Influence of Intermediate ZnO on the Crystallization of PbSe Quantum Dots in Silicate Glasses

Glasses containing PbSe quantum dots have important prospective applications in the area of near infrared optoelectronic devices. ZnO plays an important but complicated role in the preparation of quantum dot glass. We gave reasonable elaborations on the color changes of the as-prepared and annealed glasses containing PbSe quantum dots. The as-prepared glasses presenting nearly black to transparent straw-yellow colors with rising ZnO content can be understood in terms of the conversion between PbSe and ZnSe; the colors of all annealed glasses turning very black can be well explained through thermodynamic calculations with the Gibbs-Helmho1tz equation. Next, according to the results of X-ray diffraction, transmission electron microscopy and optical measurements, the sample with an introduction of 9.4 wt.% ZnO possesses a maximum degree of crystallization and the best optical properties among all samples, which suggests the host glass with addition of 9.4 +/- 1 wt.% ZnO is optimum for crystallization of PbSe quantum dots. Finally, we employed classical nucleation theory to quantitatively calculate the nucleation rates and growth rates of PbSe quantum dots, and found that with the growing ZnO content in host glass, the nucleation rate decreases, whereas the growth rate of PbSe quantum dot increases gradually.