Interfacial oxygen vacancies yielding long-lived holes in hematite mesocrystal-based photoanodes
Interfacial oxygen vacancies yielding long-lived holes in hematite mesocrystal-based photoanodes
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DOI：
10.1038/s41467-019-12581-z
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发表时间：
2019-10
影响因子：
16.6
通讯作者：
Zhujun Zhang;Izuru Karimata;H. Nagashima;S. Muto;K. Ohara;K. Sugimoto;T. Tachikawa
中科院分区：
文献类型：
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作者：
Zhujun Zhang;Izuru Karimata;H. Nagashima;S. Muto;K. Ohara;K. Sugimoto;T. Tachikawa
赤铁矿（α-Fe 2 O3）是最有希望作为太阳能分解水的光阳极材料之一。然而，由于难以抑制显着的电荷复合，光电化学（PEC）转换效率的赤铁矿仍然远远低于理论极限。在这里，我们报告厚的赤铁矿膜（约1500 nm）的高度有序和紧密连接的赤铁矿介晶（MC）的高效PEC水氧化。由于形成了大量的界面氧空位，产生了高达1020 cm-3的高载流子密度，以及在分层结构中产生了极大比例的具有短耗尽宽度（<10 nm）的耗尽区，电荷分离和收集效率可以显着提高。此外，发现通过较短波长的光（低于500 nm）的激发产生长寿命的电荷，从而使得能够通过MC网络进行长距离空穴转移，以在背照下驱动高效率的光能转换。
Hematite (α-Fe2O3) is one of the most promising candidates as a photoanode materials for solar water splitting. Owing to the difficulty in suppressing the significant charge recombination, however, the photoelectrochemical (PEC) conversion efficiency of hematite is still far below the theoretical limit. Here we report thick hematite films (∼1500 nm) constructed by highly ordered and intimately attached hematite mesocrystals (MCs) for highly efficient PEC water oxidation. Due to the formation of abundant interfacial oxygen vacancies yielding a high carrier density of ∼1020cm−3and the resulting extremely large proportion of depletion regions with short depletion widths (<10 nm) in hierarchical structures, charge separation and collection efficiencies could be markedly improved. Moreover, it was found that long-lived charges are generated via excitation by shorter wavelength light (below ∼500 nm), thus enabling long-range hole transfer through the MC network to drive high efficiency of light-to-energy conversion under back illumination.