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A simple method to fabricate edge-oriented MoS₂ films with sponge-like morphologies is demonstrated. They are directly fabricated through the reaction of sulfur vapor with anodically formed Mo oxide sponge-like films on flexible Mo substrates. The edge-oriented MoS₂ film delivers excellent hydrogen evolution reaction (HER) activity with enhanced kinetics and long-term cycling stability. The material also has superior energy-storage performance when working as a flexible, all-solid-state supercapacitor device.

Colloidal quantum dots (CQDs) are promising materials for novel light sources and solar energy conversion. However, trap states associated with the CQD surface can produce non-radiative charge recombination that significantly reduces device performance. Here a facile post-synthetic treatment of CdTe CQDs is demonstrated that uses chloride ions to achieve near-complete suppression of surface trapping, resulting in an increase of photoluminescence (PL) quantum yield (QY) from ca. 5% to up to 97.2 ± 2.5%. The effect of the treatment is characterised by absorption and PL spectroscopy, PL decay, scanning transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. This process also dramatically improves the air-stability of the CQDs: before treatment the PL is largely quenched after 1 hour of air-exposure, whilst the treated samples showed a PL QY of nearly 50% after more than 12 hours.

Photoluminescence with nearly 100% quantum yield is obtained from CdTe colloidal quantum dots by treating the surface with chloride ions. This process achieves near-complete passivation of the surface traps caused by dangling bonds, which otherwise cause significant non-radiative recombination, and also reduces the degradation of quantum yield with oxidation exposure.

A power conversion efficiency of 10.4% is demonstrated in planar CH₃NH₃PbBr₃ hybrid solar cells without hysteresis of the J–V curve, by way of controlled crystallization in the spin-coating process. The high efficiency is attributed to the formation of a dense CH₃NH₃PbBr₃ thin film by the introduction of HBr solution because the HBr increases the solubility of the CH₃NH₃PbBr₃ and forms a thinner CH₃NH₃PbBr₃ layer with full surface coverage.

An oxide semiconductor (perovskite-type Mn₂O₃) is reported which has a narrow and direct bandgap of 0.45 eV and a high Vickers hardness of 15 GPa. All the known materials with similar electronic band structures (e.g., InSb, PbTe, PbSe, PbS, and InAs) play crucial roles in the semiconductor industry. The perovskite-type Mn₂O₃ described is much stronger than the above semiconductors and may find useful applications in different semiconductor devices, e.g., in IR detectors.

Forming uniform metal oxide nanocoatings is a well-known challenge in the construction of core–shell type nanomaterials. Herein, by using buffer solution as a specific reaction medium, we demonstrate the possibility to grow thin nanoshells of metal oxides, typically Al₂O₃, on different kinds of core materials, forming a uniform surface-coating layer with thicknesses achieving one nanometer precision. The application of this methodology for the surface modification of LiCoO₂ shows that a thin nanoshell of Al₂O₃ can be readily tuned on the surface for an optimized battery performance.

Uniform surface coatings of Al₂O₃ with a thickness controllable at the one nanometer level were achieved by a solution-based synthesis route. Application of this coating methodology to LiCoO₂ showed that its battery performance as a cathode material can be optimized by means of systematic surface control.

A few-layered ternary Cu-In-Se compound is synthesized, the photoconductivity is measured, and 2D photovoltaic devices are fabricated. Few-layered CuIn₇Se₁₁ has a strong photoresponse and the potential to serve as the active medium in ultra-thin photovoltaic devices.

Nitrogen-rich quantum dots (N-dots) were serendipitously synthesized in methanol or aqueous solution at a reaction temperature as low as 50 °C. These N-dots have a small size (less than 10 nm) and contain a high percentage of the element nitrogen, and are thus a new member of quantum-dot family. These N-dots show unique and distinct photoluminescence properties with an increasing percentage of nitrogen compared to the neighboring carbon dots. The photoluminescence behavior was adjusted from blue to green simply through variation of the reaction temperature. Furthermore, the detailed mechanism of N-dot formation was also proposed with the trapped intermediate. These N-dots have also shown promising applications as fluorescent ink and biocompatible staining in C. elegans.

A new member of the family: Nitrogen-rich quantum dots were serendipitously synthesized at low temperature. These N-dots contain a high percentage of the element nitrogen and have unique photoluminescence properties. The photoluminescence behavior of N-dot solutions can be adjusted from blue to green simply by variation of reaction temperature. These N-dots show promising applications as fluorescent ink and biocompatible staining.

Whereas wide-bandgap metal oxides have been extensively studied for the photooxidation of water, their utilization for photoreduction is relatively limited. An important reason is the inability to achieve meaningful photovoltages with these materials. Using Cu₂O as a prototypical photocathode material, it is now shown that the photovoltage barrier can be readily broken by replacing the semiconductor/water interface with a semiconductor/semiconductor one. A thin ZnS layer (ca. 5 nm) was found to form high-quality interfaces with Cu₂O to increase the achievable photovoltage from 0.60 V to 0.72 V. Measurements under no net exchange current conditions confirmed that the change was induced by a thermodynamic shift of the flatband potentials rather than by kinetic factors. The strategy is compatible with efforts aimed at stabilizing the cathode that otherwise easily decomposes and with surface catalyst decorations for faster hydrogen evolution reactions. A combination of NiMo and CoMo dual-layer alloy catalysts was found to be effective in promoting hydrogen production under simulated solar radiation.

The photovoltage generated by Cu₂O in H₂O is readily increased by decorating the surface with a thin ZnS layer, which replaces the Cu₂O/H₂O interface and improves charge separation by Cu₂O. The strategy is compatible with stabilizing Cu₂O with TiO₂ and with various catalysts that promote the hydrogen evolution reaction and may enable the development of dual-absorber water splitting systems with the photocathode as the top layer.