Structure and Photoluminescent Properties of ZnO Encapsulated in Mesoporous Silica SBA-15 Fabricated by Two-Solvent Strategy

Abstract

The two-solvent method was employed to prepare ZnO encapsulated in mesoporous silica (ZnO/SBA-15). The prepared ZnO/SBA-15 samples have been studied by X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, nitrogen adsorption–desorption isotherm, and photoluminescence spectroscopy. The ZnO/SBA-15 nanocomposite has the ordered hexagonal mesostructure of SBA-15. ZnO clusters of a high loading are distributed in the channels of SBA-15. Photoluminescence spectra show the UV emission band around 368 nm, the violet emission around 420 nm, and the blue emission around 457 nm. The UV emission is attributed to band-edge emission of ZnO. The violet emission results from the oxygen vacancies on the ZnO–SiO2interface traps. The blue emission is from the oxygen vacancies or interstitial zinc ions of ZnO. The UV emission and blue emission show a blue-shift phenomenon due to quantum-confinement-induced energy gap enhancement of ZnO clusters. The ZnO clusters encapsulated in SBA-15 can be used as light-emitting diodes and ultraviolet nanolasers.

Improvement of Cobalt Dispersion on Co/SBA-15 and Co/SBA-16 Catalysts by Ultrasound and Vacuum Treatments during Post-Impregnation Step

“…It was synthesized from block copolymer surfactant with organic silica as silica source under acidic condition. The SBA series are well-known mesoporous silica because of their high thermal and hydrothermal stability [17], high surface area, large pore volume [18], controllable porosity [19], and easy preparation.SBA-15 is one of most studies as catalyst support and separation because of its uniform pore size, hexagonal array of one-dimensional cylindrical channels, large surface areas, and high thermal stability [20]. However, the structure of the SBA-15 can be changed by using different solvents, surfactants or salt additions in the preparing step.…”

Nanostructured ZnO Materials: Synthesis, Properties and Applications

“…They have been widely employed in the literature as colloidal solutions for the preparation of thin films and seed layers for the further growth of vertically oriented nanowires; additionally they have been used as precursor for the 'oriented growth' of ZnO nanorods (as detailed in paragraph "Solution growth: Sol-gel hydrolysis and condensation method") [39]. One application is the anchoring of ZnO nanoparticles on other nanostructured and porous surfaces, mainly to enhance the luminescence properties [78,79]. Another possibility to employ ZnO nanoparticles is related to their use in medicine for drug delivery and anticancer agents [80].…”

ZnO–SiO2 core–shell nanorod composite: Microstructure, emission and photoconductivity properties

“…Several reports are available on the silica based ZnO nanocomposites grown by different synthetic procedures such as magnetron sputtering, chemical solution techniques, etc. [17][18][19][20][21][22][23][24]. Synthesis of ZnO nanoparticles confined in a matrix has been carried out mostly to harvest high luminescence properties at room temperature [19][20][21][22][25][26][27][28].…”