Preparation And Characterization Of Cadmium Sulfide And Lead Sulfide Nanomaterials

Cadmium sulfide(CdS),an intrinsic semiconductor inâ…¡-â…¥group with a direct transition band structure,is widely used in the field of solar energy conversion, nonlinear optics,actinochemistry battery and photo catalysis.Lead sulfide(PbS)is an important semiconductor material with a small bandgap(0.41 eV)and large exciton Bohr radius(18 nm).It is promising in the applications in the fields of nonlinear optics,IR detectors,displaying devices,light emitting diode and solar cell.Thus,it is of interest to carry out studies on PbS and CdS nanomaterials.Template method,sonochemistry method,surfactant assisted chemical synthesis method were used to prepare CdS,PbS and CdS/PbS composite materials.Some test methods such as XRD,TEM,absorption spectra and PL were used to analyze these nanoparticles.CdS hollow sphere-tubular nano-structures,PbS hollow sphere nano-structures and CdS/PbS composite nano-materials were prepared via the source template-interface reaction route.The result of XRD analysis showed that the crystal structures of CdS were hexagonal;the result of TEM observation showed that the CdS samples were hollow sphere-tubular nanostructures;the result of optical absorbance measurement presented that exciton absorption peak of CdS appear at 407 nm;the result of PL measurement showed that fluorescence emission peak of CdS appeared at 470 nm.The crystal structures of PbS were face-centered cubic,the PbS samples were nano-hollow spheres,with exciton absorption peak at 1906 nm and fluorescence emission peaks at 1328 nm and 1516 nm.CdS and PbS of the CdS/PbS composite nano-materials were separately of the structures of hexagonal and face-centered cubic,with exciton absorption peaks at 432 nm,1692 nm and 1735 nm and fluorescence emission peaks at 472 nm,495 nm and 1610 nm.Nano-cubic CdS,PbS,and CdS/PbS composite nanoparticles were prepared via sonochemistry method.The result of XRD analysis showed that the crystal structure of CdS was hexagonal;the result of TEM observation showed that cubic structure; the result of optical absorbance measurement presented that exciton absorption peak of CdS appeared at 409 nm;the result of PL measurement showed that fluorescence emission peak of CdS appeared at 525 nm.The crystal structure of PbS was face-centered cubic,with exciton absorption peak at 1728 nm,fluorescence emission peak of PbS appeared at 1641 nm.CdS and PbS of the CdS/PbS composite nano-materials were separately of the structures of hexagonal and face-centered cubic, with exciton absorption peaks at 429 nm,1411 nm and 1908 nm and fluorescence emission peaks at 515 nm,546 nm,1728 nm and 1738 nm. CdS nanoparticles were prepared adding anionic surfactant AOT,Na(PO₃)₆ as stabilizer respectively.The result of XRD analysis showed that the crystal structure of CdS was hexagonal.The result of TEM observation showed that the average particle size of CdS nanoparticles was 5～8 nm;the result of optical absorbance measurement presents that exciton absorption peak of CdS nanoparticles appeared at 401 nm;the result of PL measurement showed that fluorescence emission peak of CdS nanoparticles appear at 516 nm.The average particle size of CdS stabilized with Na(PO₃)₆ was 2～3 nm,with exciton absorption peak at 303 nm and fluorescence emission peak at 336 nm.PbS nano-rods were prepared by using surfactant PVP as stabilizer.The result of XRD analysis showed that the crystal structure of PbS was face-centered cubic.The result of TEM observation showed that the diameter and the length of the PbS nanorods was about 500 nm and up to 11μm.The result of optical absorbance measurement presented that exciton absorption peak of PbS appeared at 1731 nm. The result of PL measurement showed that fluorescence emission peak of PbS appeared at 1516 nm.PbS quantum dots,CdS/PbS hybrid quantum dots were prepared by using anionic surfactant thioglycollate as stabilizer.The result of TEM observation showed that the average particle size of PbS quantum dots was only 1～2 nm;the average particle size of CdS/PbS hybrid quantum dots was only 2～3 nm.Through alternate static electric self-assembly method,nanoparticle/Alician Blue 8GX(AB)thin films were plated on ITO conductive glass,then assembled photocell. The linear voltammetry curve presented the instantaneous current efficiency of the photocell with light are about 1.5 times,5 times,2 times higher than that without light. Among them,the PbS quantum dots stabilized with thioglycollate/AB thin films photocell was more significant photoelectric effect in the infrared spectral region.