the emerging global energy crisis. [1] To boost the hydrogen production efficiency, the rational design and fabrication of semiconductor photoelectrodes with broad light absorption, adequate exciton generation, efficient charge separation/transfer, and long-term stability are highly desired. [2] Recently, semiconductors quantum dots (QDs) have demonstrated huge potential as light sensitizers in photoanodes for high efficiency solar-driven PEC application due to their size/shape/composition-tunable optical properties that features considerable overlap with solar spectrum. [3] However, the state-of-the-art QDs used in current PEC systems still suffer from major limitations including highly toxic heavy metal elements (Pb, Cd etc.), insufficient charge separation/transfer, and low photo-stability. [1b,4] Developing eco-friendly core/shell structured QDs is a promising strategy to address these issues, while a proper selection of core and shell materials is necessary to obtain core/shell QDs with tailored band structure, optimized optical properties/ charge dynamics, and enhanced photo/chemical stability for high performance and stable solar-to-hydrogen conversion.Among various semiconductor QDs, heavy metal-free InP QDs have recently attracted great attention due to their large absorption coefficient, narrow band gap (≈1.34 eV in bulk), and wide wavelength tunability. [5] Nevertheless, bare InP QDs can exhibit abundant surface defect states, resulting in severe non-radiative recombination for largely reduced quantum yield (QY, usually <5%) and photo/chemical stability. [6] Generally, inorganic shell (such as ZnS and ZnSe) were coated on InP core QDs to form type I band alignment with improved radiative emission and photo/chemical stability. [7] Considering the stress-induced defects at the core/shell interface, the ZnSe shell with a lower lattice mismatch (3.4%) as compared to ZnS (7.6%) is more appropriate to coat on InP core for optimized optical characteristics. [8] In 2019, Jang et al. synthesized InP/ZnSe/ZnS QDs to fabricate a red QDs-light-emitting diode (QLED) with an external quantum efficiency of 21.4%, which is considered as a milestone for the display application based on environmentally friendly QDs, demonstrating the huge potential of InP-based core/shell QDs as building blocks in optoelectronic devices. [9] However, to date, most of the investigations regarding InP-based core-shell QDs are mainly focused on enhancing As emerging eco-friendly alternatives to traditional Cd/Pb-based quantum dots (QDs), InP/ZnSe(S) core/shell QDs have demonstrated huge potential in light-emitting technologies. So far, these QDs have been rarely employed in solar energy conversion applications due to their type-I band structure offering limited photo-induced charge carrier separation and transfer. Here, a controllable Cu shell doping approach is reported to engineer the optoelectronic properties of InP/ZnSe core/shell QDs and realize high performance and stable solar-driven photoelectrochemical (PEC) hydrogen evol...

Molybdenum disulphide (MoS2), a layered quasi-two dimensional (2D) chalcogenide material, is a subject of intense research because of its electronic, optical, mechanical and physicochemical properties. Since the monolayer MoS2 is a direct-gap seminconductor, it is widely used in the field of light-emitting area. However, its photoluminescence (PL) efficiency is very low due to excessive doping in monolayer MoS2 and rich non-radiative centers. In this letter, we reportits synthesis using the gold nanoparticles which have a resonance absorption peak around 514 nm. The gold nanoparticles are dispersed on the surface of the MoS2 samples by means of spin-coating. Then, we measure the photoluminescence (PL) of the monolayer, bilayer and multilayer samples before and after the spin-coating, and find a great enhancement in the PL intensity of the monolayer sample. Also the PL intensities of bi-layer and multiple layer MoS2 samples are slightly enhanced. Our work shows that gold nanoparticles may impose an obvious p-doping effect to the monolayer and bi-layer MoS2 samples to enhance the PL, and a surface plasmon polariton effect of the gold nanoparticles is also a positive factor for the enhancement.