A nanocrystalline tungsten oxide photochromic thin film was prepared by colloid chemistry method. The microstructure, phase transition involved in the solution process, photochromic behavior, and mechanism of the film were investigated by means of transmission electron microscope, x-ray diffraction, ultraviolet-visible absorption spectra, and x-ray photoelectron spectra. It was found that the particle size and crystallinity of the thin film could be easily controlled by adjusting the concentration of oxalic acid in the colloid solution of tungsten oxide hydrate. With the increase of the oxalic acid concentration, the size of nanoparticles in the film decreased sharply, and meanwhile, a blue shift of the absorption peaks caused by the quantum size effect was observed accordingly. With the increase of the pH in the solution, tungsten oxide hydrate was gradually transformed into an oxided 12-tungstate with Keggin structure, which led to the change of photochromic property of the films. The photochromism of the film is believed to be due to the electron transfer between the different valence states of tungsten ions located in adjacent sites.

Raman microscopy was used to investigate microstructural properties of amorphous MoO3 thin films that had been subjected to a photochromic (PC) or electrochromic (EC) process. The Raman spectra changed reversibly when the films went through PC or EC coloration and decoloration cycles. Different molybdenum bronzes were produced with PC and EC treatments, as indicated by the shifts in the Raman bands. The same observation was made in the surface photovoltage spectral experiments. Hence, it was concluded that the microstructure of molybdenum bronze was affected by the coloration means (PC or EC process); the injected cations in an EC process were bonded to the triply coordinated O atoms, whereas the injected H+ ions in a PC process were bonded to both the triply coordinated and doubly coordinated O atoms. The size of the injected cations via EC processes had little effect on the microstructure of the colored films.

Large-scale pure titanate nanotubes were synthesized through the hydrothermal reaction between TiO 2 powders and concentrated NaOH under an unexpected high temperature of 240 °C, while it was generally claimed that it is impossible to form nanotubes at temperatures higher than 180 °C. The titanate nanotube was found to be an inevitable intermediate product, which finally transformed into a nanowire upon increasing the hydrothermal treatment duration. It was proven that the successive appearance of nanosheets, nanotubes, and nanowires are three unavoidable kinetic products of the reaction. Increasing the temperature could only accelerate the nanotube-nanowire transformation process but could not affect the sequence of the reaction events. The transformation kinetics from nanotubes to nanowires under different reaction temperatures was studied. Detailed studies indicate that this transformation process was accompanied by a coarsening process induced by both oriented attachment (OA) and Ostwald ripening (OR) mechanisms simultaneously; thereafter, the OA-OR cooperative mechanism was proposed.

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Indium-doped ZnO (IZO) films with low In content (<6 at. %) were fabricated by rf helicon magnetron sputtering. The uniformity of the composites was confirmed by elemental analysis. The formation of an In–Zn–O solid solution was verified using X-ray diffraction (XRD) patterns. A wide, high-transmittance region (400–2000 nm) and >80% transmittance in the window of fiber optics telecommunication (1.30–1.55 µm) were observed. The incorporation of indium enhances the optical transmission in the designated visible and infrared wavelengths. The optical band gap shows a slight blue-shift with increasing In doping which can be explained by the Burstein–Moss effect. The Urbach tail parameter E0 increases with increasing indium content, which coincides with the increase in the full width half maximum (FWHM) of (0002) planes in XRD patterns. A decline in crystal quality with In incorporation in IZO films is also confirmed from photoluminescence (PL) spectra.

Using the specified-dynamics (SD) Whole Atmosphere Community Climate Model (SD-WACCM), the effects of the Madden–Julian oscillation (MJO) on the midwinter stratosphere and mesosphere in the Southern Hemisphere (SH) are investigated. The most significant responses of the SH polar cap temperature to the MJO are found about 30 days after MJO phase 1 (P1) and about 10 days after MJO phase 5 (P5) in both the ERA-Interim data and the SD-WACCM simulation. The 200- and 500-hPa geopotential height anomalies in the SH reveal that wave trains emanate from the Indian and Pacific Oceans when the MJO convection is enhanced in the eastern Indian Ocean and the western Pacific. As a result, the upward propagation and dissipation of planetary waves (PWs) in the middle and high latitudes of the SH stratosphere is significantly enhanced, the Brewer–Dobson (BD) circulation in the SH stratosphere strengthens, and temperatures in the SH polar stratosphere increase. Wavenumber 1 in the stratosphere is the dominant component of the PW perturbation induced by the MJO convection. In the SH mesosphere, the MJO leads to enhancement of the dissipation and breaking of gravity waves (GWs) propagating as a result of wind-filtering change in the SH extratropics and causes anomalous downwelling in the middle and high latitudes of the mesosphere. The circulation thus changes significantly, resulting in anomalous cooling in the mesosphere in response to MJO P1 and P5 at lags of 10 and 30 days, respectively.

Single-composition (or single-phase) phosphors have been proposed as a new strategy to overcome the concerns of emission reabsorption and different degradation rates of the three primary phosphors for light-emitting diodes (LEDs) application. A series of Ce 3+ , Sm 3+ and Tb 3+ co-doped NaSrBO 3 phosphors were synthesized via a high temperature solid-state reaction. Upon near ultraviolet (NUV) excitation, 10 tunable emissions from violet to white in visible region were realized in NaSrBO 3 :Ce 3+ , Sm 3+ , Tb 3+ phosphors by controlling the dopant concentrations. Particularly, highly efficient white-light emission with a quantum yield as high as 48.2% was achieved. The energy transfer mechanism between Ce 3+ and Sm 3+ ions in NaSrBO 3 was found to be predominantly of dipole-dipole nature. Moreover, thermal quenching effect on the photoluminescence of NaSrBO 3 :Ce 3+ , Sm 3+ , Tb 3+ was comprehensively surveyed 15 over the range of 300-600 K, showing a good thermal stability for LEDs application. By integrating this single-composition white-emitting NaSrBO 3 :Ce 3+ , Sm 3+ , Tb 3+ phosphor with a 360-nm NUV chip, we fabricated a high-performance white LED (WLED), which exhibited an excellent color rendering index Ra of 80.1 and a correlated color temperature of 6731 K with CIE coordinates of (0.311, 0.314). These findings demonstrate that the proposed single-composition white-emitting NaSrBO 3 :Ce 3+ , Sm 3+ , Tb 3+ 20 phosphors can serve as a promising phosphor for NUV-excited WLEDs.