Observation of oxygen dimers via energy transfer from silicon nanoparticles

Abstract

Energy transfer from photo-excited excitons confined in silicon nanoparticles to oxygen dimers adsorbed on the nanoparticle surfaces is studied as a function of temperature and magnetic field. Quenching features in the nanoparticle photoluminescence spectrum arise from energy transfer to the oxygen dimers with and without the emission of Si TO(Δ) phonons and, also, with and without the vibrational excitation of the dimers. The dependence of the quenching on magnetic field shows that energy transfer is fast when a dimer is present, allowing an estimate of the proportion of the nanoparticles with adsorbed dimers.

Singlet oxygen generation by nanoporous silicon: photoluminescence dynamics in magnetic field

“…Thus, only sample 2 reveals ET assisted dominantly by the momentum-conserving TO phonon. This 1st replica below the resonance is interesting also from the other point of view: due to the indirect character of a Si exciton in NP, ET at one phonon below the resonance occurs as no-phonon process [24].…”