Photoelectrochemical Performance Enhancement of ZnSe Nanorods versus Dots: Combined Experimental and Computational Insights
Photoelectrochemical Performance Enhancement of ZnSe Nanorods versus Dots: Combined Experimental and Computational Insights
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ZnSe 纳米棒相对于点的光电化学性能增强：实验和计算相结合的见解
DOI：
10.1021/acs.jpclett.0c03254
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发表时间：
2020
影响因子：
5.7
通讯作者：
Zhang Ruiqin
中科院分区：
文献类型：
--
作者：
Huang Fei;Ning Jiajia;Xiong Wei;Zhao Yanling;Tian Jianjun;Rogach Andrey L.;Zhang Ruiqin
尺寸和形状可调的胶体半导体纳米晶是最有前途的光电化学分解水的材料之一。然而，在当代文献中仍然缺乏对胶体半导体NC的尺寸依赖的电荷载流子分离和输运的深入了解。在此，我们实验比较了具有相同立方结构（锌纳米）、相似体积和相似吸收边位置的无重金属的ZnSe纳米点和纳米棒的光电化学性能，并进行了密度泛函理论（DFT）计算以研究ZnSe点和棒的尺寸与电子结构之间的相关性。为了消除每个光阳极上不同沉积量的NR和ND的影响，我们量化了每个单个ZnSe点和棒的平均光电流密度贡献分别为5 × 10- 12和9 × 10-12μA·cm-2，这突出了棒相对于点的80%的显着PEC性能增强。密度泛函理论计算表明，一维形貌和晶面取向（<$111 <$）是导致ZnSe纳米晶具有极高跃迁偶极矩密度的主要因素，这有利于不同尺寸的ZnSe纳米晶的载流子分离和迁移率。该工作为胶体纳米晶光电化学性能增强机理提供了有益的见解，并有利于优化光电化学电池半导体材料的设计。
Size- and shape-tunable colloidal semiconductor nanocrystals are among the most promising materials for photoelectrochemical water splitting. However, in-depth insights into dimension-dependent charge carrier separation and transport for colloidal semiconductor NCs are still lacking in the contemporary literature. Herein, we experimentally compared photoelectrochemical performance of heavy-metal-free ZnSe nanodots and nanorods with the same cubic structure (zinc blende), similar volumes, and similar absorption edge positions and performed density functional theory (DFT) calculations to study the correlation between the dimension and the electronic structures of ZnSe dots and rods. To eliminate the influence of the different deposition amount of NRs and NDs on each phtoanode, we quantified an average photocurrent density contribution of each single ZnSe dot and rod to be 5 × 10–12and 9 × 10–12μA·cm–2, respectively, which highlights a significant PEC performance enhancement of 80% for rods versus dots. DFT calculations have shown that the one-dimensional morphology and crystal plane orientation (⟨111⟩) are both major factors for extremely high transition dipole moment density, which facilitate the charge carrier separation and mobility for ZnSe nanocrystals of different dimensions. This work provides useful insights into the mechanism of photoelectrochemical performance enhancement of colloidal nanocrystals and is beneficial for the design of semiconductor materials for optimal photoelectrochemical cells.