Synthesis And Analysis Of PbS And PbSc Quantum Dots In The Phospha Teglass

The PbS and PbSe semiconductor nanocrystal were synthesized in thephosphate glass with different heat treatment conditions by using a meltingmethod. The PbS and PbSe nanocrystals generated in the glass wereverified by a x-ray diffraction (XRD), a x-ray fluorescence spectroscopy(XRF), an energy dispersive x-ray spectroscopy (EDX), a high-resolutiontransmission-electron-microscopy (HRTEM) and UV-VIS-NIRspectrophotometer. A detailed analysis of the experimental results is given,and then the problems which effecting the experiment results and thesolving ways in the synthesis are summarized finally, one of which is howto control the annealing temperature. The results show that: (1) The PbSsemiconductor nanocrystals are synthesized in P₂O₅-Na₂CO₃-ZnOAlF₃·3H₂O-CaCO₃-SiO₂ phosphate glass system. The size is about 60-100nm with a broad size distribution; (2) The PbSe nanocrystals aresynthesized in phosphate glass P₂O₅-Na₂CO₃-AlF₃·3H₂O-Al₂O₃ system, with a high concentration, an evenly distribution, and in size of 5-10nm; (3)The annealing is necessary in the synthesis process, and the annealingtemperature and cooling rate must be controlled carefully. To avoid theinner stress generated in the melting process and obtain crack-free glasssamples, the annealing temperature should be controlled in ⁵0℃less thanglass transition temperature; (4) the added quantity of lead oxide(PbO) andZinc sulfur (ZnS) must be appropriate. If it is too low, the quantum dotswill be not formed in the glass, whereas, the phosphate glass will becomeopaque; (5) Titanium dioxide (TiO₂) as a nucleating agent is added insilicate glass synthesis process, it can not be added in phosphate glassesbecause it will cause the opaque in the phosphate for a high meltingtempreture (1830～1850℃) of TiO₂.