Tandem Core-Shell Si-Ta3N5 Photoanodes for Photoelectrochemical Water Splitting
Tandem Core-Shell Si-Ta3N5 Photoanodes for Photoelectrochemical Water Splitting
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DOI：
10.1021/acs.nanolett.6b03408
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发表时间：
2016-12-01
期刊：
影响因子：
10.8
通讯作者：
Jaramillo, Thomas F.
中科院分区：
文献类型：
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作者：
Narkeviciute, Ieva;Chakthranont, Pongkarn;Jaramillo, Thomas F.
设计并合成了纳米结构核壳 Si-Ta3N5 光阳极，以克服 Ta3N5 在光电化学水分解中的电荷传输限制。核壳器件是通过将非晶 Ta2O5 原子层沉积到纳米结构 Si 上并随后氮化成结晶 Ta3N5 来制造的。与相同厚度的平面器件相比，具有 Ta3N5 薄壳的纳米结构可将光电流提高 10 倍。在检查 10 至 70 nm 范围内 Ta3N5 壳层的厚度依赖性时，从较薄的 Ta3N5 壳层获得了优异的光电流和吸收光子电流效率，表明少数载流子扩散长度约为数十纳米。基于半导体 n 型 Si 核的异质结构的制造产生了串联光电阳极，其光电流起始点向较低电势偏移了 200 mV。 CoTiOx 和 NiOx 水氧化助催化剂沉积在 Si Ta3N5 上，产生活性光阳极，在 24 小时计时安培实验后，NiOx 保留了最大光电流的 50-60%，因此是迄今为止报道的最稳定的 Ta3N5 光阳极之一。
Nanostructured core-shell Si-Ta3N5 photoanodes were designed and synthesized to overcome charge transport limitations of Ta3N5 for photoelectrochemical water splitting. The core shell devices were fabricated by atomic layer deposition of amorphous Ta2O5 onto nanostructured Si and subsequent nitridation to crystalline Ta3N5. Nanostructuring with a thin shell of Ta3N5 results in a 10-fold improvement in photocurrent compared to a planar device of the same thickness. In examining thickness dependence of the Ta3N5 shell from 10 to 70 nm, superior photocurrent and absorbed-photon-to-current efficiencies are obtained from the thinner Ta3N5 shells, indicating minority carrier diffusion lengths on the order of tens of nanometers. The fabrication of a heterostructure based on a semiconducting, n-type Si core produced a tandem photoanode with a photocurrent onset shifted to lower potentials by 200 mV. CoTiOx and NiOx water oxidation cocatalysts were deposited onto the Si Ta3N5 to yield active photoanodes that with NiOx retained 50-60% of their maximum photocurrent after 24 h chronoamperometry experiments and are thus among the most stable Ta3N5 photoanodes reported to date.