Fully Solution-Processable Photoelectrochemical Cells for Bias-Free Solar Water Splitting

Abstract

Solar production of hydrogen, the so-called artificial photosynthesis is getting more and more attention as a promising solution to modern energy and environmental problems. In principle, photoelectrochemical cells allows efficient production and separation of hydrogen by visible-light driven water electrolysis. However, conventional PEC devices have many limitations for their application such as low performance, low stability, complicate fabrication process, and the use of expensive material (e.g., Pt and Ru). To address these problems, we developed a fully solution-processable photoelectrochemical cells with cheap and abundant materials for bias-free solar water splitting. Unassisted solar water oxidation was enabled by constructing a PEC cell composed of BiVO4 photoanode and Cu2O photocathode modified by layer-by-layer assembly. It is found that the deposition of molecular polyelectrolytes and electrocatalysts on each electrode significantly improve their photoelectrochemical properties in terms of both performance and stability. We believe that the present study provides an insight and flexibility in the design and fabrication of future PEC devices.