No abstract

Calcination of aminopropylsilica spheres generates colloidal silica with tailorable luminescence properties depending on the calcination conditions. After calcining at 550°C for 20h, photoexcited luminescent colloidal silica exhibits a bright blue emission (λmax=375nm, 3.3eV) followed by a long-lifetime green photoluminescence centered around 500nm (2.5eV), which lasts for more than 10s at room temperature. Time resolved temperature studies indicate that the long-lifetime green photoluminescence can be fitted by a multiexponential decay function consisting of a regular exponential term and a stretched exponential term with a temperature independent beta parameter consistent with a hopping mechanism.