ZnIn_2S_4薄膜喷雾热分解制备及其光电化学性质

Preparation of ZnIn_2S_4 Thin Film by Spray Pyrolysis and Its Photoelectrochemical Characteristic

以ZnCl2、InCl3.4 H2O和(NH2)2CS为原料,采用喷雾热分解方法在ITO玻璃上制备了高质量的ZnIn2S4薄膜,使用X射线衍射仪、扫描电镜和分光光度计对制备的薄膜进行了结构、形貌和光学性质的表征,利用基于密度泛函理论的平面波赝势方法对制备的立方相ZnIn2S4进行了能带结构计算,并采用锁相放大技术研究了ZnIn2S4电极的光电流作用谱图.结果表明:使用喷雾热分解方法能够制备结晶完好、无针孔的ZnIn2S4薄膜,制得的薄膜呈立方相,在可见光区(λ>420nm)有很好的光吸收;薄膜为间接带隙半导体,价带最高轨道由S3p+In5p构成,导带最低轨道由S3p+In5s轨道构成,作为光电极使用可有很好的光电化学响应,在0.1 mol/L Na2SO3和0.1mol/L Na2S的混合电解质溶液中,0.3 V电极电势下400 nm处的光电转换效率(IPCE)达到了30%以上.

ZnIn2S4 thin films were prepared on ITO conductive glass by spray pyrolysis from a mixed aqueous solution of ZnCl2, InCl3 · 4H2O and （NH2）2CS. Some properties of the deposited film, such as structure, morphology and optical characteristics, were characterized by XRD, SEM, and UV-vis spectrum. Moreover, the band structure and density of states were evaluated with the plane wave pseudopotential method based on density functional theory. The photocurrent action spectrum was investigated via lock-in technique. It is found that high crystallinity and pinhole free cubic Znln2S4 film with fine adhesion to ITO substrate can be prepared by spray py- rolysis. The deposited film is endowed with a cubic spinel structure with good absorption in visible light. The cubic ZnIn2S4 is a indirect gap semiconductor, whose valence band maximum（HOMO） mainly consists of S3p＋In5p orbitals, and the conduction band minimum（LUMO） consists of S3p＋In5s orbitals. As a photoanode, the deposited film exhibits a good photoresponse. In 0. 1 mol/L Na2SO3＋0. 1 mol/L Na2S mixed solution, the IPCE achieves over 30% at a potential of 0.3 V vs. SCE（Saturated Calomel Electrode） at 400 nm irradiation wavelength.