Synthesis, charaterization and optical properties of nanostructured silica hybrid materials obtained by soft chemistry from perhydropolysilazane/1,2,4-triazole precursors

Abstract

Nanostructured silica hybrid materials have been synthesized via soft chemistry way, by the incorporation of functional 1,2,4-triazole components into a silica network, using a perhydropolysilazane (PHPS) as a silica source and 1,2,4-triazole components as templates. The compositions, morphological and textural properties of the as-synthesized samples have been studied by 13C and 29Si CP MAS NMR, FTIR and SEM. The spectroscopy results suggest that the organic moieties have been chemically linked to the silica skeleton leading to hybrid materials in which Si–N, Si–O and Si–S bridges are created. Nitrogen adsorption-desorption analysis (BET) shows that the surface area varied between 385 and 425 m2 g−1. The 29Si CP-MAS NMR displays signals between -70 and -120 ppm corresponding to Q2, Q3 and Q4 units. The optical properties have been studied also by UV–visible diffuse reflection spectroscopy and photoluminescence (PL). This study reveals that the direct gap energies varied between 0.71 and 2.53 eV. Photoluminescence shows that the silica nanohybrids are suitable to the emission of blue light with wavelength (λem) values of about 470-480 nm. The PL emission results also from some silicon/oxygen-related defect species.