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钙钛矿材料可以分为ABO3氧化物和ABX3 (X = Cl, Br或I)卤化物两大类, 它们都具有丰富的物理性质和优异的光电性能, 比如铁电性和光催化性能. 本文介绍了BiFeO3和MAPbI3等铁电半导体光催化材料和异质结的制备方法, 总结了它们在光电催化方面的研究进展. 目前研究者已经针对氧化物光催化材料做了各种研究, 包括: 降低吸光层铁电材料的带隙, 制备铁电/窄带半导体吸光层异质结, 制备比表面积很大的纳米片、纳米棒或者其他纳米结构, 以便吸收更多可见光; 让铁电极化及其退极化场垂直于光催化工作电极表面, 通过铁电/半导体异质结能带弯曲提供内电场, 通过外电场进行光电催化, 从而通过内、外电场高效分离光生-电子空穴对; 通过光催化或者光电催化降解染料、分解水制氢、将CO2转换为燃料; 通过铁电、热释电和压电协同效应提高催化效应和能量转换效率. MAPbI3等卤素钙钛矿具有优异的半导体性质, 其铁电性可能是引起超长的少数载流子寿命和载流子扩散长度的原因. 通过优化光催化多层膜结构并添加防止电解液渗透的封装层可以避免MAPbI3被电解液分解, 从而制备了具有很高能量转换效率的光电催化结构. 最后, 我们分析和比较了这些钙钛矿铁电半导体在光电催化领域面临的挑战, 并展望了其应用前景.There are two types of perovskites, i.e. ABO3-type oxides and ABX3-type (X = F, Cl, Br and I) halides. Both of them exhibit rich physical properties and excellent photoelectric properties, such as ferroelectric and photocatalytic properties. In this paper we introduce the methods of preparing the ferroelectric semiconductors (i.e. BiFeO3 and
MAPbI3) and their heterogeneous junctions for photocatalytic applications, and summarizes the research progress and applications of photocatalytic devices. Various researches about oxide photocatalytic devices have been carried out. At first, several methods have been developed to absorb more visible light, such as reducing the band gap of ferroelectric materials, preparing junction composed of ferroelectric layer and light absorption layer with narrow-bandgap semiconductor, and growing nanosheet, nanorods or other nanostructures with large specific surface areas. Second, some electric fields are introduced to effectively separate light activated electron-holes pairs. In addition to the external electric field, an inner electric field can be introduced through the ferroelectric polarization perpendicular to the surface and/or the energy band bending at the ferroelectric/semiconductor interface. Thirdly, the degradation of dyes, the decomposition of water into hydrogen and the conversion of CO2 into fuel have been realized in many photocatalytic or photoelectrocatalytic devices. Fourthly, the synergies of ferroelectric, pyroelectric and piezoelectric effects can largely increase the photocatalytic efficiency and the energy conversion efficiency. Furthermore, MAPbI3 and other halogen perovskites show excellent semiconductor properties, such as the long carrier diffusion length and long minority carrier lifetime which may originate from ferroelectric dipoles. The MAPbI3 can be applied to photocatalytic devices with a high energy conversion efficiency by optimizing the photocatalytic multi-layer structure and adding a package layer that prevents electrolyte for decomposing the MAPbI3. Finally, we analyze the challenges of the high-efficiency photocatalytic devices and look forward to their application prospects. -
Keywords:
- photocatalytic /
- ferroelectric polarization /
- electron-hole pairs /
- energy conversion efficiency
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中国物理学会期刊
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