Near-infrared photoluminescence of PbS QDs precipitated in the glass matrix

Abstract

Optical properties of PbS quantum dots (QDs) precipitated inside the oxide glass matrix were investigated. Photoluminescence (PL) spectra were recorded with peak wavelengths located at 1170-1680 nm with peak width of 150-500 nm. Radii of QDs in glasses were 2.0-3.7 nm depending upon the thermal treatment conditions. Changes in temperatures and excitation intensities resulted in the shift of photoluminescence bands as large as 70 nm, due to the laser-induced local heating. Photoluminescence from PbS QDs showed darkening and brightening behavior. Intensity of the photoluminescence increased with time at low temperature (< 150 K) especially when the excitation intensity was low. Photo-darkening was observed when temperature and/ or illumination intensities increased. Competition between the photo-brightening and photo-darkening determined the final steady-state photoluminescence intensity.

Compositional Dependence of CdSe Quantum Dot Formation on Silicate Host Glass Composition

“…Chemically synthesized quantum dots (QDs) require special organic passivation layers and buffering solutions to avoid agglomeration and these extra measures restrict lifetimes and practical applications of powdered QDs . On the other hand, QDs formed within a glass matrix via conventional melt‐quenching and subsequent heat treatment have an inorganic local environment that lessens the difficulties associated with chemically driven QDs and thus have been extensively studied . Glasses embedded with PbS and PbSe QDs, for instance, can give broad and controlled emissions at an optical telecommunication window (1.2–1.7 μm) .…”

“…On the other hand, QDs formed within a glass matrix via conventional melt‐quenching and subsequent heat treatment have an inorganic local environment that lessens the difficulties associated with chemically driven QDs and thus have been extensively studied . Glasses embedded with PbS and PbSe QDs, for instance, can give broad and controlled emissions at an optical telecommunication window (1.2–1.7 μm) . However, for various applications such as solar cells, displays, light concentrators, bio‐imaging, and light‐emitting diodes, most studies have used chemically synthesized CdS, CdSe, or CdS 1− x Se x QDs.…”

Photoluminescence from PbS quantum dots and PbS/CdS core/shell quantum dots mixed with As2S3 glass

“…Absorption and photoluminescence spectra ( Fig. 1) verified that QDs provide the quantum confinement effect [13,14].…”