Formation of Photoluminescent Lead Bromide Nanoparticles on Aluminoborosilicate Glass

Abstract

A multicomponent aluminoborosilicate photoluminescent glass was synthesized by introducing Pb(II) and NaBr in its composition. The room-temperature photoluminescence is due to the existence of 4 nm nanocrystals, shown using TEM imaging and XRD analysis, which are assigned to PbBr 2 nanocrystals. The glasses display a broad emission band with a peak at 2.85 eV by exciting at 3.35 eV, with an anisotropy equal to 0.19 at room temperature. At 77 K, the emission intensity increases 1 order of magnitude and a vibronic structure appears, indicating an electron−phonon coupling with the glass matrix. Time-resolved luminescence measurements of these nanocrystals reveal mixed-order kinetics, with second-order recombination of self-trapped electron centers and a first-order temperature-dependent nonradiative rate constant connected with pathways due to confinement of self-trapped centers.

Photoluminescent Nanocrystals in a Multicomponent Aluminoborosilicate Glass

“…The synthesis protocol is similar to the one described elsewhere. 33 The main difference is the presence of different halogens (X), such as F − , Cl − , Br − , and I − , with a molar ratio (r) of X/Pb = 1.33 in the glass composition. In the case of I − , a glass with a different ratio was also produced, I/Pb = 3.…”

“…In the case of I − , a glass with a different ratio was also produced, I/Pb = 3. The full synthesis protocol is available in the previous article 33 and in the Supporting Information.…”

“…Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), microenergy dispersive X-ray fluorescence (μ-EDXRF), and powder X-ray diffraction (XRD) measurements were obtained with equipment and methods described elsewhere. 33 In the case of the sample doped with iodine, a JEOL JEM-2200FS, 200 kV, Oxford INCA Energy TEM 250, was also used for TEM measurements.…”

“…Reagent grade SiO 2 (p.a., Fluka), B 2 O 3 (99%, Acros Organics), Al 2 O 3 (p.a., Merk), Pb 3 O 4 (Panreac), BaO (>98%, Aldrich), Li 2 CO 3 (p.a., Fluka), Na 2 CO 3 (p.a., Riedel de Haen), K 2 CO 3 (p.a., Panreak), NaF (Merk), NaCl (p.a., Panreak), NaBr (99.5%, Merck), and NaI (Merk) were used as raw materials. The full synthesis protocol is available in the previous article and in the Supporting Information.…”

“…UV/vis absorbance spectra were recorded on a Varian Cary-5000 UV/vis/NIR spectrophotometer over the 300–1800 nm wavelength range with a 1 nm resolution. Luminescence spectra, time-resolved luminescence spectra, and single photon counting (SPC) measurements were described elsewhere . Fluorescence quantum yields were measured using an F-3018 Integrating Sphere accessory (Horiba Jobin Yvon).…”