双铁电复合材料的制备及其光电化学性能研究

通过模板法制备钒酸铋(BiVO₄)薄膜, 用溶胶-凝胶法制备铁电材料铁酸铋(BiFeO₃)并对BiVO₄进行修饰, 以半导体复合的方式提高BiVO₄的光电化学性能。电化学测试结果表明, 经BiFeO₃修饰后, BiVO₄薄膜的光电化学性能有所提高, 其中经BiFeO₃旋涂5次后的BiVO₄薄膜具有最优的光电化学性能, 光电流密度达到0.72 mA·cm^-2, 较未修饰样品提高了67.4%。利用外场极化调节能带弯曲可以显著地提高BiVO₄/nBiFeO₃铁电复合物的光电化学性能, 复合物经正极化20 V电压处理后的光电流密度最高为0.91 mA·cm^-2, 比BiVO₄薄膜提升了1倍以上, 具有良好的光电化学性能。BiFeO₃与BiVO₄复合后有利于形成异质结, 促进光生电子、光生空穴的产生与分离, 并且外场极化调节能带弯曲使光生电荷加速转移, 是铁电复合物光电化学性能提高的主要原因。

Preparation and Photoelectrochemical Property of the Dual-ferroelectric Composited Material

BiVO₄ film was synthesized via template method, the ferroelectric material BiFeO₃ was prepared by Sol-Gel method to modify BiVO₄. By means of dual-ferroelectric semiconductor composition, the photochemical properties of BiVO₄ was greatly improved. The electrochemical test results show that the superior photoelectrochemical properties of BiVO₄ film are achieved after spin-coating with BiFeO₃ for 5 times. It owns an optimal photocurrent density of 0.72 mA·cm^-2, which is 67.4% higher than that of pure BiVO₄. The energy band bending regulation via electric field polarization could further boost the photoelectrochemical property of BiVO₄/nBiFeO₃ ferroelectric composite. The highest photocurrent density of the composite after polarization at 20 V reaches 0.91 mA·cm^-2, which is more than twice of pure BiVO₄ film. The combination of BiFeO₃ and BiVO₄ is favorable for forming heterojuncting, generating and separating of photogenic electrons and holes. The electric field polarization regulating band bending accelerates the photogenic charge transfer, which is the main reason for the improved photoelectrochemical properties of ferroelectric composite.