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Near-infrared (NIR) luminescent materials have unparalleled advantages in certain fields, such as anti-counterfeiting. Nd3+ ion doped Gd2O3 near-infrared phosphor was successfully prepared by co-precipitation method and high-temperature solid-phase reaction. The structure and morphology of Gd2O3:Nd3+ cubic phase phosphors were studied in detail. The prepared phosphor was optically analyzed by fluorescence spectrometer. The research results show that with the increase of the Nd3+ doping concentration, the luminous intensity of the near-infrared phosphor in the near-infrared region shows a trend of first increasing and then decreasing. When the Nd3+ ion doping concentration is 1.0 mol%, the obtained phosphors have the best luminous intensity in the near-infrared region under the excitation of 808 nm laser. Gd2O3:Nd3+ phosphor emits near-infrared light due to the intra-4f transitions of Nd3+ ions. The concentration quenching theory is used to prove that the concentration quenching of Gd2O3:Nd3+ belongs to the cross relaxation caused by electric multipole. Due to the unique optical properties of this near-infrared phosphor, it is expected to be further developed in the field of fluorescent materials.

Eu3+-activated BaLaMgNbO6 red-emitting phosphors were synthesized by a high-temperature solid-state reaction method. Phase analysis and luminescence were characterized by X-ray diffraction (XRD) and photoluminescence excitation and emission spectra. The XRD patterns showed that BaLaMgNbO6 had a monoclinic structure with space group P21/n. The excitation spectra consisted of a broad charge-transfer band and some sharp f-f absorption peaks characteristic of Eu3+. The intensity ratio of I615/I590 was used to detect the chemical environment of Eu3+. The chromaticity coordinates of BaLa0.7Eu0.3MgNbO6 were (0.67, 0.33), indicating that the BaLaMgNbO6:Eu3+ phosphors were excellent red-emitting phosphors. Under excitation by near-ultraviolet (UV) and blue light, the phosphor not only exhibited intense red emission but also showed high color quality. The Ozawa and Dexter energy-transfer theories were employed to calculate the theoretical quenching concentration and determine the concentration quenching mechanism. In addition, the activation energy of BaLa0.7Eu0.3MgNbO6 was calculated through the Arrhenius equation. A configurational coordinate diagram was used to explain the thermal quenching mechanism.

A series of Eu 3+ ions activated double perovskite CaLaMgSbO 6 phosphors were successfully synthesized. Crystal structure was investigated by XRD and the results showed that this double perovskite exhibited rock-salt ordering of B-site ions. High-resolution transmission electron microscopy was used to prove the existence of B-site ordering. Thereafter, luminescence properties of the as-prepared powders were discussed in detail. The phosphors could be well excited by ultraviolet, near ultraviolet, and blue light. The quenching concentration for the transition of 5 D 0 - 7 F 2 reached up to 50.0 mol%. The theoretical quenching concentration and quenching mechanism were discussed in detail. Excellent thermal stability of this double perovskite phosphor was obtained and the quenching mechanism was investigated based on the configurational coordinate diagram. The CIE coordinates showed that this double perovskite phosphor had great potential in solid state lighting.

Crystal structures of Sr 1- x Ca x LaMgSbO 6 :Eu 3+ phosphors were studied in detail. Both the SrLaMgSbO 6 and the CaLaMgSbO 6 have a monoclinic ( P 2 1 / n ) structure. With increasing the Ca 2+ concentration, the peaks gradually divided and the phase changed from SrLaMgSbO 6 to CaLaMgSbO 6 . The symmetry of La 3+ in SrLaMgSbO 6 is lower than that in CaLaMgSbO 6 . Eu 3+ ions, as the structural probes, were selected to study the structure. Lifetimes and intensity ratio were used to study the symmetry in the structure. Thermal quenching of the phosphors was discussed from 323 K to 473 K. The emission intensities of 5 D 1 → 7 F J and 5 D 0 → 7 F J damped in different ratios while increasing temperature. The configurational coordinate diagram was used to explain this interesting phenomenon.

Heavy rare-earth oxysufide Er2O2S was successfully synthesized by using Na2CO3 as flux. The assumed phase evolution processes were verified by the calculation of thermodynamics and the analysis of TG/DSC, XRD, UV–vis, EDS and XPS. The role of Na2CO3 in reaction was proved to be attributed to enhance the chemical potential of S via reacting to form Na2S2O3 and Na2S. The reaction processes were proved to be possible in thermodynamics. The flux Na2CO3 could generate oxygen vacancy due to the formation of $$Na_{{Er}}^{{ \times \times }}$$ . The band gap, lattice volume and oxygen 1s XPS spectra were investigated to explore the existence of oxygen vacancy. The oxygen vacancy enhanced the stability of Er2O2S crystal structure and could realize the synthesis at a higher temperature. Thus, Na2CO3 not only promoted the preferential formation of Er2O2S but also could effectively stabilize the hexagonal structure of Er2O2S. Meanwhile, compared with K2CO3, Er2O2S/ polymethyl methacrylate (PMMA) coating exhibited a better absorbing property with Na2CO3 as flux.

Sm2(C2O4)3∙10H2O was prepared by coprecipitation method with Na3Cit as chelating agent. The microstructures were studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). The 1060 nm laser absorption properties were characterized by spectrophotometer. The results showed that the composition and morphology of Sm2(C2O4)3∙10H2O could be tuned by varying the molar ratio of Na3Cit to Sm3+ and the aging time. Then, the 1060 nm laser absorption properties were optimized. The spectral reflectivity at 1060 nm was low to 0.831 when the molar ratio of Na3Cit to Sm3+ was 1.2 and the aging time was 24 h. The as-prepared Sm2(C2O4)3∙10H2O can be applied as an effective laser absorber.

Eu3+ ions activated BaLaMgSbO6 phosphors were successfully synthesized by the solid-state reaction method using NH4Cl as the flux. The BaCl2 was selected to substitute BaCO3 as the starting material to attest that NH4Cl not only reacted with BaCO3 but also reacted with other starting materials. The analysis of TG/DSC was used to probe the role of NH4Cl flux in the process of synthesizing BaLaMgSbO6 powders. The crystal structure was investigated by XRD and Rietveld refinement, and the morphology by SEM. The phosphors had monoclinic double perovskite structure with the space group P21, as well as the rock-salt ordering of B-site. The luminescence properties, including the photoluminescence excitation and emission spectra, and the color coordinates were investigated. Also, the relationship between the crystalline size and the emission intensity were discussed. With increasing the calcination temperature, both the crystalline size and the emission intensity monotonously increased. The relative intensity ratio of red/orange emission was used to measure the degree of distortion from the inversion symmetry of the local environment of the Eu3+ ions in BaLaMgSbO6.

ZnO nanofibers (NixZn(1 − x)O with x = 0.03, 0.05, 0.07, 0.09) have been prepared by electrospinning method. The structural, morphological, static magnetic properties and microwave absorption properties are investigated in detail. The as-prepared samples show hexagonal wurtzite structure. However, the lattice constants decrease with the increase of Ni doping cotent, which result in the shrunk of the diameter of nanofibers. The static magnetic properties and microwave absorption properties can be tuned by varying the Ni content. The maximum saturation magnetization is obtained when x = 0.07 due to cation percolation threshold. The dielectric loss properties could be attributed to the dipole polarizations and interface polarization. The magnetic loss properties are mainly caused by natural resonance and exchange resonance. In addition, the networks of NixZn(1 − x)O nanofibers also benefit dissipating electromagnetic energy. The refelection loss (RL) of Ni0.07Zn0.93O nanofibers reaches −2.7 dB at 7.6 GHz and the electromagnetic wave absorption less than −2 dB is found to reach 3.1 GHz for an absorber thickness of 4.5 mm.

1064 nm laser stealth absorbent Sm2O2S was prepared by solid state flux method. The effects of doping Er3+ and Tm3+ on the powder’s phase compositions and reflecting property were investigated. The phase composition, morphology and reflectivity of powders were characterized by X-ray diffraction, scanning electron microscopy and ultraviolet visible spectrophotometer (UV-3600PC). The results exhibited that doping Er3+ and Tm3+ cause no significant changes on crystal structure. However, the morphology of powders changed a lot after doping Er3+/Tm3+, which influenced on the reflecting property. Because of the characteristic absorption of Er3+ and Tm3+, the reflectivity of Sm2O2S powders decreased in different degrees. The doping amount of Er3+ was 15 mol%, the lowest reflectivity 0.7450 % was obtained. The optimized doping amount of Tm3+ was 10 mol% and the reflectivity was 0.7403 %.

ZnO nanofibers were fabricated by electrospinning method. The morphology and microstructure of the as-prepared ZnO nanofibers were studied in details. The ZnO nanofibers showed pure polycrystalline phase with the hexagonal wurtzite structure. The average diameter of the ZnO nanofibers, calcined at 550 °C, was around 140 nm. Moreover, the electromagnetic loss properties of the as-prepared ZnO nanofibers were investigated. The mechanism of dielectric loss could be attributed to the electric dipolar polarization and interface polarization. The mechanism of magnetic loss properties were mainly caused by natural resonance and exchange resonance. The networks of ZnO nanofibers also facilitated dissipating electromagnetic energy. The dielectric loss factor tanδe was around 0.06085 and the magnetic loss factor tanδμ was approximate 0.04095. The as-prepared ZnO nanofiber exhibited excellent electromagnetic loss properties and it could be usd as a potential candidate for lightweight microwave absorption material.

A novel 1.54 μm laser absorbent of Er2O2S was prepared by solid state flux method. The effects of different calcining temperatures and preservation time on the synthesis and reflecting property of Er2O2S were investigated. The mechanism of fluxing agent was assumed and proved. The phase composition, morphology, and reflectivity of the powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet visible spectrophotometer (UV-3600PC). The results showed that pure phase of Er2O2S could be obtained with Na2CO3 as fluxing agent at 800–1200 °C, too high temperature and too long preservation time were bad for synthesizing Er2O2S. Na2CO3 played an important role during the reaction, the elemental sulfur in Er2O2S came from Na2S2O3 indeed. Different calcination conditions had a great impact on particle morphology, which had influence on the reflectivity of the products. The reflectivity was the lowest (0.39 %) when the calcining temperature was 1200 °C.

In this paper, the aluminum/polymer composite coating was prepared and the infrared emitting properties and environmental stability performance of the as-prepared coating were studied. The factors, such as polymer binders, pigment/binder ratios, preparation technology and coating thickness were investigated in detail. Firstly, the study of the polymer binders indicated that modified fluorocarbon resin was the best candidate due to its low infrared emissivity and well-performed physical and chemical properties. Secondly, the optimal pigment/binder ratio was 1.25:1. Thirdly, the optimum coating thickness was 75 μm and the scrape coating method was suitable to prepare the coating. Finally, the optimized aluminum/polymer composite coating showed low infrared emissivity of 0.31. The adhesive force of the coating was first grade and the impact resistance was more than 50 kg cm. In addition, it exhibited excellent salt, acid and alkali resistance. The as-prepared aluminum/polymer composite coating can be used as infrared stealth coating in the wavelength of 8–14 μm.

A series of double perovskite (Gd0.85-xLux)2MgTiO6: 0.3Eu3+ red phosphors were prepared via a typical high temperature solid-state reaction. XRD and HRTEM exhibits that the phosphors well crystallized as a double perovskite with the space group of P21/n symmetry. The luminescent properties of samples were investigated via excitation and emission spectra. The phosphors emit strong red light and weak orange red light under ultraviolet (UV) and near-UV excitation suggesting that Eu3+ ions situated in the sites without inversion symmetry. The UV–vis spectra included a broad host absorption band assigned to O2--Eu3+ and some peaks at 395 nm, 465 nm and 533 nm attributed to the typical f-f transition of Eu3+. The CIE chromaticity coordinates of all samples were near to the standard red light, indicating that the (Gd0.85-xLux)2MgTiO6: 0.3Eu3+ was a potential candidate material for red emitting phosphors. The decay curves matched with the lines fitted by a one exponential decay formula and the decay time increased with increasing Lu3+-dopant concentration within x

Double perovskite KLaMgWO6:Eu3+ phosphors were successfully synthesized by an improved sol–gel method using citric acid and polyethylene glycol as complexing agents. The structure evolution and photoluminescence were systematically invested by X-ray diffraction, Rietveld refinement and fluorescence spectra. The structure of Eu3+ doped samples was double-perovskite with space group C2/m. Enhanced luminescence properties were gotten by adding 5.0 wt% PEG. Na+ with smaller radius was selected to substitute K+ in this novel host. With increasing the concentration of Na+, the tolerance factors decreased and the structure of BO6 tilted gradually and lowered structure symmetry. Then the emission intensity ratio of 5D0–7F2/5D0–7F1 transition increased and the red emission played the dominate role. Also the emission intensity was enhanced by increasing the concentration of Na+. The phosphors showed better color purity with better CIE chromaticity coordinates. Therefore the synthesized phosphors is a potential light conversion red material for light emitting diode.

Ho(AcAc)3 modified ZnO quantum dots (QDs) were successfully prepared via a conventional method. The FTIR spectra were taken to explore the combination of Ho(AcAc)3 and ZnO QDs. The addition of Ho(AcAc)3 could lower the emission intensity of ZnO QDs by modifying the defects of ZnO QDs. Three types of ZnO QDs with different optical defects were used to composite with Ho(AcAc)3. The effect of Ho(AcAc)3 on different optical defects in ZnO QDs was distinctive. Ho(AcAc)3 modified ZnO QDs were successfully composited with the epoxy resin. With the addition of ZnO QDs, the emission intensity and UV absorption increased. Samples with Ho(AcAc)3 had higher visible light transmittance than those without Ho(AcAc)3. As such, Ho(AcAc)3 could improve the dispersity of ZnO QDs in epoxy. Thus, Ho(AcAc)3 could act as a compatibilizer between ZnO QDs and epoxy resin.