Efficient solar water splitting by enhanced charge separation in a bismuth vanadate-silicon tandem photoelectrode
Efficient solar water splitting by enhanced charge separation in a bismuth vanadate-silicon tandem photoelectrode
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DOI：
10.1038/ncomms3195
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发表时间：
2013-07-01
影响因子：
16.6
通讯作者：
van de Krol, Roel
中科院分区：
文献类型：
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作者：
Abdi, Fatwa F.;Han, Lihao;van de Krol, Roel
金属氧化物通常在水溶液中非常稳定并且便宜，但是它们的光化学活性通常受到差的载流子分离的限制。在这里，我们表明，这个问题可以通过在金属氧化物膜中引入梯度掺杂剂浓度，从而产生分布式n（+）-n同质结来解决。这一概念证明了低成本，喷雾沉积和无孔钨掺杂钒酸铋光阳极，其中实现高达80%的载流子分离效率。通过将这种最先进的光阳极与地球上丰富的磷酸钴水氧化催化剂和双结或单结非晶硅太阳能电池串联配置相结合，在1个太阳照射下分别实现了类似于4和3 mA cm（-2）的稳定短路水裂解光电流。4 mA cm（-2）光电流对应于4.9%的太阳能-氢气效率，这是基于金属氧化物光阳极的独立水裂解装置的最高效率。
Metal oxides are generally very stable in aqueous solutions and cheap, but their photochemical activity is usually limited by poor charge carrier separation. Here we show that this problem can be solved by introducing a gradient dopant concentration in the metal oxide film, thereby creating a distributed n(+) -n homojunction. This concept is demonstrated with a low-cost, spray-deposited and non-porous tungsten-doped bismuth vanadate photoanode in which carrier-separation efficiencies of up to 80% are achieved. By combining this state-of-the-art photoanode with an earth-abundant cobalt phosphate water-oxidation catalyst and a double-or single-junction amorphous Si solar cell in a tandem configuration, stable short-circuit water-splitting photocurrents of similar to 4 and 3 mA cm(-2), respectively, are achieved under 1 sun illumination. The 4 mA cm(-2) photocurrent corresponds to a solar-to-hydrogen efficiency of 4.9%, which is the highest efficiency yet reported for a stand-alone water-splitting device based on a metal oxide photoanode.