溶胶凝胶旋涂法制备NiO薄膜及其电致变色性能

Preparation and Properties of NiO Films via Sol-gel Process and Spin-coating

本文利用sol-gel旋涂法在ITO玻璃衬底上成功制备了氧化镍(Ni O)薄膜。薄膜在550nm处的透过率为83.9%,直接禁带宽度为3.65 eV。XRD分析结果表明Ni O薄膜为立方晶相,沿(111),(200),(220)晶面生长,垂直于晶面(200)方向的晶粒直径尺寸大约为6.82 nm。循环伏安实验测试表明,Ni O薄膜在电化学反应过程中Ni2+不只经历了一次氧化反应,而是被氧化成更高价态的Ni3+,Ni4+价态,并通过计算得出薄膜在最强的阳极/阴极峰处的扩散系数为13.4×10-12cm2/s和2.29×10-12cm2/s,并且薄膜在550 nm处致色态与褪色态的透过率之差为36.5%,T/T为1.8。

NiO films have been successfully prepared via sol-gel process and spin-coating methods on ITO/glass substrates.The NiO films present optical transmitance of 83.9% at 550 nm and a direct energy band gap（E_g） of 3.65 eV.X-ray diffractometry（XRD） results show that the NiO films are cubic structure and growth along（111）,（200） and（220） planes,the average grain size along the normal of（200） is 6.82 nm.The cyclic voltammetry results reveal that the nickel in the film undergoes more than one cycle of oxidation/reduction process.The maximum anodic/cathodic diffusion coefficients are 13.4×10～（-12） cm～2/s and 2.29×10～（-12） cm～2/s.The transmittance ratio of the film between the coloured and blenched state is 36.5% at 550 nm with a photopic contrast ratio of 1.8.