Hajibabaei Hamed, Zandi Omid, Hamann Thomas W
Michigan State University , Department of Chemistry , 578 S Shaw Lane , East Lansing , Michigan 48824-1322 , USA . Email:
Chem Sci. 2016 Nov 1;7(11):6760-6767. doi: 10.1039/c6sc02116f. Epub 2016 Jul 5.
Tantalum nitride, TaN, is one of the most promising materials for solar energy driven water oxidation. One significant challenge of this material is the high temperature and long duration of ammonolysis previously required to synthesize it, which has so far prevented the use of transparent conductive oxide (TCO) substrates to be used which would allow sub-bandgap light to be transmitted to a photocathode. Here, we overcome this challenge by utilizing atomic layer deposition (ALD) to directly deposit tantalum oxynitride thin films, which can be fully converted to TaN ammonolysis at 750 °C for 30 minutes. This synthesis employs far more moderate conditions than previous reports of efficient TaN photoanodes. Further, we report the first ALD of Ta-doped TiO which we show is a viable TCO material that is stable under the relatively mild ammonolysis conditions employed. As a result, we report the first example of a TaN electrode deposited on a TCO substrate, and the photoelectrochemical behavior. These results open the door to achieve efficient overall water splitting using a TaN photoanode.
氮化钽（TaN）是太阳能驱动水氧化最具潜力的材料之一。这种材料面临的一个重大挑战是，此前合成它需要高温和长时间的氨解反应，这至今阻碍了使用透明导电氧化物（TCO）衬底，而这种衬底能使子带隙光传输到光阴极。在此，我们通过利用原子层沉积（ALD）直接沉积氮氧化钽薄膜来克服这一挑战，该薄膜在750℃下氨解30分钟可完全转化为TaN。这种合成方法采用的条件比之前关于高效TaN光阳极的报道温和得多。此外，我们报道了首次Ta掺杂TiO的ALD，结果表明它是一种可行的TCO材料，在相对温和的氨解条件下稳定。因此，我们报道了首个沉积在TCO衬底上的TaN电极及其光电化学行为。这些结果为使用TaN光阳极实现高效全解水打开了大门。
