Development of a corrosion-resistant amorphous silicon carbide photoelectrode for solar-to-hydrogen photovoltaic/photoelectrochemical devices
Development of a corrosion-resistant amorphous silicon carbide photoelectrode for solar-to-hydrogen photovoltaic/photoelectrochemical devices
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开发用于太阳能-氢光伏/光电化学装置的耐腐蚀非晶碳化硅光电极
DOI：
10.1117/12.794287
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Arun Madan
中科院分区：
文献类型：
--
作者：
I. Matulionis;F. Zhu;Jian Hu;T. Deutsch;A. Kunrath;E. Miller;B. Marsen;Arun Madan
光电化学（PEC）在半导体-电解质界面上利用阳光进行水分解是非常有趣的，因为它提供了一种清洁的制氢方法。PEC电池需要半导体光电极材料满足许多重要的要求，如带边对准，耐电解质腐蚀，和足够的电流产生。我们报道了rf - pecvd沉积氢化非晶碳化硅（a-SiC:H）光电极的开发，该电极具有更高的耐久性，当与a-Si:H串联光伏器件结合时，可以在阳光下直接从水中产生氢。a- sic:H通常生长在超过2.0 eV的带隙中，并通过提供与电解质的接触，适当的带边对齐来完成PEC器件，并作为a- si:H串联结构的缓冲。电解质的pH值、衬底类型和铂纳米颗粒涂层对a- sic光电极耐久性的影响将被提出。从这些研究中我们推测，a-SiC:H层发生腐蚀或损伤的机理可分为物理和化学两个方面。从物理角度来看，经SEM（扫描电子显微镜）和EDS（能量色散x射线光谱学）研究证实，与纹理TCO衬底、不锈钢粗糙度或其他针孔来源的尖峰相关的缺陷可能引发分层。从化学上讲，氢气的生产涉及到可能腐蚀电极的反应，特别是当涉及到物理缺陷时。我们观察到，降低电解液的酸度（将pH从0提高到2）可以显著减少腐蚀，而a-SiC:H /i结构的有用光电流输出不受影响。
Photoelectrochemical (PEC) water splitting at a semiconductor-electrolyte interface using sunlight is of considerable interest as it offers a clean approach to hydrogen production. PEC cells require semiconductor photoelectrode materials fulfilling a number of important requirements, such as band-edge alignment, corrosion resistance to electrolyte, and adequate current generation. We report the development of RF-PECVD-deposited hydrogenated amorphous silicon carbide (a-SiC:H) photoelectrodes with improved durability, which, when combined with a-Si:H tandem photovoltaic devices, should produce hydrogen directly from water under sunlight. The a-SiC:H is commonly grown with a bandgap in excess of 2.0 eV and completes the PEC device by providing contact with the electrolyte, proper band-edge alignment, and acts as a buffer for the a-Si:H tandem structure. Effects of the pH of electrolyte, type of substrates, and a platinum nanoparticle coating on the durability of a-SiC photoelectrodes will be presented. From these studies we surmise that corrosion or damage mechanism occurring on a-SiC:H layer could be divided into different aspects of physical and chemical. From the physical point of view, defects associated with spikes in textured TCO substrates, roughness of stainless steel, or other sources of pinholes may initiate delamination as confirmed by SEM (Scanning Electron Microscopy) and EDS (Energy-Dispersive X-ray Spectroscopy) studies. Chemically, the production of hydrogen involves reactions that may etch the electrode, especially when physical defects are involved. We observe that reducing the acidity of the electrolyte (increasing the pH from 0 to 2) significantly reduces corrosion while the useful photocurrent output of the a-SiC:H p/i structure is unaffected.