Facet Cutting and Hydrogenation of In2O3 Nanowires for Enhanced Photoelectrochemical Water Splitting
Facet Cutting and Hydrogenation of In2O3 Nanowires for Enhanced Photoelectrochemical Water Splitting
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用于增强光电化学水分解的 In2O3 纳米线的小面切割和氢化
DOI：
10.1021/am4056358
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发表时间：
2014-03-26
影响因子：
9.5
通讯作者：
Chu, Paul K.
中科院分区：
文献类型：
--
作者：
Meng, Ming;Wu, Xinglong;Chu, Paul K.
半导体纳米线是光电、传感、能源等领域的重要组成部分，一维纳米线具有光吸收和电荷传输的特性，被广泛应用于光电化学（PEC）水分解。理论预测体心立方（bcc）In 2 O3纳米晶的{001}晶面在光照下可以有效地积累光生空穴，但切割纳米线晶面是否能提高PEC水裂解效率尚不清楚。在这项工作中，观察到具有四个{001}面的正方形In 2 O3纳米线的光电流比相同条件下的圆柱形In 2 O3纳米线的光电流大一个数量级，并且随后的氢处理进一步促进了纳米线的PEG水裂解性能。优化的氢化In 2 O3纳米线在0.22 V（Ag/AgCl）下产生1.2 mA/cm（2）的光电流密度，法拉第效率约为84.4%。增强的PEC性能可以归因于由于无序层诱导的带尾态与价带的合并以及In 2 O3晶体核心和无序层界面之间的光生电子/空穴的分离的改善而减小的带隙。这一结果为刻面切割的重要作用提供了实验依据，在近紫外光电器件的设计和制造中具有重要的应用前景。
Semiconductor nanowires (NWs) are useful building blocks in optoelectronic, sensing, and energy devices and one-dimensional NWs have been used in photoelectrochemical (PEC) water splitting because of the enhanced light absorption and charge transport. It has been theoretically predicted that the {001} facets of body center cubic (bcc) In2O3 nanocrystals can effectively accumulate photogenerated holes under illumination, but it is unclear whether facet cutting of NWs can enhance the efficiency of PEC water splitting. In this work, the photocurrent of square In2O3 NWs with four {001} facets is observed to be an order of magnitude larger than that of cylindrical In2O3 NWs under the same conditions and subsequent hydrogen treatment further promotes the PEG water splitting performance of the NWs. The optimized hydrogenated In2O3 NWs yield a photocurrent density of 1.2 mA/cm(2) at 0.22 V versus Ag/AgCl with a Faradaic efficiency of about 84.4%. The enhanced PEC properties can be attributed to the reduced band gap due to merging of the disordered layer-induced band tail states with the valence band as well as improved separation of the photogenerated electrons/holes between the In2O3 crystal core and disordered layer interface. The results provide experimental evidence of the important role of facet cutting, which is promising in the design and fabrication of NW-based photoelectric devices.