Optical Characteristics of C/0.5Al_2O_3-0.5P_2O_5-100SiO_2 Gel Glasses Prepared at Different Temperatures

0.5Al2O3-0.5P2O5-100SiO2 gels containing organic group (OC2H5) were synthesized through partial hydrolysis of alkoxide. The gels were calcined at 300-700℃ in N2 atmosphere, in which - OC2H5 was carbonized to form carbon nanoparticles with various sizes. Their absorption and photoluminescence spectra were measured. The absorption edge shifts to the higher-energy side as the size of the carbon particle decreases. This phenomenon was interpreted in terms of a quantum confinement effect of electron and hole in the carbon nanoparticles. The gel glasses doped with carbon nanoparticles show a strong and broad room-temperature photoluminescence with a peak located around 586nm under the excitation of 532nm line of a Nd:YAG laser. The position of photoluminescence peaks shifts hardly with changing the size of carbon nanoparticles. The photoluminescence spectra are originated from the surface of carbon nanoparticles or interfacial layer between it and gel matrix. The carbon nanoparticles are amorphous carbon nanoparticle in the gel glasses by the X-ray diffraction, high-resolution transmission electron microscopy and Raman spectra.