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Lead selenide (PbSe) quantum dots (QDs) doped with Sr 2 + were precipitated in silicate glasses. The absorption and photoluminescence (PL) bands of the glasses blue-shifted as SrO concentration increased. These changes resulted mainly because Sr incorporation increased the band gap of PbSe nanocrystals. After heat treatment at 520 °C for 10 h, mean QD diameters were similar before and after the addition of SrO: ~ 7.2 nm with 0% SrO and ~ 6.9 nm with 10 mol% SrO. However, these two glasses show the absorption bands at 1743 nm and 1246 nm, and PL bands at 1803 and 1370 nm, respectively. These large shifts are due to the increase in the band gap through the formation of Pb 1 − x Sr x Se mixed-type QDs. One typical chemical composition of QDs formed in a glass with 10 mol% SrO after heat treatment at 520 °C for 10 h is Pb 0.89 Sr 0.11 Se with a band gap of ~ 0.58 eV. [ABSTRACT FROM AUTHOR]

Infrared photoluminescence (PL) properties of Sn-modified PbSe quantum dots (QDs) in silicate glass were investigated. The QDs' sizes were controlled by changing the heat treatment temperatures. The longest absorption peak from Sn-modified PbSe QDs was centered at 2590 nm, and the PL band extended to 2650 nm. X-ray diffraction peaks indicated that the PbSe QDs formed in the glass matrix although low Sn content resulted in no obvious difference between PbSe QDs and Sn-modified PbSe QDs. Sn was found in QDs that proves the incorporation of Sn into PbSe QDs. The proposed composition of the Sn-modified PbSe QDs was Pb 0.92 Sn 0.08 Se with a band gap of ~ 0.13 eV; the small amount of Sn changed the energy structure of QDs, narrowed the band-gap, and increased the PL emission wavelength. [ABSTRACT FROM AUTHOR]

Lead selenide quantum dots (QDs) were precipitated in germanosilicate glasses to investigate the effect of GeO 2 content on the precipitation and optical properties. The absorption and photoluminescence (PL) bands red-shifted strongly as GeO 2 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 GeO 2 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 GeO 2 concentration, and is the main reason for these red-shifts. [ABSTRACT FROM AUTHOR]

• Ternary Pb 1−x Sr x Se quantum dots were prepared in the silicate glass. • Pb2+ concentration determine the density of Pb 1−x Sr x Se QDs in glassy matrix. • The higher Se/Pb ratio facilitates the formation of large-size quantum dots. Lead selenide quantum dots (QDs) were precipitated in silicate glasses with different contents of SrO. As the concentration of SrO increased from 0 to 10 mol%, the absorption peaks of the glasses with the heat treatment at 520 °C for 10 h blue-shifted from 1535 nm to 947 nm, and their photoluminescence (PL) peaks from 1578 nm to 1184 nm. The blue-shifts resulted from the incorporation of Sr2+ ions into PbSe crystal lattice, which leads to the increase of the bandgap of PbSe QDs. Meanwhile, the optical properties of Sr2+-doped PbSe QDs were investigated by changing the precursor concentrations of Pb and Se. It is found that the concentration of Sr2+-doped PbSe QDs in the glassy matrix is mainly determined by the contents of the Pb precursor. To form larger size QDs requires higher oversaturation of Se to Pb elements, which promoted the further growth of QDs. [ABSTRACT FROM AUTHOR]