Strong confinement of PbSe nanocrystals in phosphate glass

Lead selenide quantum dots (QDs) are grown in a novel mixed sodium-lithium phosphate glass. Samples with sharp absorption transition, at 1.48 eV in the near infrared region, and QDs size of 1.5 nm have been prepared. The size of QDs has been calculated from X-ray diffraction and absorption analysis data. The observed high shift in the absorption spectra of PbSe QDs and its size confirm the strong confinement regime of the system. A third harmonic optical phonon of PbSe at 419 cm−1 has been observed in infrared spectra. Transformations in infrared spectra due to growth of nanoparticles have been studied and explained in terms of Pb-withdrawn from the host glass matrix.