Room temperature photoluminescence property of boron-doped sol–gel silica

Room temperature photoluminescence (PL) of boron-doped silica synthesized by a combined sol–gel and heating process has been investigated. The broad PL band has been resolved into three components centered at 3.7, 3.35 and 2.7 eV, which are assigned to non-bridging oxygen hole centers (NBOHC), carbon-related impurity, and two-fold coordinated silicon atoms, respectively. The intensities of the 3.35 and 2.7 eV bands decrease with the heating temperature increasing, due to oxidation of the corresponding luminescent centers. The effect of boron doping on the formation of intrinsic defects in silica is discussed.