Structural Origin of Visible Luminescence from Silica Based Organic−Inorganic Hybrid Materials

Abstract

We synthesized a series of n -octadecylsiloxanes having different empirical formulas, that is, R-SiO 3/2 (R = C 18 H 37 ), R-(CH 3 )SiO 2/2, and R-(CH 3 ) 2 SiO 1/2 . We found that the compound with the formula R-SiO 3/2 shows the highest PL emission with a quantum yield of 19 ± 0.5%, whereas the compound with the formula R-(CH 3 ) 2 SiO 1/2 hardly shows the PL output. The present results clearly demonstrate that carbon-related species are not responsible for the PL; rather, the PL emission results from some silicon/oxygen-related defect species. On the basis of the present experimental findings, a structural origin of the PL from silica based organic−inorganic hybrid materials is proposed.