Optical and Electrochemical Applications of Silicon–Carbon Dots/Silicon Dioxide Nanocomposites

Various colors of photoluminescent SiC-dots/SiO2 prepared through a simple heating process have been employed for optical and electrochemical applications. Blue (B)-, green (G)-, and tan (T)-SiC-dots/SiO2 powders have been prepared from SiC-dots that had been prepared from 3-aminopropyl trimethoxysilane through a hydrothermal route by simply controlling heating at 60 °C for 60 min and 300 °C for 10 and 20 min, respectively. The B-, G-, and T-SiC-dots/SiO2 nanocomposites emit at 455, 534, and 574 nm, respectively, under excitation at 360 nm. B-, G-, and T-SiC-dots/SiO2 glass films show at least seven colors when excited at 360, 460, and 520 nm. Through a heat-induced photoluminescence (PL) change, a representative lithographic pattern of B-SiC-dots/SiO2 films has been fabricated using a near-infrared laser. The B-, G-, and T-SiC-dots/SiO2 also possess high electrocatalytic activity for the oxygen reduction reaction. Having such interesting PL and electrical properties, the stable, low-toxic, and cost-effective B-, G-, and T-SiC-dots/SiO2 nanocomposites show great economic potential in many applications such as light-emitting diodes, photoluminescent windows, and fuel cells.