Abstract
Photoelectrochemical (PEC) water splitting is an eco-friendly energy generation process that gives rise to a hydrogen source as a result of the redox reaction of water, using the energy of absorbed light. Because of the process involved, the overall efficiency is expressed as a product of the light absorption efficiency (ηabs), the charge separation efficiency (ηsep) and the charge transfer efficiency (ηtrans). PEC water splitting is difficult to commercialize because of its low efficiency and difficulty in applying to a large area. In order to alleviate these problems, considerable amount of research has gone into pattern to increase the efficiency of PEC itself and on the PEC-PSC tandem cell, which is the combination of a perovskite solar cell and PEC. However, until now, studies on applying pattern engineering to PEC have been restricted to the use of Au or Pt as electrodes. In this case, despite of gaining the advantage of the effect of pattern, it also has the disadvantages of being unsuitable of PEC-PSC tandem cell (due to the opacity of Au and Pt) and being impractical for application to the field of energy research (due to Au and Pt being very expensive).In the work presented in the submitted manuscript, we have studied the increase in PEC efficiency by forming a patterned FTO. The patterned FTO, formed by direct printing, is transparent and cheaper than Au and Pt, making it a suitable electrode for applications in energy research as well as in a PEC-PSC tandem cell. It also has the desired effect of pattern. In the case of Au or Pt electrode, hydrothermal synthesis is of limited use as Au and Pt are detached due to the oxidation of Cr used as an adhesion layer. However, due to the high stability of FTO, hydrothermal synthesis is possible in our case.we fabricated a flat Fluorine-doped SnO2 (FTO) electrode and a micro cone structured FTO electrode. We then fabricated a WO3 nanoflakes (NF)/BiVO4 photoanode on top of each of these two types of FTOs. The photocurrent density of WO3/BiVO4 on micro cone patterned FTO reached 1.50 mA/cm2 at 1.23 VRHE, which is 34 % higher than the that of WO3/BiVO4 on flat FTO(1.12 mA/cm2). When measured with 0.5 M Na2SO3, the photocurrent densities of FB-WO3/BiVO4 and B-WO3/BiVO4 were found to be 2.48 and 1.80 mA/cm2, respectively, at 1.23 VRHE. These results show the same trend as the (J – V) curve.Our study was successful in increasing PEC efficiency by patterning transparent and cheap electrode materials (FTO), suitable for applications in PEC-PSC tandem cells, using direct printing. The significant advance demonstrated here indicates that it is possible to fabricate high efficiency PEC-PSC tandem cell using the FTO architecture, and to facilitate large-area PEC commercialization by using processes suitable for large-scale productions (namely direct printing, spray pyrolysis, and hydrothermal reaction). Figure 1
Published Version
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