A Single-Junction Cathodic Approach for Stable Unassisted Solar Water Splitting
A Single-Junction Cathodic Approach for Stable Unassisted Solar Water Splitting
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DOI：
10.1016/j.joule.2019.07.022
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发表时间：
2019-10
期刊：
影响因子：
39.8
通讯作者：
Yongjie Wang;Yuanpeng Wu;Jonathan Schwartz;S. H. Sung;R. Hovden;Z. Mi
中科院分区：
文献类型：
--
作者：
Yongjie Wang;Yuanpeng Wu;Jonathan Schwartz;S. H. Sung;R. Hovden;Z. Mi
无辅助太阳能水分解是人工光合作用将太阳能转化为化学燃料的关键步骤之一。然而，到目前为止，还没有证明有效和稳定的半导体光电极没有额外的表面保护，用于无辅助的太阳能水分解。在这项工作中，我们表明，通过n++/p++-InGaN隧道结单片集成在n型Si晶片上的p型In0.25Ga0.75N纳米线的单结方法可以驱动相对有效和稳定的无辅助水分解。在零偏压下测量的光电流密度为2.8 mA cm− 2，而在双电极配置中的铂对电极，导致太阳能转化为氢气的效率为3.4%。在不使用任何额外表面保护层的情况下，未观察到200 h的无辅助太阳能水分解的性能降低。这种单结光电阴极可以进一步与窄带隙结集成，例如，Si或GaAs，以进一步提高长期稳定的太阳能水分解效率。
Unassisted solar water splitting is one key step of artificial photosynthesis converting solar energy to chemical fuels. To date, however, there has been no demonstration of efficient and stable semiconductor photoelectrodes without extra surface protection for unassisted solar water splitting. In this work, we show that a single-junction approach of p-type In0.25Ga0.75N nanowires monolithically integrated on n-type Si wafers through an n++/p++-InGaN tunnel junction can drive relatively efficient and stable unassisted water splitting. A photocurrent density of 2.8 mA cm−2was measured at zero bias versus a platinum counter electrode in a two-electrode configuration, leading to a solar-to-hydrogen efficiency of 3.4%. No performance degradation was observed for ∼300 h of unassisted solar water splitting without using any extra surface protection layers. Such a single-junction photocathode can be further integrated with a narrow band-gap junction, e.g., Si or GaAs, to achieve further improved efficiency for long-term stable solar water splitting.