Synthesis Of PbS,PbSe,PbS_xSe_1-x Quantum Dots And Their Optical Linmiting Properties

Semiconductor nanocrystals have attracted great research interest due to their unique optical and electrical properties. These properties include controllable optical absoption properties, large extinction coefficient, and extended photostability, which underlie extensive application in photoelectric device. PbS and PbSe are important Ⅳ-Ⅵ rock salt structure semiconductor materials with narrow band gap energy (PbS:0.41eV, PbSe:0.28eV) and large exciton Bohr radius (PbS:18nm, PbSe:46nm), whcih are useful in novel nanodevices such as light-emitting diodes, single electron transistors, field-effect thin-thim transistors, solar cell and thermoelectric material.The main finding of this thesis includes:1. We prepared PbS nanoparticles modified with different ligands. We studied the effects of temperature and reaction time on quantem dots’s size and morphology modified with oleylamine, oleic acid,1-hexadecanamine, parabromoaniline.2. We proposed a novel method for preparation of PbSe and obtained cubic and spherical PbSe nanocrystal modified with oleylamine. We also obtained high quality cubic and spherical PbSe nanocrystal under octadecene. We explored the effects of temperature and the amount of oleylamine on quantum dots’size and morphology.3. We fabricated PbSxSe1-x ternary nanoparticles on the basis of PbS and PbSe, and studied their structure and composition. We then studied near infrared absorption and optical limiting properties of ternary PbSxSe1-x quantem dots.