形貌可控及光学吸收性能可调的钙钛矿型SrTiO3纳米结构的原位生长

钙钛矿相SrTiO₃在太阳能电池、光催化、燃料电池, 超导等领域均有广泛应用, 这些应用均与其晶体质量、形貌、暴露晶面和光学吸收等特性息息相关。本文通过微弧氧化-水热两步法原位制备了两种典型形貌的SrTiO₃纳米晶。结果表明, 随着微弧氧化电解液锶源浓度的降低, SrTiO₃形貌从立方块状转变为超薄片状。进一步分析表明, 所得的SrTiO₃立方块和Sr_1-δTiO₃纳米片均为结晶质量良好的单晶体, 通过分析两种形貌样品的紫外-可见漫反射光谱, 发现Sr_1-δTiO₃纳米片相对于SrTiO₃立方块, 具有明显的尺寸效应诱导的光学吸收蓝移特性。最后, 本研究提出了SrTiO₃的原位生长及形貌演变机制。

In-situ Synthesis of Perovskite SrTiO3 Nanostructures with Modified Morphology and Tunable Optical Absorption Property

As a perovskite family member, SrTiO₃ shows significant applications in the fields of solar cells, photocatalysis, fuel cells and superconducting as a dependence of its crystallinity, morphology, crystal facet and optical properties. In this work, we reported an in-situ synthetic approach of SrTiO₃ nanostructures with modified morphology and tunable optical absorption properties based on conventional plasma electrolytic oxidation (PEO) associated with hydrothermal method. The morphology of SrTiO₃ nanostructures can be selectively modified from microcubes with smooth facets to ultrathin nanosheets by controlling the concentration of Sr source during PEO process. It is found that both SrTiO₃ microcubes and Sr_1-δTiO₃ nanosheets are well-crystallized single crystals. UV-Vis diffuse reactance spectrum (DRS) measurement reveals that Sr_1-δTiO₃ nanosheets with thin thickness show obvious blue-shift of absorption edge in comparison with SrTiO₃ microcubes due to the size effect. Finally, the morphology evolution and nucleation mechanism of SrTiO₃ nanostructures in-situ grown on PEO film is discussed.