White Luminescence from Sol-Gel-Derived SiOC Thin Films

A new approach to obtain visible luminescence from sol-gel-derived SiOC films is proposed. In order to investigate the influence of Si and C content, Si- and C-rich SiOC films were prepared as well as stoichiometric SiOC films. High intense white luminescence is obtained where the emission color can be controlled by the experimental parameters such as the starting sol-gel-composition and the pyrolysis temperature. In stoichiometric SiOC films, low pyrolysis temperature yields UV-blue luminescence, whereas high temperatures favor green-yellow luminescence. On the contrary, in Si-rich SiOC films, intense white luminescence is obtained with a broad emission from 430 to 900 nm and an external quantum efficiency (EQE) of 11.5%. Relatively, stoichiometric SiOC films showed an EQE of 5%. Finally, C-rich SiOC films did not show noticeable luminescence due to absorption by carbon clusters.