Photoluminescence from mesoporous silica: Similarity of properties to porous silicon

Photoluminescence (PL) from mesoporous silica (MS) with the pore size of si milar to6 nm and the thickness of walls among pores of similar to1 nm has b een studied at room temperature. The heat pretreatment of MS in air at diff erent temperatures and the variation of the excitation wavelengths allow on e to shift the PL peak through the whole visible spectral range. The PL is suggested to originate from nonbridging oxygens (red bands), hydrogen-relat ed species (green bands), and water-carbonyl groups (blue bands). The spect roscopic properties of MS are found to be similar to those of surface-oxidi zed silicon nanocrystals and porous silicon. (C) 2000 American Institute of Physics. [S0003-6951(00)00348-X].