The tunable emission characteristics of Er3+ doped and Er3+/Eu3+ co-doped Na5La(MoO4)4 phosphors prepared via high -temperature solid phase method were investigated. The microstructure of the modified phosphor was studied by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy, and its luminescence properties were analyzed by photoluminescence excitation and photoluminescence spectra. The energy transfer mechanism of Er3+ ions to Eu3+ ions was investigated by changing the concentration of Eu3+ ions to induce the spectral changes, and the photoluminescence decay lifetime was measured to validate the findings. Notably, under excitation at 380 nm, the co-doped phosphors exhibited tunable emission ranging from green to orange -red. Furthermore, Na5La(MoO4)4:0.04Er3+/0.04Eu3+ phosphor, when combined with a 380 nm chip, achieved desired warm white light emission. These promising results underscore the potential application of Na5La(MoO4)4:0.04Er3+/0.04Eu3+ phosphor in solid -state lighting.

Oxygen vacancies (VOs) play a pivotal role in promoting the photocatalytic activities of perovskite oxides. Herein, we proposed a simple and effective strategy of introducing both surface oxygen vacancies and bulk single electron trapped oxygen vacancies (SETOVs) into CaTiO3 by ethanol quenching. The purchased CaTiO3 was preheated at 800 degrees C and then the hot CaTiO3 was quenched in ethanol instantly. The ethanol-quenched QECaTiO3 delivers much improved photocatalytic activities towards both RhB degradation and hydrogen evolution under visible light irradiation by 6.5 and 65.2 times, respectively, in comparison with the pristine CaTiO3. Both the bulk SETOVs and surface VOs enhance light absorption, and the surface VOs serve as photocatalytic active sites. DFT calculations further reveal the narrowed band gap and accumulated charge density near the Fermi level in QE-CaTiO3, which help the visible light absorption, facilitate charge carriers generation and migration, and promote photocatalytic activities. Our findings provide an efficient and easily scalable approach to engineering oxygen vacancy defects in photocatalysts and other catalysts.

Near-infrared spectroscopy (NIRS) is a rapid, non-destructive analytical characterization tool. In this study, we report near-infrared (NIR) phosphor Ca3MgTiGe3O12:Cr3+ in garnet system, achieving ultra-broadband NIR emission. The emission spectrum of the phosphor ranges from 690 nm-1100 nm with a full width of half maximum (FWHM) value of similar to 127 nm. The emission peak is observed at 786 nm when the excitation wavelength is 463 nm. The broadband emission seen in this study was identified as a result of T-4(2) -> (4)A(2) transition of Cr3+ in host lattice. The internal quantum efficiency (IQE) of the material was found to be as high as 66.5 %. The energy transfer mechanism, quantum yield, thermal stability and preparation conditions of the material were further investigated. These studies show that these materials with highly-efficient ultra-brosd near-infrared emissions are promising candidates for high-quality near-infrared light sources.

Solar energy is considered sustainable green energy to prevent environmental pollution. Tungsten trioxide (WO3) is one of the attractive solar energy-driven photocatalysts and photocatalytic supports. Besides, Hydrogen (H) has a small size and can move into many inorganic compounds, and occupy the sites in microstructure as well, with little space structure expansion. H doping in semiconductors attracts more and more attention due to its effect of providing free carriers, resulting in localized surface plasmon resonances which can improve the utilization efficiency of solar energy. In our research, we developed a new method to prepare the H-doped WO3 whose color turned green, and to prepare Ag/HxWO3, which could extend the solar light response range to near-infrared. Furthermore, the photocatalytic activity to degrade RhB solution under UV light and visible light was both improved. The density of free electrons is based on the Drude model to discuss the mechanism of photocatalysis upon the visible. The contact of noble metal Ag and HxWO3 can play a vital effect in the separation of photogenerated electron-hole pairs. The localized surface plasmon resonances and green coloration bring the tungsten trioxide more remarkable performance together. Results showed that constructed photocatalysis of this work greatly enhanced the utilization rate of solar energy. Photocatalytic for the Degradation of liquid organic pollutants with HxWO3 is believed to have a bright feature.

Metal halide perovskite nanocrystals have excellent prospects in solid-state lighting, flexible display, sensing, and other optoelectronic applications due to their superb photoelectric properties (high quantum efficiency and fast carrier diffusion speed). However, they are susceptible to environmental factors such as ultraviolet radiation and polar solvents. Especially in a water environment, poor stability seriously restricts the application of perovskite optical devices. In this paper, a kind of porous polymer (ethylene-vinyl acetate copolymer, EVA) and perovskite nanocrystals were mixed to form perovskite nanocrystals-EVA composites. The obtained composites were aged in water for 21 days, and the fluorescence enhancement was 170 times. Even in a strongly acidic environment, the fluorescence enhancement was 91 times. The information encryption mode of the composite material can effectively encrypt information in a wet environment due to the change of light wavelength, making a white light-emitting diode (w-LED). This metal halide perovskite nanocrystals-EVA composite will unleash a wide variety of solid-state lighting and flexible display possibilities that are limited by the use of existing methods in humid and strongly acidic environments.

The as-prepared TPPDA-CoPor-COF shows high CO faradic efficiencies of 87–90% from −0.6 to −0.9 V vs. RHE, and the largest CO partial current density of TPPDA-CoPor-COF exceeds most of reported COF-based electrocatalysts.

TPE-CoPor-COF shows high FE CO (91–95%) in the range of −0.6 to −1.0 V, and a maximum j CO of −30.4 mA cm −2 at −1.0 V, exceeding most of reported COF-based electrocatalysts.

A bipolar-type 2D COF has been fabricated through the condensation of TPPDA and Cu-TFPP. The COF cathode with p- and bipolar-type redox-active centers exhibits good performance for Li-ion batteries.

Broadband NIR phosphors are urgently needed in NIR-LED and medical imaging. In this paper, a new type of near-infrared phosphor Li2Mg1-0.5xZr1-0.5xO4: xCr3+(0.6% < x < 1.6%) was synthesized by high temperature solid phase method. The optimal doping concentration of the phosphor is x = 1.0%, which exhibits broadband emission in the range of 600-1200 nm, and reaches the full width at half maximum (FWHM) of 205 nm under 462 nm blue excitation. The X-ray diffraction characterization results of the Li2Mg1-0.5xZr1-0.5xO4: xCr3+(0.6% < x < 1.6%) sample are refined and analyzed, and the doped sample is basically consistent with the pure phase. The sample was characterized by diffuse emission, and it was found that the sample matrix had intrinsic absorption. The thermal stability of Li2Mg0.995Zr0.995O4:1.0%Cr3+ phosphor was studied, and its relative intensity was 51.3% of room temperature at 100 ?C. The results show that this new type of ultra-wide near-infrared emitting phosphor has application potential in medical imaging and PC-LED directions.

In this paper, ZnWO4: La3+, Y3+ photocatalysts were synthesized by a high-temperature solid state reaction method. The effects of La3+ and Y3+ doping contents on the phase, morphologies and optical properties of the samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Diffuse reflectance spectra (DRS), photoluminescence spectra (PL), Raman and UV-visible spectroscopy, respectively. The as-prepared ZnWO4:La3+, Y3+ photocatalysts showed photoluminescence with a broad band emission, and high photocatalytic activity in degradation of rhodamine B (RhB) under simulated UV irradiation. The results showed that co-doping in ZnWO4 can enhance light harvesting capability to generate more electron-hole pairs, and acted as a trap center by decreasing the recombination of photogenerated electrons and holes. All the results obtained by the work suggest that ZnWO4: La3+, Y3+ photocatalysts are promising materials for the photocatalytic decomposition of pollutants.

设计了一种通过乙醇淬火来修饰纳米氧化铜表面的简单方法.首先将纳米氧化铜加热至800℃,然后立即浸入无水乙醇中淬火.通过罗丹明B的光催化降解表明,在紫外?可见光照射下,表面修饰后的纳米氧化铜比修饰前的纳米氧化铜具有更好的光催化性能.电子顺磁共振测试表明,通过快速的无水乙醇淬火,氧化铜中出现了高浓度的氧空位,这些氧空位有效地提升了氧化铜的光催化性能;X射线衍射和光电子能谱测试表明,通过无水乙醇淬火,氧化铜中出现了氧化亚铜和铜,这可能会形成CuO-Cu2O异质结以及Cu-CuO/Cu2O肖特基异质结,促进电荷?空穴分离,有效地提升改性氧化铜的光催化性能.实验表明溶剂淬火方法能有效地修饰金属氧化物的表面,增加氧化物中的表面氧空位,甚至形成异质结,提高材料的表面活性.

There are numerous approaches for modifying the surface structure of titanium dioxide (TiO2) crystals.

Ti4+-doped ZnWO4 phosphors were synthesized by a facile solid state reaction route. The structural and morphological features of the as-synthesized Ti4+-doped ZnWO4 photocatalysts were intensively characterized by XRD(X-ray diffraction), XPS(X-ray photoelectron spectroscopy), UV-vis DRS(Ultraviolet-visible diffuse reflectance spectrum), PL(photoluminescence spectroscopy). The photocatalytic reaction tests have been decomposed by the solution of rhodamine B(RhB). The results showed that the Ti4+-doped ZnWO4 phosphors had a high photocatalytic activity, and RhB degradation rate of 97% within 120 min was achieved for the 0.01Ti(4+)-doped sample. The enhancement of photocatalytic performance for Ti4+-doped ZnWO4 samples can be ascribed to reduce the recombination rate of photogenerated electron-hole pairs with the formation of new defects by Ti4+ doping. This study suggests that Ti4+-doped ZnWO4 photocatalysts are promising for photocatalytic decomposition of organic contaminants.

Modification of the surface properties of SrTiO3 crystals by regulating the reaction environment in order to improve the photocatalytic activity has been widely studied. However, the development of a facile, effective, and universal method to improve the photocatalytic activity of these crystals remains an enormous challenge. We have developed a simple method to modify the surface environment of SrTiO3 by ethanol quenching, which results in enhanced UV, visible and infrared light absorption and photocatalytic performance. The SrTiO3 nanocrystals were preheated to 800 °C and immediately quenched by submersion in ethanol. X-ray diffraction patterns, electron paramagnetic resonance spectra, and X-ray photoelectron spectra indicated that upon rapid ethanol quenching, the interaction between hot SrTiO3 and ethanol led to the introduction of a high concentration of oxygen vacancies on the surface of the SrTiO3 lattice. Consequently, to maintain the regional charge balance of SrTiO3, Sr2+ could be substituted for Ti4+. Moreover, oxygen vacancies induced localized states into the band gap of the modified SrTiO3 and acted as photoinduced charge traps, thus promoting the photocatalytic activity. The improved photocatalytic performance of the modified SrTiO3 was demonstrated by using it for the decomposition of rhodamine B and production of H2 from water under visible or solar light.

Multi-functional ferroelectric materials are the major topic of discussion in recent years. In order to study the photocatalytic property of ferroelectric materials, BiFeO3 and Bi1-xYxFeO3 nanostructure were prepared by sol-gel method. The crystal structure, morphology, chemical composition and other physiochemical properties of the samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). In addition, the ultraviolet-visible spectrophotometer and photochemical reactions instrument were applied to study the absorption and the photocatalytic property of the samples. The results show that doping of Y3+ can reduce the grain size and the forbidden band gap without changing the lattice structure. Also, according to the fitting analysis of XPS narrow spectrum of O 1s, it is found that the content of oxygen vacancies were increased after Y3+ doping. The oxygen vacancies can reduce the recombination rate of hole-electron pairs so that the utilization of carriers is improved. Therefore, the doping of Y3+ can increase the photocatalytic efficiency of BiFeO3, and it can be a promising photocatalytic material.

A series of Ln3+ (Ln3+ = Er3+/Dy3+) ions doped Na2NbAlO5 (NNAO) phosphors were synthesized by solid-state method. The Er3+ and Dy3+ ions doped phosphors were characterized by XRD, photoluminescence (PL) and decay profiles. The Ln3+-doped samples are consistent with the pure NNAO phase which is analyzed by the X-ray diffraction result. The PL graphs show that the intensity of luminescence increases with the increasing doping concentrations up to their critical certain values and then decreases at higher concentrations due to the concentration quenching effect of Er3+/Dy3+ ions. The energy level diagrams containing the positions of 4f and 5d energy levels of Er3+ and Dy3+ ions have been established and studied. In addition, under the ultraviolet light, the prepared NNAO:xLn3+ (Ln3+ = Er3+/Dy3+) phosphors show the characteristic green (Er3+), cyan (Dy3+) emission, respectively. Under the excitation of 365 nm, the quantum efficiencies of NNAO:0.01Er3+ and NNAO:0.03Dy3+ phosphors are measured to be 61.7% and 72.2%, respectively. The obtained results indicate that the new NNAO:xLn3+ (Ln3+ = Er3+/Dy3+) phosphors are promising applications in white-light emitting diodes field.

Oxygen vacancy defects play an important role in improving the light-capturing and photocatalytic activity of tungsten trioxide (WO3). However, the hydrogen treatment method that is commonly used to introduce oxygen vacancies is expensive and dangerous. Therefore, the introduction and control of oxygen vacancy defects in WO3 remains a challenge. Here, we demonstrated that oxygen vacancies could be successfully introduced into WO3−x while using a facile method through low temperature annealing in alcohol. The obtained WO3−x samples with optimal oxygen vacancies showed strong absorption of light, extending from the ultraviolet to the visible and near-infrared regions, and exhibits strong plasmon resonance from 400–1200 nm peaking at approximately 800 nm. When compared to pristine WO3, the photocatalytic activity of WO3−x was greatly improved in the ultraviolet and visible regions. This study provides a simple and efficient method to generate oxygen vacancies in WO3 for photocatalysis, which may be applied in the photoelectrochemical, electrochromic, and photochromic fields. Because oxygen vacancy is a common characteristic of metal oxides, the findings that are presented herein may be extended to other metal oxides.

Zn1-xWO4:xLi(+) (x = 0, 0.02, 0.05, 0.1) phosphors were synthesized by high-temperature solid-state method. The structural and luminescence properties of the samples were investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), Microconfocal Raman spectrometer(MR), Diffuse reflectance spectra (DRS) and Photoluminescence spectra. The Li-doped ZnWO4 phosphors show photoluminescence with a broad band. Compared with the pure ZnWO4, the band gap of lithium doped samples shows a red shift measured by Diffuse reflectance spectra (DRS), which could be attributed to the doping effects. Moreover, photocatalytic activity test shows that the Li-doped ZnWO4 phosphors exhibit higher catalytic activities than the pure ZnWO4 for the degradation of Rhodamine B by the UV irradiation. The result shows that the Li-doped phosphors can enhance light harvest capability to generate more electron-hole pairs, and act as a trap center by decreasing the recombination of photogenerated electrons and holes.

Black TiO2 has triggered worldwide research interest due to its excellent photocatalytic properties. However, the understanding of its structure–property relationships and a more effective, facile and versatile method to produce it remain great challenges. We have developed a facile approach to synthesize black TiO2 nanoparticles with significantly improved light absorption in the visible and infrared regions. The experimental results show that oxygen vacancies are the major factors responsible for black coloration. More importantly, our black TiO2 nanoparticles have no Ti3+ ions. These oxygen vacancies could introduce localized states in the bandgap and act as trap centers, significantly decreasing the electron–hole recombination. The photocatalytic decomposition of both rhodamine B and methylene blue demonstrated that, under ultraviolet light irradiation, better photocatalytic performance is achieved with our black TiO2 nanoparticles than with commercial TiO2 nanoparticles.