TiO₂/reduced graphene oxide (rGO) nanocomposites with two different TiO₂ particle sizes were synthesized by a facile hydrothermal method using two different source materials of Ti: tetrabutyl titanate (TBT) and commercial TiO₂ powder (P25). For respective series with the same source materials, we investigated additions that optimized the nonlinear optical properties (NLO) and optical limiting (OL) performances, and we explored the relationships between structural diversity and performance. Several characterization techniques, including X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and diffuse reflectance ultraviolet-visible spectroscopy (UV-Vis) were conducted to confirm the microstructures and chemical states of as-prepared materials. This indicated the existence of the Ti–O–C bond between rGO sheets and TiO₂ particles and the reduction from precursor graphene oxide (GO) to rGO. The results of UV-Vis spectra revealed that the TiO₂/rGO nanocomposites showed smaller band gaps than bare TiO₂. A nanosecond open-aperture Z-scan technique at 1064 nm was applied to investigate NLO and OL properties. TiO₂/rGO nanocomposites exhibited enhanced NLO and OL performances, arising from synergistic effects, compared to individual components. The TBT series samples performed better than the P25 series, presumably relevant to dimensional effects.

This work involves the introduction of niobium oxide into lanthanum aluminate (LaAlO₃) via a conventional solid-state reaction technique to yield LaAlO₃:Nb (LaNb_xAl_1−xO_3+δ) samples with Nb⁵⁺ doping levels ranging from 0.00 to 0.25 mol%. This study presents a comprehensive investigation of the effects of niobium doping on the phase evolution, defect control, and reflectance of LaNb_xAl_1−xO_3+δ powder. Powder X-ray diffraction (XRD) analysis confirms the perovskite structure in all powders, and XRD and transmission electron microscopy (TEM) reveal successful doping of Nb⁵⁺ into LaNb_xAl_1−xO_3+δ. The surface morphology was analyzed by scanning electron microscopy (SEM), and the results show that increasing the doping concentration of niobium leads to fewer microstructural defects. Oxygen vacancy defects in different compositions are analyzed at 300 K, and as the doping level increases, a clear trend of defect reduction is observed. Notably, LaNb_xAl_1−xO_3+δ with 0.15 mol% Nb⁵⁺ exhibits excellent reflectance properties, with a maximum infrared reflectance of 99.7%. This study shows that LaNb_xAl_1−xO_3+δ powder materials have wide application potential in the field of high reflectivity coating materials due to their extremely low microstructural defects and oxygen vacancy defects.

To improve the integrative properties of ZrO2-TiO2 optical film, polyvinylidene fluoride (PVDF)/ZrO2-TiO2 film was coated on the K9 glass substrate by Sol-Gel method using ZrOCl2·8H2O and Ti(OBu)4 as precursor of Zr and Ti, respectively. Using PVDF as organic additive, PVDF/ZrO2-TiO2 optical films were characterized by SEM, FT-IR and contact angle. Then the optical properties of the PVDF/ZrO2-TiO2 optical films were investigated via Ultraviolet/ Visible/Near Infrared transmission spectrum, optical band gap (Eg) and refractive index. SEM images indicate that the optical films are successfully prepared on the glass substrates. The addition of PVDF in the optical films increases the contact angle between water and the films. Eg of ZrO2-TiO2 optical films are slightly widened with the increasing of ZrO2 content, and Eg of PVDF/ZrO2(50mol%)-TiO2 films are widened as the mass fraction of PVDF increases. In addition, refractive indexes of ZrO2-TiO2 optical films increase as the mole fraction of ZrO2 decreases, and refractive indexes of PVDF/ZrO2(50mol%)-TiO2 films increase as the mass fraction of PVDF increases

CsBr: (Eu2+, KOH) powders were prepared by solid-state reaction. The photo luminescence (PL) spectra, photostimulated luminescence (PSL) spectra, Raman spectra and PSL lifetime spectra were systematically investigated, and the influence of KOH-adding on photostimulated luminescence and radiation hardness properties were discussed. The results reveal that the probability of radiationless transition increase due to hydroxyl ion (OH-), with the increasing of concentration of KOH, the PSL decay time of CsBr:(Eu2+,KOH) shortens gradually. Furthermore, the vacancy concentration around Eu2+ decreases due to the existence of K+ and OH-, which avoid the concentration quenching by the aggregation of Eu2+ and improves the radiation hardness of CsBr: Eu2+