Bi@MoS2对TiO2纳米片阵列晶面的选择性修饰及光电性能研究

Photo-generated carrier transfer and separation among different crystal faces can be promoted by the means of optimizing the percentage of exposed crystal facets. The selective decoration of heterostructure on the facets will facilitate the spatial separation of carrier and enhance photoelectronic performance. In this work, vertically oriented single-crystalline TiO2 nanosheet arrays were grown on the conductive glass in-situ by hydrothermal method. The as-deposited TiO2 nanosheet arrays are used as the substrates, the {001} crystal faces are decorated with MoS2 nanosheet, forming a 2D-2D structure, and {001}/{101} crystal faces are decorated with Bi particles selectively. The effect of the selective decoration of different crystal facets, morphology and percentage of high energy facets on photoelectronic properties are studied in detail. In terms of the band structure of {001}/{101} facets and Bi, MoS2, synergistic effects of charge transfer and interface state on photoelectronic enhancement are explored. By construct Bi-MoS2-TiO2 nanosheet arrays that make use of charge transfer of MoS2-TiO2 and SPR effect of Bi particles, which provide new insights for the design of new and high-efficiency TiO2 photo-anode.

通过优化不同晶面暴露比例，可以促进光生载流子向不同晶面的转移与分离，而在不同晶面上选择性的进行异质结构修饰可以进一步促进载流子的空间分离，提高材料光电性能。本项目拟通过水热法在导电玻璃上原位生长单晶、垂直有序的锐钛矿纳米片阵列薄膜，以此TiO2纳米片阵列为基底，在{001}面沉积MoS2纳米片，构筑2D-2D的异质结构；在{101}和{001}晶面上选择性的进行Bi纳米粒子修饰，研究异质结构在不同晶面的选择性修饰、纳米片形貌、活性面暴露比对阵列薄膜的光电性能影响。结合理论计算，从{101}、{001}晶面以及Bi、MoS2能带结构出发，探究电荷转移及界面态相互作用协同促进的光电性能增强微观机制。该研究通过构筑晶面选择性修饰的Bi-MoS2-TiO2纳米片阵列，综合利用MoS2-TiO2间的电荷转移和Bi纳米粒子的表面等离子共振效应，为半导体光电转换材料的设计提供新的思路。

为了大幅度提高半导体复合材料光电性能，明晰异质界面对电荷转移与分离影响机制，我们提出从晶面调控和异质结修饰两方面改性材料的光电性能。本项目在FTO导电玻璃上原位生长晶面可控的氧化钛纳米片阵列，在不同晶面选择性的进行异质结构筑，综合运用了晶体内不同晶面形成的异质结和不同材料间形成的异质结的协同调控，进而增强材料的光电性能。项目通过水热原位生长、电沉积等方法，设计构筑了MoS2/TiO2阵列薄膜、Bi/TSTO纳米片阵列、α-Fe2O3/{101}TNS阵列薄膜、BVO/Cu2O薄膜电极，研究了其生长机制和光电化学性能，明晰了电荷转移及界面态相互作用协同促进的光电性能增强微观机制。该项目通过构筑晶面选择性修饰的异质结阵列薄膜，为设计与开发半导体光电材料提供了一个新思路，对拓展和提高材料在能源、环境等领域的应用具有重要的意义。