Optical properties of porphyrin molecules immobilized in nano-porous silicon

The paper aims at studying optical properties of porous silicon powders and thin films which were impregnated with different porphyrin molecules. It has been shown that introducing porphyrins into porous silicon matrix results in quenching of luminescence from porous silicon, while luminescence of porphyrins survives, though its structure changes. At the same time, porphyrins in porous silicon matrix which was preliminarily oxidized does not alter luminescence from porphyrins. Generation of singlet oxygen by illuminated porphyrin/porous silicon composite is confirmed by additional oxidation of porous silicon and by the observation of characteristic 1270 nm luminescence band.