Urbain Félix, Tang Pengyi, Smirnov Vladimir, Welter Katharina, Andreu Teresa, Finger Friedhelm, Arbiol Jordi, Morante Joan Ramón
IREC, Catalonia Institute for Energy Research, Jardins de les Dones de Negre 1, 08930 Sant Adrià de Besòs, Barcelona, Catalonia, Spain.
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain.
ChemSusChem. 2019 Apr 5;12(7):1428-1436. doi: 10.1002/cssc.201802845. Epub 2019 Feb 27.
The concept of hybrid tandem device structures that combine metal oxides with thin-film semiconducting photoabsorbers holds great promise for large-scale, robust, and cost-effective bias-free photoelectrochemical water splitting (PEC-WS). This work highlights important steps toward the efficient coupling of high-performance hematite photoanodes with multijunction thin-film silicon photocathodes providing high bias-free photocurrent density. The hybrid PEC-WS device is optimized by testing three types of multijunction silicon photocathodes with the hematite photoanode: amorphous silicon (a-Si:H) tandem: a-Si:H/a-Si:H and triple junction with microcrystalline silicon (μc-Si:H): a-Si:H/a-Si:H/μc-Si:H and a-Si:H/μc-Si:H/μc-Si:H. The results provide evidence that the multijunction structures offer high flexibility for hybrid tandem devices with regard to tunable photovoltages and spectral matching. Furthermore, both photoanode and photocathode are tested under various electrolyte and light concentration conditions, respectively, with respect to their photoelectrochemical performance and stability. A 27 % enhancement in the solar-to-hydrogen conversion efficiency is observed upon concentrating light from 100 to 300 mW cm . Ultimately, bias-free water splitting is demonstrated, with a photocurrent density of 4.6 mA cm (under concentrated illumination) paired with excellent operation stability for more than 24 h of the all-earth-abundant and low-cost hematite/silicon tandem PEC-WS device.
将金属氧化物与薄膜半导体光吸收体相结合的混合串联器件结构概念，对于大规模、稳健且具有成本效益的无偏压光电化学水分解（PEC-WS）具有巨大潜力。这项工作突出了高性能赤铁矿光阳极与多结薄膜硅光阴极高效耦合的重要步骤，该光阴极可提供高无偏压光电流密度。通过测试三种类型的多结硅光阴极与赤铁矿光阳极来优化混合PEC-WS器件：非晶硅（a-Si:H）串联：a-Si:H/a-Si:H，以及含微晶硅（μc-Si:H）的三结：a-Si:H/a-Si:H/μc-Si:H和a-Si:H/μc-Si:H/μc-Si:H。结果表明，多结结构在混合串联器件的可调光电压和光谱匹配方面具有高度灵活性。此外，分别在各种电解质和光浓度条件下测试了光阳极和光阴极的光电化学性能及稳定性。当光从100 mW/cm² 聚光到300 mW/cm² 时，观察到太阳能到氢能的转换效率提高了27%。最终，展示了无偏压水分解，在全地球丰富且低成本的赤铁矿/硅串联PEC-WS器件中，光电流密度为4.6 mA/cm²（在聚光照明下），并具有超过24小时的出色运行稳定性。
