Fu Jie, Fan Zeyu, Nakabayashi Mamiko, Ju Huanxin, Pastukhova Nadiia, Xiao Yequan, Feng Chao, Shibata Naoya, Domen Kazunari, Li Yanbo
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, China.
Yangtza Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou, China.
Nat Commun. 2022 Feb 7;13(1):729. doi: 10.1038/s41467-022-28415-4.
Interface engineering is a proven strategy to improve the efficiency of thin film semiconductor based solar energy conversion devices. TaN thin film photoanode is a promising candidate for photoelectrochemical (PEC) water splitting. Yet, a concerted effort to engineer both the bottom and top interfaces of TaN thin film photoanode is still lacking. Here, we employ n-type In:GaN and p-type Mg:GaN to modify the bottom and top interfaces of TaN thin film photoanode, respectively. The obtained In:GaN/TaN/Mg:GaN heterojunction photoanode shows enhanced bulk carrier separation capability and better injection efficiency at photoanode/electrolyte interface, which lead to a record-high applied bias photon-to-current efficiency of 3.46% for TaN-based photoanode. Furthermore, the roles of the In:GaN and Mg:GaN layers are distinguished through mechanistic studies. While the In:GaN layer contributes mainly to the enhanced bulk charge separation efficiency, the Mg:GaN layer improves the surface charge inject efficiency. This work demonstrates the crucial role of proper interface engineering for thin film-based photoanode in achieving efficient PEC water splitting.
界面工程是提高基于薄膜半导体的太阳能转换器件效率的一种行之有效的策略。TaN薄膜光阳极是光电化学（PEC）水分解的一个有前景的候选材料。然而，目前仍缺乏对TaN薄膜光阳极的底部和顶部界面进行协同工程设计的努力。在此，我们分别采用n型In:GaN和p型Mg:GaN来修饰TaN薄膜光阳极的底部和顶部界面。所制备的In:GaN/TaN/Mg:GaN异质结光阳极表现出增强的体载流子分离能力以及在光阳极/电解质界面处更好的注入效率，这使得基于TaN的光阳极的施加偏压光子到电流效率达到创纪录的3.46%。此外，通过机理研究区分了In:GaN和Mg:GaN层的作用。虽然In:GaN层主要有助于提高体电荷分离效率，但Mg:GaN层提高了表面电荷注入效率。这项工作证明了适当的界面工程对于基于薄膜的光阳极实现高效PEC水分解的关键作用。
