Photoelectric Properties Of Graphene And Sulfide Silver Composite Nanomaterials

Along with the sharp increase of population and the rapid development of socialeconomy, resources and energy are growing scarcity. Environmental protection is becomingmore and more attention. The new energy, energy saving technology, environmentalprotection technology development，the comprehensive and efficient utilization has becomevery necessary. Super capacitor with high power density, moderate energy density, especiallyin the field of electric vehicles has obvious advantages. Development with higher energydensity of super capacitor, and make it replace or partly replace the traditional secondarybattery has the very vital significance.The nonlinear optical materials are an important kind of materials in the futureoptoelectronic technology. Nonlinear optics has great influence on plasma physics, lasertechnology and nonlinear material physics, physical property research, solid state physics,astrophysics, spectroscopy, photochemical research and the analysis of the material structure.With the deep development of optical communication and optical information processing, theresearch progress on the nonlinear optical materials is also very fast. The research andapplication of nonlinear optical crystal put forward higher requirements of physical andchemical properties. Therefore, to design nanocomposites with good photoelectric propertiesis very important.In this paper, the nanocomposites containing graphene and Ag2S (G/Ag2S) weresynthesized by using a hydrothermal method. The capacitor performances and nonlinearoptical (NLO) properties of the G/Ag2S nanocomposites were investigated. The main contentsare as follows：1. The preparation and and characterization of G/Ag2S nanocompositesThe G/Ag2S nanocomposites were prepared by a hydrothermal method. The structureand morphology of the G/Ag2S nanocomposites were analyzed by X-ray diffraction (XRD),scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thesize of Ag2S nanoparticles was about130nm, which was uniformly covered the graphenesurfaces. Ag2S nanoparticles made the layer spacing increase and the porous structure form,leading to the coral structure linking each other with pills appear, which was useful for chemical reactions and embedded prolapse of charge, correspondingly improve the impedancematching properties of graphene.2. The capacitor performances of G/Ag2S nanocompositesFirstly, the G/Ag2S nanocomposites were mixed with conductive carbon and PTFE in aproportion. Then the mixture was coated on the foam nickel collector. After pressing anddrying, the electrodes were prepared. Finally, the electrochemical performances of theelectrodes in6M/L KOH electrolyte solution were measured using the Shanghai Chenhuachemical workstation. The cyclic voltammogram (CV) curve、constant current charge anddischarge curves and the electrical impedance spectra were obtained. From the CV curves, itcould be seen that the capacitor is redox pseudocapacitance which has ideal impedancespectroscopy. Within the voltage range of0.05~0.45V, the capacity was up to337.5F/gunder the conditions of2.5A/g constant-current charge. And the capacity was stable in280F/g after thousands of cycles under the conditions of5A/g constant-current charge.3. NLO properties of G/Ag2S/PMMA organic glassesThe G/Ag2S/PMMA organic glass organic glasses were prepared by a casting method.The UV-visible (UV-vis) absorption spectra of G/Ag2S/PMMA organic glasses were measuredusing a Shimadzu UV-2450spectrometer. The absorption peaks of the samples were in thewavelength range of300~400nm. Nonlinear absorption (NLA) properties of G/Ag2S/PMMAorganic glasses were investigated using an opening Z-scan technique. The experimentalresults showed that the G/Ag2S/PMMA organic glasses exhibited enhanced reverse saturableabsorption (RSA). The effective NLA coefficient βeffof the G/Ag2S/PMMA organic glasseswas in order of103cm/GW, which was approximately2.4,1.7and10.6times larger than thoseof (G/Ag2S)12/PMMA,(Ag2S)7.8/PMMAand G1.1/PMMA organic glasses.