All Printed Photoanode/Photovoltaic Mini-Module for Water Splitting.

Printing a large-area bismuth vanadate photoanode offers a promising approach for cost-effective photoelectrochemical (PEC) water splitting. However, the light absorption trade-off with charge transfer, as well as stability issues always lead to poor PEC efficiency. Here, the solution-processed recipe is advanced with BiI dopant for the printed deposition with controllable crystal growth. The resultant BiVO films prefer (001) orientation with nanorod feature on substrate, allowing a faster charge transfer and improved photocurrent. The BiVO photoanode in tandem with perovskite solar module delivers an operating photocurrent density of 5.88 mA cm at zero bias in 3.11 cm active area under AM 1.5 G illumination, yielding a solar-to-hydrogen efficiency as high as 7.02% for unbiased water splitting. Equally important, the stability of the aged BiVO rods has been addressed to distinguish phase segregation at surface. The photocatalysis degradation composes of vanadium loss and Bi O enriching at the surface, opening a lid on the long-term stability of BiVO photoanodes.