Periodic Micropillar-Patterned FTO/BiVO₄ with Superior Light Absorption and Separation Efficiency for Efficient PEC Performance

In this study, a high-performance photoanode based on 3D periodic, micropillar-structured fluorine-doped tin oxide (FTO-MP) deposited with BiVO₄ is fabricated using the patterned FTO by direct printing and spray pyrolysis, followed by the deposition of BiVO₄ by sputtering and V ion heat-treatment on the patterned FTO. The FTO-MP enables light scattering owing to its 3D periodic structure and increases the light absorption efficiency. In addition, the high electron mobility of FTO and enlarged surface area of FTO-MP enhance the separation efficiency. Due to the combination of these enhancing strategies, the photocurrent density of micropillar-patterned BiVO₄ at 1.23 V_RHE reached 2.97 mA cm⁻², which is 67.8% higher than that of flat BiVO₄. The results suggest that the efficiency can increase significantly using the patterned FTO fabricated by an inexpensive and simple process (i.e., direct printing and spray pyrolysis), thereby indicating a new strategy for the enhancement of efficiency in various energy fields.