Study On Preparation And Surface Photovoltage Characters Of CdTe Nanocrystal

In this article, CdTe nanocrystallines（NCs） were prepared by aqueous method with,thioglycolic acid （TGA）, 3-sulphur-1,2-propylene glycol （TG） and 3-Mercap- topropionicacid （MPA） in aqueous solution. And through changing a series of experimentalconditions in aqueous solution optimized the preparation of CdTe QDs is proposed andthe orthogonal experiment table to photovoltaic response as the index, the optimumtechnological conditions for Cd/Te/TG molar rate is 1:0.2:2.4, PH value is 9, the reactiontime is 6 h, Cd²⁺concentration 10 mmol/L. The results show that the synthesis CdTe QDswith single scattered characteristics, particle size is concentrated relatively, the averageparticle size is about 4 nm, and it can be controlled by the time of backflow.The characterization of samples were taken by using transmission electronmicroscope, CdTe QDs are microstructure of approximatively sphere. Using X-raydiffraction indicated that partial sulfydryl happen sulfydryl, and make a small amount ofS participation in Cd ions coordination effect. By IR spectra and EDS energy spectrumconfirmed that a small amount of S of sulfydryl participation in Cd²⁺ions coordination,formed as a kind of nuclear shell structure. Using Raman further study the core-shellstructure. Using surface voltage spectrum （SPS） and the electric field induced surfacephotovoltaic spectroscopy （EFISPS） analysis surface electronic structure of samplephoton-generated carrier behavior. And structure models of CdTe doped different sulfurcontents were built and calculated its phonon spectra and phonon state density by theMaterials Studio, the results provide a theoretical foundation and basis for the experiment.Experimental and simulation results show that: With the increasing in sulfur content ofcadmium telluride nanocrystals become more stable. At the same time, nanocrystallineCdTe samples show obviously n type photovoltaic surface characteristics.