材料期刊网

二氧化钛是一种无毒、廉价、稳定的半导体材料,被广泛用作光电化学太阳能电池的电极材料,适当掺杂可以增强其光电性能.以钛酸丁酯和四正丁氧基锗烷为主要原料,采用溶胶-凝胶提拉涂膜法制备了Ge掺杂的TiO_2薄膜.通过X射线衍射、扫描电镜、紫外-可见吸收光谱、电流-电压曲线等测试手段研究了薄膜的结晶性能、微观结构和光电性能随Ge掺杂量的变化规律.结果表明,Ge掺杂量x=0.10时,形成Ti_(1-x)Ge_xO_2固溶体,x=0.15时,形成非晶态.掺锗后薄膜表面颗粒密度增大,薄膜比较致密.随着Ge掺杂量的增加,吸收光谱吸收边蓝移,光电化学性能也得到一定提高.在Ge掺杂量为0.05时,光电流达到最大值17A/m~2.同时,研究了锗掺杂对光电流的影响.

Photoelectrochemical (PEC) solar cells have attracted considerable attention as one of the most effective ways to utilize solar energy.As a cheap and stable semiconductor material,TiO_2 has been frequently used in the PEC solar cells.Doping is one of the most effective ways to enhance the photoelectrochemical properties of TiO_2 thin film electrodes.So far,many efforts have been made to synthesize doped TiO_2 photoelectric films to develop the photoelectrochemical performance.In this study,germanium doped TiO_2 thin films have been synthesized by sol-gel dip-coating method using butyl titanate (Ti(OC_4H_9)_4) and tetra-n-butoxygermane (Ge[O(CH_2)_3CH_3]_4) as the titania and germania precursors,respectively.X-ray powder diffraction (XRD),scanning electron microscope (SEM) attached with energy dispersive X-ray spectroscopy (EDS),optical absorption spectra,and current-potential (I-V) curves have been studied for the prepared Ge-doped TiO2 thin films.The results revealed that Ti1-xGexO2 solid solution formed when x=0.10,while the film exists amorphous when x=0.15.The anatase crystal structure was destroyed gradually with increasing germanium amount.Doping germanium reduced the grain size.The surface morphology of Ge-doped films showed higher particle density than that of pure TiO_2,hence increasing the active site numbers and improving the photoelectrochemical properties.The increase of Ge amount caused a gradual blue shift of optical absorption edge in UV-Vis absorption spectra.The photocurrent was enhanced with proper doping amount,owing to more active sites and comparatively better crystallinity.The maximum value of photocurrent reached 17A/m~2 when germanium amount was 0.05.The mechanism of effects of Ge-doping on the photocurrent of TiO_2 thin film electrodes was also investigated.