•Ga- and In-doped ZnO nanorods were prepared by hydrothermal method and annealed in diluted hydrogen atmosphere.•Dramatically enhanced ultraviolet and suppressed visible emissions are demonstrated in these samples under ultraviolet or X-ray excitation.•An intense superfast ultraviolet luminescence is achieved in vertically aligned ZnO:Ga nanorod arrays.The Ga- and In-doped ZnO nanorods were prepared by hydrothermal method, and the effect of the hydrogen annealing on their morphology, structure and luminescence properties was investigated in detail. The results indicated that the annealing treatment resulted in the improvement of the surface roughness and the crystallization of the nanorods. Furthermore, the hydrogen-annealed nanorods exhibited a significant enhancement of the ultraviolet emission and simultaneous suppression of the visible emission under ultraviolet and X-ray excitation, as well as a sub-nanosecond fluorescence decay time. It means that these nanorods are expected to be promising candidates for applications in superfast and high-spatial-resolution X-ray imaging detectors.Enhanced X-ray excited luminescence of (a) Ga- and (b) In-doped ZnO nanorods annealed in H2/Ar atmosphere.Figure optionsDownload full-size imageDownload high-quality image (93 K)Download as PowerPoint slide

•A slightly etching appeared on the surface of Ga- and In-doped ZnO nanorods after annealing at 1000 °C.•The doped ZnO nanorods exhibited a strong visible emission band with a blue-shift under X-ray excitation.•An intense superfast ultraviolet emissions were observed after further hydrogen annealing.Ga- and In-doped ZnO microrods were prepared by low temperature hydrothermal process, and the effect of annealing temperature on morphology, crystallization, photoluminescence and X-ray excited luminescence were deeply researched. The results showed that both Ga- and In-doped ZnO microrods were possessed of a good crystalline quality and exhibited an intense visible emission band with a blue-shift under X-ray excitation. This blue-shift of the visible luminescence could be ascribed to the different contributions of the defect emissions, i.e. the increase in the oxygen vacancy (VO) emission and the decrease of the oxygen interstitial (Oi) emission. Moreover, a strong ultraviolet luminescence was also obtained by further hydrogen annealing. It is expected that Ga- and In-doped microrods are promising candidates for development of fast and high-spatial-resolution X-ray imaging detectors.

•Enhanced luminescence by ion codoping in LSO:Ce phosphors was comprehensively investigated.•The codopants prefer to occupy interstitial at sites and serve as electron donors.•The origin of enhanced luminescence was proposed based on the results of XANES spectra.•The magnitude of luminescence enhancement is closely related to the electronegativity of the codopant.(Lu0.995−xMxCe0.005)2SiO5 (M=Li, Mg and Sc, x=0.00–0.01) phosphors were synthesized via a sol–gel technique, the luminescence enhancement effect by Li+, Mg2+, or Sc3+ codoping is comprehensively investigated by XRD, Raman, thermoluminescence and X-ray absorption near edge structure (XANES) spectra. The underlying reason of enhanced luminescence by ion codoping is revealed, and a mechanism of the luminescence enhancement effect based on the valence state variation of cerium is proposed. It can be safely concluded that the enhanced luminescence of Lu2SiO5:Ce3+ by ion codoping essentially originates from the increase in the population of Ce3+, which is directly proved by XANES. The difference in luminescence enhancement effect for different codopants can be reasonably explained by the electronegativity of the codopant.