【作者】 杨立荣；

【导师】 靳正国；

【作者基本信息】 天津大学 ， 材料学， 2005， 博士

【摘要】 ZnO是n-型宽禁带半导体材料,由于其具有高的光吸收和良好的电子输运性能,近年来被用作纳米晶太阳能电池的光阳极材料。这种电极要求薄膜具有多孔结构和较大的表面积,因此选择合适的ZnO薄膜制备方法是制备高性能纳米晶多孔膜的关键。课题采用无机盐络合溶胶凝胶法、电化学沉积法以及PEG辅助的溶胶凝胶法制备了多孔ZnO薄膜。研究了制备过程对薄膜显微结构和性能的影响,并对多孔的形成机理进行了初步探索。采用无机盐络合溶胶凝胶法制备研究表明:柠檬酸与Zn²⁺可形成稳定的络合羧酸盐,制得的ZnO薄膜呈多孔状,孔径分布主要在2.02～4.97nm范围。薄膜的BET比表面积是27.6 m²/g。在可见光范围内光透射率超过90%,光学带隙宽度为3.25 eV。SDS参与的电沉积研究得出,Zn²⁺浓度为0.02M,SDS含量为5wt%,沉积电压为-1.0v时得到的ZnO薄膜表面由层状晶组成,且相互搭结形成多孔状。SDS吸附在电极表面与带正电的Zn²⁺形成表面活性剂-无机聚集体导致薄膜多孔的形成。在可见光范围内,薄膜的光透过率在75%以上,光学带隙宽度为3.6eV。在CTAB参与的电沉积中,由1wt%CTAB的0.02M Zn（NO₃）₂电解液,沉积电压-1.0V时得到的薄膜为卷曲的薄片状ZnO组成,表面呈多孔结构。多孔形貌与CTAB在电极表面的吸附作用相关。在可见光范围内,薄膜的光透过率随波长的减少而降低,且沉积电压越大,光透射率越小。由PEG辅助的溶胶凝胶法制备的ZnO薄膜呈多孔状,溶胶粒子与PEG形成PEG-O-Zn结合体。溶胶70℃水浴处理有利于大孔结构的形成,孔径在200-400nm,大孔的形成是体系分相形成的。未水浴处理的溶胶薄膜也呈多孔结构,孔径大约在40-100nm,此时PEG起到了连接颗粒和包裹颗粒的作用。更多还原

【Abstract】 ZnO is n-type wide band-gap semiconductor materials. Because of its highabsorption for light and good electron transportation, ZnO is used asphoto-electrodes of nanocrystalline solar cell which should have porousstructure and larger surface area. The key that synthesizes good property,nanocrstalline and porous ZnO films is the preparing method.Porous ZnO films were synthesized respectively by using inorganicchelating sol-gel method, electrochemical deposition and PEG-assisted sol-gelmethod. The effects of processing conditions on the microstructure andproperties of the ZnO films were studied and the pore forming mechanism ofeach method was discussed fundamentally.The stable chelate complex of citric acid and Zn²⁺ was synthesized byinorganic chelating sol-gel method. The surface of ZnO films was porous andthe pore distribution was mainly in the range of 2.02～4.97nm. The surface areaof the ZnO film was 27.6m²/g. The transmittance was above 90% in visibleregion and the band gap was 3.25eV.The ZnO film deposited from 0.02M aqueous solution of Zn（NO₃）₂·6H2Omixed with 5wt%SDS was composed of lamellar crystalline and porousstructure, which indicated that the anionic headgroups of SDS cooperativelyinteract with Zn²⁺ under our deposition condition on the electrode. Thetransmittance was above 75% in visible region and the band gap was 3.6eV.The ZnO film deposited from 0.02M aqueous solution of Zn（NO₃）₂·6H₂Omixed with 1wt%CTAB was composed of curl flake crystalline and porous,which result from the sorption of CTAB on the electrode. The transmittance ofZnO films decreased with reducing wavelength, and the more the depositionvoltage was, the less the transmittance was.The ZnO films synthesized by PEG-assisted sol-gel method were porous andthe PEG-O-Zn complex was formed between PEG and sol particle. The solbathed at 70℃ was propitious to the formation of big pores and the pore sizewas about 200-400nm, which result from phase separation in this system.However, the less pore could be formed without sol bath and the pore size wasabout 40-100nm, which resulted from the linking and wrapping colloid action ofPEG..更多还原