Luminescence quenching of fire retardant silica based chromophores

Nano silicon dioxide (SiO2) is one of the potential materials for fire retardancy. The chromophores extracted from silica spheres having emission maximum at 435 nm and 530 nm show the luminescence quenching by concentration due to the low excitation rate and no luminescence quenching by concentration due to the very large excitation rate, respectively. The formation of photoluminescent chromophores is strongly dependent on the combination of solvents. The diameters of silica spheres synthesized with 1:1 wt. ratio and 15:1 ratio of acetone and ammonium hydroxide were uniform and diverse, respectively. Although the luminescent chromophores were formed after 40 days for silica spheres synthesized with 15:1 ratio of acetone and NH4OH, the chromophores were not formed for fire retardant silica spheres synthesized with 1:1 ratio of acetone and NH4OH. The high resolution transmission electron microscope image shows the well-organized one directional crystal structures of the chromophores.