Rapid growth of ZnO hexagonal tubes by direct microwave heating

Abstract

Zinc oxide hexagonal tubular crystals were synthesized by direct microwave heating from ZnO powders within 5 min without any metal catalysts or transport agents. ZnO source materials were evaporated from the high-temperature zone in an enclosure, and crystals were grown on the self-source substrate in an appropriate condition. The ZnO vapor formed in the high-temperature zone can deposit and grow on the powders located in the low-temperature zone to form crystals. The scanning electron microscopy (SEM) reveals that these products are hexagonal tube crystals with 80 μm in diameter and 250 μm in length, having a well faceted end and side surface. A possible growth mechanism and the influence of reaction temperature on the formation of crystalline ZnO hexagonal tubes were presented. The photoluminescence (PL) exhibits strong ultraviolet emission at room temperature, indicating the potential applications in short-wave light-emitting photonic devices.

Photocatalytic CO2 reduction of C/ZnO nanofibers enhanced by an Ni-NiS cocatalyst

“…Moreover, the peak at 485 nm could be attributed to Zn vacancies. 62 The PL fluorescence intensity of the composites decreased significantly compared with that of C-Z, thus indicating that the composites have a lower e CB−h VB+ recombination rate. The minimal fluorescence intensity of C-ZNNS60 also indicates that this sample presents the best photocatalytic performance among the catalysts.…”

Effects of precursor concentration and reaction time on sonochemically synthesized ZnO nanoparticles

“…In Figure 4, all samples exhibit UV emission peaks at 396 nm in their PL spectra corresponding to the near bandedge recombination of excitons in ZnO [1,[23][24][25][26] . Two peaks at both ends of the visible region from interstitial atoms and vacancies 25 are also observed.…”

Effect of growth time on morphology and photovoltaic properties of ZnO nanowire array films

“…This is because they not only allow fundamental studies to improve the understanding of the chemical, electrical, and physical properties of one-dimensional nanostructures, but they may also be used as promising building blocks for a new generation of solar cells called DSSCs [4][5][6][7][8][9]. In order to further improve cell efficiency, the effective approaches currently applied are to control the morphology, orientation, crystal size, nanowire density and nanowire aspect ratio of ZnO-nanostructure films which can significantly increase dye loading and light harvesting [10][11][12], and to modify the surface of ZnO-nanostructure films which can suppress carrier recombination [13].…”