PbSe Quantum Dot-Doped Silicate Fiber Materials By Melting Method

In recent years, study on semiconductor nanocrystal materials (quantum dots, QDs) develops rapidly in the world. The QDs including in II-VI, III-IV, and IV-VI elements attract much attention due to their unique optical performance of size dependence. Recent evidence shows that the IV-VI QD doped glasses have photoluminescence (PL). For example, PbS QD in diameter of 5~10 nm has strong PL emission located in 1200~2000 nm that is desirable for near-infrared communication band. However, PbSe QD doped glass, as a novel optical fiber material, has not been investigated in details.This dissertation focuses on the PbSe QD doped glass.First, the PbSe QD doped silicate glass is prepared successfully by using a melting method. The size, distribution, absorption and PL spectra of PbSe QDs in the glass are characterized by using a x-ray diffractometer, transmission electron microscope (TEM), UV-Visible-NIR spectroph- otometer, fluorescence spectrometer and x-ray fluorescence spectrometer, respectively. The results indicate that the obtained PbSe QDs in the glass have a wide size distribution around (5~13)±2 nm, with a doped volume ratio of (0.5~1)%. The sze of the QDs in the glass can be tuned by controlling the heat treatment temperature and time. The QD concentration can be increased by adding ZnO into the glass batch and using a two-step heat treatment method. The spectrum measurement shows that the PbSe QD doped glass has enhanced PL emission, widened FWHM (245~808nm), and desirable wavelength of 1546~2757nm that locates C-L waveband.Then, temporal stability of PL spectra in PbSe QD doped glass is investigated by observing and comparing PL spectra for a long time (5 months). The results indicate that the PbSe QD doped glass prepared in this study has a desirable temporal stability, and the PL spectra of the QD doped glass are not changes with time.Finally, PbSe QD doped fiber is fabricated by using a melt-drawing method. The structure, mechanical property, QD size and PL spectrum of the fiber are observed and analyzed by the optical microscope, TEM and the optical spectrum analyzer. The results show that the fiber has a uniformity diameter in 60~120μm, smooth surface and circular cross section. Its mechanical property comes near that of ordinary silica fibers.Based on the above study, a conclusion can be made that the PbSe QD doped silicate glass is a novel fiber material with strong PL emission, wide bandwidth and stable performance. It can be a potential competitor for a new generation fiber amplifier of communication.