Successive redox-mediated visible-light ferrophotovoltaics
Successive redox-mediated visible-light ferrophotovoltaics
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DOI：
10.1038/s41467-020-14763-6
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发表时间：
2020-02
影响因子：
16.6
通讯作者：
Y. Noguchi;Y. Taniguchi;R. Inoue;M. Miyayama
中科院分区：
文献类型：
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作者：
Y. Noguchi;Y. Taniguchi;R. Inoue;M. Miyayama
二氧化钛材料具有光催化、光伏效应等多种功能。铁电体提供了光能转换的途径，可提供因空间反演对称性破缺而产生的高于带隙的电压，而它们的宽带隙导致可见光吸收不良。带隙变窄提供了一种潜在的解决方案，但这种材料改性抑制了自发极化，因此牺牲了光电压。在这里，我们报告了连续氧化还原介导的铁光伏电池，其表现出强大的可见光响应。我们的单晶实验和从头计算以及光致发光分析表明，二价 Fe2+ 和三价 Fe3+ 共存于原型铁电钛酸钡 BaTiO3 中，分别引入供体和受体水平，并且两个连续的 Fe3+/Fe2+ 氧化还原反应不仅在可见光下而且在大于带隙的光子能量下增强了光生功率。我们的方法为光伏发电以及潜在的光催化剂的可见光激活开辟了一条有前途的途径。
Titanium oxide materials have multiple functions such as photocatalytic and photovoltaic effects. Ferroelectrics provide access to light energy conversion that delivers above-bandgap voltages arising from spatial inversion symmetry breaking, whereas their wide bandgap leads to poor absorption of visible light. Bandgap narrowing offers a potential solution, but this material modification suppresses spontaneous polarization and, hence, sacrifices photovoltages. Here, we report successive-redox mediated ferrophotovoltaics that exhibit a robust visible-light response. Our single-crystal experiments and ab initio calculations, along with photo-luminescence analysis, demonstrate that divalent Fe2+and trivalent Fe3+coexisted in a prototypical ferroelectric barium titanate BaTiO3introduce donor and acceptor levels, respectively, and that two sequential Fe3+/Fe2+redox reactions enhance the photogenerated power not only under visible light but also at photon energies greater than the bandgap. Our approach opens a promising route to the visible-light activation of photovoltaics and, potentially, of photocatalysts.