Germanosilicate glasses containing PbSe quantum dots for mid-infrared luminescence

• Large size PbSe QDs (~ 12.5 nm) were formed by adding GeO2 in silicate glasses.
• The absorption bands and PL bands red-shifted as GeO2 concentration increased.
• Mid-infrared luminescence at ~ 2.6 μm was realized from PbSe QDs in a glass.

Lead selenide quantum dots (QDs) were precipitated in germanosilicate glasses to investigate the effect of GeO2 content on the precipitation and optical properties. The absorption and photoluminescence (PL) bands red-shifted strongly as GeO2 concentration increased. After heat-treatment at 470 °C for 10 h, the first excitonic absorption bands red-shifted from 801 nm to 2593 nm as GeO2 content increased from 0 to 40 mol%, and thus PL at 2619 nm was achieved. The corresponding average QD diameters were 2.48–12.54 nm. The precipitation of large PbSe QDs resulted from the enhancement of diffusion with the increase of GeO2 concentration, and is the main reason for these red-shifts.