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The near-infrared emitting materials have been widely used in portable near-infrared spectroscopy,solar cells,optical communication,environmental monitoring,etc.They mainly include phosphors doped with transition metal ions such as Cr3+,phosphors doped with rare earth ions such as Yb3+ and Eu2+,and semiconductor quantum dots such as Ag2S and PbS.Based on the above classification,this paper introduces the research progress of near-infrared emitting materials in recent years.

This article reviews the applications of rare earth functional materials.Rare earth is applied in some important fields,such as permanent magnets,luminescent materials,hydrogen storage materials,catalytic materials.Current problems in research and application are briefly discussed.The new research tendencys of rare earth materials in radiation protection and rare earth alloy are also discussed.

High luminance upconversion phosphors,Sr0.89Yb0.1Er0.01F2 and Sr0.8495Yb0.15Tm0.005F2,were synthesized via a high-temperature solid-phase synthesis.Underexcitation of 980 nmlaser,Sr0.89Yb0.1Er0.01F2 can emit red and green lights (yellow-green light) and Sr0.8495Yb0.15Tm0.005F2 can emit blue light.The emission intensities of the samplesarestronger than those of the commercial upconversion phosphors.The white lightemission materials with different color temperatures can be achievedvia mixing theabove two upconversion phosphors under different mass ratios.These materials have potential applications in security,the three-dimensional display,and white lighting.

The ZnO,CdS,and CdS/ZnO quantum dots have been successfully prepared through a facial sol-gel method.After annealing treatment,the CdS/ZnO core-shell structure with a ZnO shell of 10 nm was acquired.The CdS/ZnO core-shell structure resulted in the obvious red shift in the absorption band edge.Compared to those of ZnO and CdS,obvious changes were found in the excitation and emission spectra of CdS/ZnO and the luminescent intensity of CdS/ZnO increased due to the core-shell structure.Also,it was verified that the core-shell structure led to the change of the energy level structures.

A novel NIR quantum cutting phosphor,Bi3+-Yb3+ codoped GdVO4,has been prepared through a high temperature solid state method.Under UV excitation at 250~400 nm,it shows strong NIR emission ranging from 900 to 1 100 nm.NIR emission intensity of Gd0.87Yb0.1Bi0.03VO4 increased by 120% due to the introduction of Bi3+ ions,compared with that of Gd0.9Yb0.1VO4,and its excitation spectrum peak shifted from 323 nm to 341 nm.The broadened excitation band will favor its applications.Compared with the most efficient quantum cutting phosphor reported,YVO4:Bi3+,Yb3+,GdVO4:Bi3+,Yb3+ has much stronger visible and NIR emission,because Yb3+ ions are effectively excited through the charge transfer state from VO3-4 units and the energy transfer 1S0-3P1 from Bi3+.GdVO4:Bi3+,Yb3+ is believed to be a valuable phosphor with broad excitation band and strong NIR emission.

Monodisperse Y2O3 flower aggregates were obtained by selfassembly of nanotubes through rolling up the Y(OH)CO3 nanosheets without any templates under hydrothermal condition followed by an annealing process.Through decreasing the concentration of Y(CH3COO)3,homogeneous separated Y2O3 nanotubes with the length of(150 nm and the diameter of(40 nm and monodisperse(30 nm Y2O3 nanospheres were also selectively prepared.Doped Eu3+ ions don’t influence their morphologies.Under UV excitation,Y2O3:0.05Eu3+ flower-like and spherical samples show strong red emission,corresponding to the characteristic lines of Eu3+.

Iodine-incorporated BiOCl core-shell micro-spheres were first time fabricated using one-step approach under atmospheric pressure.Iodine anions were utilized as both structure directing agents for fabricating core-shell structure and doped ions incorporated in the framework of the core-shell BiOCl spheres to extend the light adsorption edge to visible light region.Super strong photocatalytic performance for this structure can be also obtained.This work provides a novel and easy pathway for creating advanced photocatalytic properties,serving as new promising functional materials for advanced water treatment technology.

Monodisperse ZnSn(OH)6(ZHS) microcrystallites(MCs) with two morphologies have been prepared through a facile preparation method without complicated steps,advanced experimental conditions or equipments.The morphology and compositional characteristics of the 3D hierarchitectures(HAs) of ZHS MCs were investigated by various techniques such as XRD,FESEM,TEM,UV-vis spectra,BET.In the reaction system the morphology evolution from cube to sphere was controlled with adding different concentration of NH4OH.The gas sensors based on ZHS exhibited a good gas sensitivity to HCHO.However,the gas sensors based on spherical ZHS MCs exhibited the higher sensitivity,shorter recovery time and good reproducibility to HCHO than those of cubic ZHS MCs.More importantly,it was found that spherical ZHS MCs with ~600 nm size had the best gas-sensing properties owing to more oxygen vacancy defects,less band gap energy,and larger active surface area.