maximal nonlinear enhancement factor of 16 is achieved, which is attributed to the interaction of gold core with platinum selenide shell and the broken symmetry of heterostructures. The findings provide a strategy to prepare metal‐topological heterostructures as optical antennas with optimized performance in the application of nonlinear photonic nanodevices. [ABSTRACT FROM AUTHOR]

A three‐plasmon hybrid, in which core–shell Au@Cu2−xS hybrids are bonded with ultrathin Ti3C2Tx MXene, is prepared for high‐efficiency photothermal conversion and membrane‐based solar water evaporation for the first time. The MXene/Au nanorod@Cu2−xS hybrids display excellent photothermal conversion efficiency under irradiation of an 808 laser, causing by the three‐plasmon‐induced synergistic plasmonic absorption and heating effects as well as the multichannel charge transfer between the components. Then, Au nanosphere@Cu2−xS and Au nanorod@Cu2−xS hybrids are mixed and combined with MXene to serve as the membrane material, which shows excellent light absorption ranging from ultraviolet to near‐infrared region. By transferring the membrane materials on a hydrophilic cotton piece, the as‐prepared photothermal membrane displays a high evaporation rate of 2.023 kg m−2 h−1 and light‐to‐heat conversion efficiency of 96.1% under 1‐sun irradiation due to the synergistic photothermal conversion and over 96% of solar light absorption efficiency. Furthermore, a home‐made solar evaporation device enabling automatic inflow of untreated water and outflow of evaporated water is designed based on the principles of liquid pressure and connectors. The seawater desalination and sewage treatment experiments performed on the device and membrane indicate the great potential in solar‐light‐driven water purification and drinkable water generation. [ABSTRACT FROM AUTHOR]