Shi Yanuo, Wang Luyao, Wang Ziyu, Vinai Giovanni, Braglia Luca, Torelli Piero, Aruta Carmela, Traversa Enrico, Liu Weimin, Yang Nan
Electrochemical Thin Film Group, School of Physical Science and Technology, ShanghaiTech University, Shanghai, P.R. China.
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, P.R. China.
ACS Appl Mater Interfaces. 2021 Jan 13;13(1):541-551. doi: 10.1021/acsami.0c17921. Epub 2020 Dec 29.
Solid oxide photoelectrochemical cells (SOPECs) with inorganic ion-conducting electrolytes provide an alternative solution for light harvesting and conversion. Exploring potential photoelectrodes for SOPECs and understanding their operation mechanisms are crucial for continuously developing this technology. Here, ceria-based thin films were newly explored as photoelectrodes for SOPEC applications. It was found that the photoresponse of ceria-based thin films can be tuned both by Sm-doping-induced defects and by the heating temperature of SOPECs. The whole process was found to depend on the surface electrochemical redox reactions synergistically with the bulk photoelectric effect. Samarium doping level can selectively switch the open-circuit voltages polarity of SOPECs under illumination, thus shifting the potential of photoelectrodes and changing their photoresponse. The role of defect chemistry engineering in determining such a photoelectrochemical process was discussed. Transient absorption and X-ray photoemission spectroscopies, together with the state-of-the-art X-ray absorption spectroscopy, allowed us to provide a compelling explanation of the experimentally observed switching behavior on the basis of the surface reactions and successive charge balance in the bulk.
具有无机离子传导电解质的固体氧化物光电化学电池（SOPEC）为光捕获和转换提供了一种替代解决方案。探索SOPEC的潜在光电极并了解其运行机制对于持续发展这项技术至关重要。在此，基于二氧化铈的薄膜被新探索用作SOPEC应用的光电极。发现基于二氧化铈的薄膜的光响应可以通过钐掺杂诱导的缺陷以及SOPEC的加热温度来调节。发现整个过程取决于表面电化学氧化还原反应与体相光电效应的协同作用。钐掺杂水平可以在光照下选择性地切换SOPEC的开路电压极性，从而改变光电极的电位并改变其光响应。讨论了缺陷化学工程在确定这种光电化学过程中的作用。瞬态吸收和X射线光电子能谱，以及最先进的X射线吸收光谱，使我们能够基于表面反应和体相中的连续电荷平衡，对实验观察到的开关行为提供令人信服的解释。
