No abstract

Intense blue persistent luminescence (PersL) with sufficiently long duration time was firstly observed in SiO 2 particles after calcination with carbon. In indicates that the intense PersL of the optimal SiO 2 sample calcinated with carbon (1:2) at 600 °C can be recorded for about 1 h (0.32 mcd/m 2 ) and is actually visible for even more than 3 h by the dark-adapted vision in darkness. It reveals that the defects formatted during the calcination with carbon should be associated with oxygen vacancies and they play very important roles as emitters and traps, contributing to the PersL. The depth of the dominant traps in the optimal SiO 2 sample is calculated to be about 0.71 eV, which is 2 in a suitable range for PersL (0.5-0.8 eV).