H2 evolution at Si-based metal-insulator-semiconductor photoelectrodes enhanced by inversion channel charge collection and H spillover
H2 evolution at Si-based metal-insulator-semiconductor photoelectrodes enhanced by inversion channel charge collection and H spillover
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DOI：
10.1038/nmat3626
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发表时间：
2013-06-01
期刊：
影响因子：
41.2
通讯作者：
Talin, A. Alec
中科院分区：
文献类型：
--
作者：
Esposito, Daniel V.;Levin, Igor;Talin, A. Alec
光电化学（PEC）水分解代表了一种有前景的可再生制氢途径，但光电极稳定性和效率之间的权衡极大地限制了PEC装置的性能。在这项工作中，我们采用了金属-绝缘体-半导体（MIS）光电极架构，可以使用窄带隙半导体实现稳定高效的水分解。通过将高质量的热SiO2层与双层金属催化剂的使用相结合，证明了硅基MIS光电阴极性能的显着提高。扫描探针技术用于同时绘制 MIS 表面的光伏和催化特性图，并揭示了 SiO2 表面溢出辅助的氢演化以及横向光电压驱动的少数载流子传输距离超过 2 厘米。后一个发现可以通过光和电解质诱导在 SiO2/Si 界面正下方形成反型通道来解释。这些发现对于MIS光电极的进一步发展具有重要意义，并为高效PEC水分解提供了可能性。
Photoelectrochemical (PEC) water splitting represents a promising route for renewable production of hydrogen, but trade-offs between photoelectrode stability and efficiency have greatly limited the performance of PEC devices. In this work, we employ a metal-insulator-semiconductor (MIS) photoelectrode architecture that allows for stable and efficient water splitting using narrow bandgap semiconductors. Substantial improvement in the performance of Si-based MIS photocathodes is demonstrated through a combination of a high-quality thermal SiO2 layer and the use of bilayer metal catalysts. Scanning probe techniques were used to simultaneously map the photovoltaic and catalytic properties of the MIS surface and reveal the spillover-assisted evolution of hydrogen off the SiO2 surface and lateral photovoltage driven minority carrier transport over distances that can exceed 2 cm. The latter finding is explained by the photo- and electrolyte-induced formation of an inversion channel immediately beneath the SiO2/Si interface. These findings have important implications for further development of MIS photoelectrodes and offer the possibility of highly efficient PEC water splitting.