6533b86dfe1ef96bd12ca1c8
RESEARCH PRODUCT
Luminescence from nearly isolated surface defects in silica nanoparticles
Lavinia VaccaroFranco Mario GelardiL. SpallinoMarco Cannassubject
Surface (mathematics)Field (physics)ChemistryPhononNanotechnologyCondensed Matter PhysicsMolecular physicsCrystallographic defectAmorphous solidExcited statetime-resolved luminescence silica nanoparticles point defects vibronic transitions electron–phonon couplingGeneral Materials ScienceLuminescenceIntensity (heat transfer)description
A structured emission/excitation pattern, proper of isolated defects, arises in a vacuum from silica nanoparticles. The luminescence, centered around 3.0-3.5 eV, is characterised by a vibronic progression due to the phonon coupling with two localised modes of frequency ∼1370 cm(-1) and ∼360 cm(-1), and decays in about 300 ns at 10 K. On increasing the temperature, the intensity and the lifetime decrease due to the activation of a non-radiative rate from the excited state. Concurrently, the temperature dependence of the lineshape evidences the low coupling with non-localised modes of the matrix (Huang-Rhys factor S ~ 0.2) and the poor influence of the inhomogeneous broadening. These findings outline an uncommon behaviour in the field of the optical properties of defects in amorphous solids, evidencing that the silica surface can allocate luminescent defects almost disentangled from the basal network.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2015-08-25 | Journal of Physics: Condensed Matter |