Efficient Large Area Semi-Transparent Dye-Sensitized Solar Cells (DSSCs) Printed with DMD400 Technology

This work presents the development of fully printed, large-area, semi-transparent Dye-Sensitized Solar Cells (DSSCs) using TiO₂ nanoparticles treated with TiCl₄, a “D35” push-pull dye sensitizer, and I₃⁻/I⁻ redox mediator. Cells with areas of 4 and 200 cm² were printed using hexagonal, stripe, and standard designs, employing digital materials deposition (DMD) technology. The porous films printed via DMD, confirmed by scanning electron microscopy (SEM), improved solar cells performance by enhancing the Open Circuit Voltage (Voc) and fill factor (FF). The hexagonal design, in particular, facilitated better electrolyte impregnation in the TiO₂ mesoporous structure, boosting current density. This design yielded a power conversion efficiency (PCE) of 7.05% for 4 cm² DSSCs, surpassing the stripe (5.50%) and standard (5.48%) designs. Its higher performance can be attributed to lower interfacial charge recombination rates and improvedcharge transfer and collection efficiency. Photophysical measurements indicated faster charge transfer rates in hexagonal cells (≈ 1.3  ×  10⁹s⁻¹) compared to the stripe (9.8  ×  10⁸ s⁻¹) and standard (9.5  ×  10⁸ s⁻¹) designs. Hence, our work highlights the potential of hexagonal design to improve both efficiency and transparency while reducing material consumption, offering a promising approach for manufacturing semi-transparent solar cells.