Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 32000, Israel.
The Nancy & Stephen Grand Technion Energy Program (GTEP), Technion - Israel Institute of Technology, Haifa, 32000, Israel.
Adv Mater. 2018 Aug;30(35):e1802781. doi: 10.1002/adma.201802781. Epub 2018 Jul 10.
Optical interference is used to enhance light-matter interaction and harvest broadband light in ultrathin semiconductor absorber films on specular back-reflectors. However, the high-temperature processing in oxygen atmosphere required for oxide absorbers often degrades metallic back-reflectors and their specular reflectance. In order to overcome this problem, a newly developed film flip and transfer process is presented that enables high-temperature processing without degradation of the metallic back-reflector and without the need of passivation interlayers. The film flip and transfer process improves the performance of photoanodes for photoelectrochemical water splitting comprising ultrathin (<20 nm) hematite (α-Fe O ) films on silver-gold alloy (90 at% Ag-10 at% Au) back-reflectors. Specular back-reflectors are obtained with high reflectance below hematite films, which is necessary for maximizing the productive light absorption in the hematite film and minimizing nonproductive absorption in the back-reflector. Furthermore, the film flip and transfer process opens up a new route to attach thin film stacks onto a wide range of substrates including flexible or temperature sensitive materials.
光学干涉被用于增强光物质相互作用，并在镜面反射器上的超薄半导体吸收体薄膜中收集宽带光。然而，氧化物吸收体所需的在氧气环境中的高温处理通常会降低金属反射器及其镜面反射率。为了克服这个问题，提出了一种新的薄膜翻转和转移工艺，该工艺可以在不降低金属反射器的情况下进行高温处理，并且不需要钝化层。薄膜翻转和转移工艺提高了包含在银金合金（90at%Ag-10at%Au）反射器上的超薄（<20nm）赤铁矿（α-Fe2O3）薄膜的光电化学水分解光阳极的性能。在赤铁矿薄膜下方获得了具有高反射率的镜面反射器，这对于最大化赤铁矿薄膜中的有效光吸收和最小化反射器中的非有效吸收是必要的。此外，薄膜翻转和转移工艺为将薄膜堆叠附着到包括柔性或对温度敏感的材料在内的广泛的衬底上开辟了一条新途径。
