TY - JOUR
T1 - Luminescence from nearly isolated surface defects in silica nanoparticles
AU - Spallino, Luisa
AU - Vaccaro, Lavinia
AU - Gelardi, Franco Mario
AU - Cannas, Marco
PY - 2015
Y1 - 2015
N2 - 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 evidencesth e 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 uncommonbehaviour 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.
AB - 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 evidencesth e 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 uncommonbehaviour 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.
KW - electron–phonon coupling
KW - point defects
KW - silica nanoparticles
KW - time-resolved luminescence
KW - vibronic
transitions
KW - electron–phonon coupling
KW - point defects
KW - silica nanoparticles
KW - time-resolved luminescence
KW - vibronic
transitions
UR - http://hdl.handle.net/10447/166030
M3 - Article
VL - 27
JO - JOURNAL OF PHYSICS. CONDENSED MATTER
JF - JOURNAL OF PHYSICS. CONDENSED MATTER
SN - 1361-648X
ER -