A spherical mono-dispersed silica nano-particle system has been prepared by sol-gel method. After surface modification fluorescent organic chromophore was introduced onto the particle surface. The steady state photophysical behavior of this system in different mediums has been studied carefully. The results indicated that the structural characteristics of organic chain attached and the dispersed situation of organic chromophore on surface both were the main factors for the photophysical behavior of suspension studied. These results will be important and beneficial for the design or development of this system used as a fluorescence chemical sensor.

Key words: SOL-GEL PROCESS, SILICON DIOXIDE, SENSORS, CHEMICLAL MODIFICATION