Electron Paramagnetic Resonance and Photoluminescence Study of Si Nanocrystals – Photosensitizers of Singlet Oxygen Moleculesстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Sinanocrystals formed by electrochemical porosifying of c-Si wafers are investigated by means of the electron-paramagneticresonance (EPR) and photoluminescence (PL) techniques. The PL spectra and transients give evidence of the photosensitization of singletoxygenmolecules by the energy transfer from excitons confined in Sinanocrystals to oxygenmolecules adsorbed on the nanocrystal surfaces. The EPR experiments show that the singletoxygen generation is accompanied by a slowing down of the spin-spin relaxation time of Si dangling bonds on the nanocrystal surfaces. This effect is explained by the transition of a large part of the adsorbed O2molecules in their ground (triplet) states to the excited (singlet) ones. The EPR data allow us to estimate the concentration of the photosensitized singletoxygenmolecules to be on the order of 1018 cm−3.