Enhancing large-area photoelectrochemical cells' performance through conductivity improvement of customizable FTO collectors grid

Abstract

Photoelectrochemical cells, including dye-sensitized solar cells (DSSCs) and water-splitting systems (PEC-WS), offer the significant advantage of directly converting solar energy into electricity and/or fuel. However, their commercial viability is limited by upscaling challenges, particularly due to the reliance on transparent conductive electrodes, which allow for effective visible light transmission and charge collection yet display ohmic losses arising from the electrical resistance across larger dimensions substrates. Identifying an alternative electrode material suitable across PEC technologies has been challenging due to manufacturing requirements and long-term photostability incompatibility.

In this study, we developed and evaluated fluorine-doped tin oxide (FTO)-coated glass substrates integrated with FTO current collectors as an efficient and stable strategy for upscaling PEC devices. Multiphysics simulations were employed to assess various FTO mesh designs, evaluating the impact of collector density and geometry on the conductivity of the FTO substrates. The optimized configurations were implemented on FTO-coated glasses via ultrasonic spray-pyrolysis, with deposition parameters finely tuned. Large-area DSSCs and PEC-WS devices, featuring a photoactive area of 25 cm², were assembled with FTO-mesh substrates and exhibited a stable operation with best-performing designs, achieving solar energy conversion efficiencies ca. 2.1 and 1.2 times, respectively higher than collector-less DSSC and PEC-WS reference counterparts.