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The photocatalytic performance of graphitic carbon nitride (g-C 3 N 4) heterostructures related to the charge carrier separation and transport efficiency is often governed by the interfaces. Herein, in-situ growth of W 18 O 49 nanobelts is attained on amorphous and crystalline g-C 3 N 4 nanosheets to study the effects of the interfaces on photocatalytic oxidation activities. The horizontal growth of W 18 O 49 on g-C 3 N 4 nanosheets is the key in formation of two dimensional (2D)/2D W 18 O 49 /g-C 3 N 4 heterostructures. The growth of W 18 O 49 nanobelts on crystalline g-C 3 N 4 nanosheets shows well-developed interfaces (sample W 18 O 49 -CCN) in comparison with heterostructures constructed using amorphous g-C 3 N 4 base (sample W 18 O 49 -ACN). Characterizations on the structure, components, and properties of the samples demonstrate that these heterostructures reveal extended photo-absorption in visible to near infrared region, with sample W 18 O 49 -CCN showing much higher photogenerated charge carrier separation and transport efficiency. A H 2 O 2 evolution rate of 5550 µMg−1h−1 is observed for sample W 18 O 49 -CCN under full solar-spectrum illumination (and 398 µMg−1h−1 observed for pristine crystalline g-C 3 N 4), which is ∼ 2.4 times of that of sample W 18 O 49 -ACN prepared using amorphous g-C 3 N 4. In addition, a NO removal rate of 72.1% is observed for sample W 18 O 49 -CCN with a NO 2 selectivity of 6.2%. These results provide inspiration for construction of g-C 3 N 4 homojunctions for practical photo-redox reaction applications. [Display omitted] • The horizontal growth of W 18 O 49 nanobelts on g-C 3 N 4 nanosheets is the key to form layered heterostructures. • W 18 O 49 /crystalline g-C 3 N 4 heterostructures revealed well-developed interfaces compared with their amorphous counterparts. • A H 2 O 2 evolution rate of 5550 µMg−1h−1 is observed for the heterostructures prepared using crystalline g-C 3 N 4. • A NO removal rate of 72.1% is observed for the heterostructures prepared using crystalline g-C 3 N 4. [ABSTRACT FROM AUTHOR]

Abstract: Highly transparent silica–titania films with dense and mesoporous structures were prepared by the sol–gel process. The films were prepared by a single spin coating process using mixed silica–titania sols, followed by annealing at 180°C. The transmittances of both films were higher than 97% in the UV–visible-IR range. The refractive index of the dense film measured by ellipsometry was 1.87–1.59 in the range of 300–1100nm (1.63 at 500nm). The pencil hardness test showed that the hardnesses of the dense and porous films were over 9H and 3B, respectively. The cytotoxicity test (MTT assay) showed that both films had no poisonous effect on the living cells. From the surface composition analysis by X-ray photoelectron spectroscopy, SiO2 was found to exist on the film surface which could be responsible to the good biocompatibility of the film. [Copyright &y& Elsevier]

Effect of surface sulfurization on the solar conversion efficiency of Cu-Zn-Sn (CZT) alloy film, which was prepared by DC-magnetron sputtering with a single Cu-Zn-Sn target, followed by a H 2 S-sulfurization-after-H 2 Se-selenization (SAS) process to convert the alloy film to a Cu 2 ZnSn(S, Se) 4 (CZTSSe) absorber, was investigated. Compared with a conventional Cu 2 ZnSnSe 4 (CZTSe) solar cell selenized in H 2 Se, the conversion efficiency of CZTSSe one prepared in the SAS process was increased from 2.1% to 7.5% (increased by 257%). Conductive atomic force microscopy exhibited that the SAS process effectively reduced the leakage current near the grain boundary, while the external quantum efficiency measurement clearly demonstrated that the SAS process increased the energy bandgap by ~0.13 eV and significantly reduced the surface defects in the shorter wavelength region. Raman and temperature-dependent photoluminescence spectroscopies elucidated that the SAS process also led to secondary phases (e.g., SnS, ZnS and Cu 2 SnS 3 ) and structural defects (e.g., Zn Sn ), which are considered to be a key to achieve a highly efficient CZTSSe solar cell in the future. [ABSTRACT FROM AUTHOR]

Hierarchical bimetallic Ni-Co phosphides hollow spheres were encapsulated in P-doped reduced graphene oxide (PrGO) to provide superior electrochemistry performances. The hollow spheres with controlling Co/Ni ratios were obtained via a hydrothermal process and following phosphorization reaction using Ni-Co based glycerate microsphere as a self-sacrificing template. The hollow shell with vertical branches was formed via a morphology evolution of solid, yolk-shell to hollow. The hollow spheres were encapsulated in PrGO networks by a hydrothermal synthesis and phosphorization process to fabricate PrGO/Ni-Co phosphide composite (PrGO/NiCoP). Because of unique morphology and composition, the composite with a Ni/Co molar ratio of 1:1 exhibits enhanced supercapacitor and electrocatalysis properties. As a supercapacitor electrode, PrGO/NiCoP provides high discharge specific capacity, excellent rate performance and cycle stability. An asymmetric supercapacitor assembled with PrGO/NiCoP and activated carbon possesses an energy density of 49.7 Wh/Kg with power density of 0.366 kW/kg, which can successfully illuminate red-light light emitting diode. As an electrocatalyst, PrGO/NiCoP exhibits high hydrogen and oxygen evolution reaction activities in 1 M KOH electrolyte. PrGO/NiCoP electrolyzer shows excellent overall water splitting performance and durability, which required a cell voltage of 1.56 V to achieve a current density of 10 mA cm−2. NiCoP hollow microsphere/phosphorus-doped reduced graphene oxide composites have been successfully synthesized, which exhibits superior asymmetric supercapacitor and electrocatalytic overall water splitting performances. Image 1 [ABSTRACT FROM AUTHOR]

Non-metal doping not only optimizes the energy band structure of g-C 3 N 4 to improve the absorption of visible light, but also exacerbates the distortion of lowest and highest unoccupied molecular orbital plane, causing polarization, thereby improving photocatalytic activity. For the first time, S and P are co-introduced into g-C 3 N 4 network to enhance photocatalytic performance and create various tubular morphologies. The ratio of S to P is crucial to control the tubular morphology and property. In the photocatalytic process, the separation of electrons and holes causes by the polarization of the S and P elements and the synergy of the tubular morphology results in new migration paths for photogenerated electrons and holes. Using optimized preparation conditions, g-C 3 N 4 tubes co-doped with S and P (CNSP) reveal very high H 2 generation efficiency (163.27 μmol/h), which is two orders of magnitude higher compared to that of pure g-C 3 N 4 and apparent quantum yield is 18.93% at 420 nm. Fast degradation of Rhodamine B by using CNSP occurs within 5 min under visible light irradiation. Because of the reproducible process, the synthetic strategy provides a novel method for controlling the morphology of g-C 3 N 4 -based materials with super activity. Image 1 • g-C 3 N 4 nanotubes with controlled morphology were prepared via S and P Co-doped. • g-C 3 N 4 nanotubes revealed superior high H 2 generation efficiency. • Photogenerated electrons and holes migrate to the outer and inner tube walls. [ABSTRACT FROM AUTHOR]

Abstract In order to construct the molybdenum disulfide (MoS 2) hybrid nanostructure with enhanced conductivity and more active sites towards electrocatalytic hydrogen evolution reaction (HER), hierarchical P-doped MoS 2 nanopetals decorated N-doped hollow carbon spheres (N-C@P-MoS 2) core-shell structures were synthesized via calcination and hydrothermal methods. N-C@P-MoS 2 with optimized loadings exhibited favorable HER activities with low onset overpotential (117 mV), small Tafel slopes (68 mV/dec), and fine stability compared with pure MoS 2 nanosheets and all undoped samples. This is largely ascribed to the synergy of MoS 2 and carbon in the rational hierarchical structures, as well as the modified electronic structure with improved conductivity, increased active sites by virtue of N and P doping. Furthermore, P-doped MoS 2 nanosheets were encapsulated in carbon spheres (N-C/P-MoS 2 (inside)) by controlling the dropping rate of adding MoS 2 precursors. As the active sites were hampered, the N-C/P-MoS 2 (inside) revealed poor HER performance compared with the core-shell counterparts. The results demonstrate that the fabrication of hierarchical MoS 2 /carbon composites with the synergy of structural (morphology and content) and electronic (active sites and conductivity) effects induced by various nonmetal doping pave the way for enhanced electrocatalytic HER activities. Graphical abstract The P-doped MoS 2 nanopetals decorated hollow N-doped carbon spheres core-shell structures (N-C@P-MoS 2) were synthesized successfully via hydrothermal method. Due to the synergy of modified electronic effect and controllable structural effect, the N-C@P-MoS 2 exhibited desirable property in electrocatalytic hydrogen production, compared with other undoped and inside structures. Image 1 Highlights • The P-MoS 2 decorated on and in N-CS were synthesized by controllable hydrothermal and calcination method successfully. • N-C@P-MoS 2 with optimized loadings exhibits desirable HER activity by various nonmetal doping. • The enhanced performance is ascribed to the synergy of controllable structural effect and modified electronic effect. [ABSTRACT FROM AUTHOR]

Effects of alcohols on the growth and morphology of TiO 2 from two different self-organization methods, i.e., water-vapor hydrolysis and ultraslow water-diffusion hydrolysis, were investigated. In the first method, Ti alkoxide was hydrolyzed by water vapor to generate TiO 2 particles in a solution, which exhibited that the alcohols not only reduced the anatase crystal size, but also influenced the packing density of secondary particles and the subsequent sintering outcome, which are attributable to involvement of the alcohols in both self-organization and crystallization processes. In the other method based on the ultra-slow water-diffusion hydrolysis, ethanol led to very compact spherical secondary particles that resulted in a lower sintering temperature, while methanol caused the anisotropic growth of particles that produced two novel 1D structures, i.e., rectangle tubes and flower-like slabs due to incorporation of a structurally different alcohol in the sol-gel process. [ABSTRACT FROM AUTHOR]

Nowadays, large area CuIn x Ga 1− x Se 2 (CIGS) thin film solar cells still face difficulties and challenges of the uniformity of composition and structure. This study illustrates how Se concentration affects the crystal growth and the defect formation of CIGS from low cost electrodeposited stacked Cu/In/Cu/Ga/Cu layers selenized in the rapid thermal process. Various crystal growth modes were observed in the film selenized with different Se concentrations. It was found that the crystal growth was strongly dependent on the Se concentration in the early stage of selenization between 250 and 350 °C, which can lead to variations of film composition and structure including a phase separation of CuGaSe 2 from CuInSe 2 and formation of defect holes in a CIGS film at a higher selenization temperature. [ABSTRACT FROM AUTHOR]

Electrodeposition is a promising method to realize large-scale and low-cost CuIn x Ga 1− x Se 2 thin film solar cells. In this study, we investigate the out-of-plane compositional and structural variations of electrodeposited Cu/In/Cu/Ga/Cu stacked layers selenized at different temperatures in the rapid thermal process by employing cross-sectional scanning electron microscopy, grazing incidence X-ray diffraction, inductively coupled plasma atomic emission spectroscopy, confocal Raman spectroscopy, and Auger spectroscopy. A growth model has been suggested to describe the material structure and the chemical composition of the electrodeposited CIGS thin film during the selenization process on the basis of the experimental results. [ABSTRACT FROM AUTHOR]

In this study, we investigated the material growth and the local compositional homogeneity of CIGS thin films selenized from elemental Cu, In, Cu, Ga, and Cu stacked layers prepared by sequential electrodeposition, which is considered to be a promising production method for large-area thin film solar cells. It showed that the stacked layers first formed mixed metallic phases after a pre-heat treatment at 150 °C in vacuum. Several intermediate phases such as CuInSe 2 , CuIn rich Ga poor Se 2 , Cu 2 Se, InSe/In 2 Se 3 , CuGa 2 , and CuIn poor Ga rich formed in Se vapor at a lower temperature (e.g., <350 °C). Moreover, separation of the Ga-rich phase from the In-rich one was found in the film after selenization at 350 °C, which is due to relatively slow growth for the Ga-related grains that was buried by the In-rich phase growing faster in the out-of-plane orientation. All metallic phases converted to separate CuInSe 2 and CuGaSe 2 phases when selenized at 450 °C. Additional heat treatment at 550 °C in Ar improved the Ga distribution, which enhanced the light absorbance. [ABSTRACT FROM AUTHOR]

3D polymer/quantum dots (QDs) nanocomposite QD-lens is fabricated by stereolithography (SLA) 3D printer with in-situ UV curing system. Various UV-curable polymer precursors are mixed with QDs to investigate their printability and optical performance. 2D QD-thin film and 3D QD-lens are printed and attached to a blue InGaN chip to form a light-emitting diode (LED) device. An air gap between the 3D QD-lens and the chip provides more uniform light emission at different angles and better heat dissipation. Compared with conventional QD-on-chip LED, the 3D QD-lens LED operated at 20 mA has ∼100% enhancement of half-lifetime (T 50) in a standard reliability test. The LED T 50 can be further improved 75% by coating the QD-lens with hydrophobic parylene as a gas barrier layer against water and oxygen. By mixing both green- (G-) and red- (R-) QDs in the 3D QD-lens, a white light-emitting 3D QD-lens LED is demonstrated to possess a color gamut of ∼130% NTSC standard. [Display omitted] [ABSTRACT FROM AUTHOR]

A fabrication process of polycarbonate (PC) light guide plate (LGP) incorporating fluorescent quantum dots (QDs) is presented in this study. QD-PC composite pellets with dimension of 500 to 2500 μm were first prepared from a mixture of polyethylene-treated QDs and PC resin powder, followed by injection moulding to form a QD-LGP between 340 and 295 °C. The fabricated QD-LGPs demonstrated dual functions of light guiding and QD colour conversion, which is conventionally provided by a LGP covered with an additional QD diffuser film. By directly embedding QDs into a LGP, it was found that a rather low cadmium content around 41 ppm was sufficient to provide a uniform backlighting for a liquid-crystal display with a colour gamut of ~115% NTSC standard. Unlabelled Image • Quantum dots are incorporated into polycarbonate light guide plates as an alternative design of wide-gamut backlight. • The quantum-dots-based light guide plate is fabricated with an industrial injection moulding production line. • The consumption of quantum dots material is reduced to only 0.06 wt% where the cadmium content is lower than 50 ppm. • A double-edge lighting 3.4″ quantum-dots-based backlight with uniform planar lighting reaches ~115% of NTSC standard. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2) is one of the promising candidates for hydrogen evolution reaction (HER), it's HER properties can be extremely enhanced by the construction of nanostructure and the regulation of electronic structure. In this paper, hierarchical composites with MoS 2 and carbon nanotubes (CNTs) as the noble metal-free electrocatalysts for HER were fabricated through calcination and hydrothermal processes, in which the MoS 2 nanosheets with Ni atoms incorporation were vertically grown on the outsides of nitrogen (N)-doped CNTs. The constructed hierarchical structures provide large specific surface area of about 150 m2 g−1 and high structure stability. Importantly, the MoS 2 nanosheets with enlarged interlayer spacing possess ultrathin structure of about 4 nm in thickness. Owing to the incorporation of Ni atoms, abundant unsaturated S atoms are obtained in the basal plane, which leading to more active sites exposed during HER processes. Meanwhile, N-doped CNTs can act as the substrate for MoS 2 nanosheets growing and simultaneously improve the conductivity of catalyst. Based on the synergy of hierarchical structure, increased active sites and enhanced conductivity, the as-prepared electrocatalysts exhibit superior HER activity with low overpotentials, small Tafel slopes and long-time durability in both acidic and alkaline electrolytes. The overpotentials of 158 and 179 mV were required to drive HER current density up to 10 mA cm−2 in 0.5 M H 2 SO 4 and 1.0 M KOH, respectively. This work reports a highly efficient MoS 2 -based electrocatalyst for HER via fabricating hierarchical structure and doping Ni atoms. Image 1 [ABSTRACT FROM AUTHOR]