Reticulated Mesoporous TiO2 Scaffold, Fabricated by Spray Coating, for Large‐Area Perovskite Solar Cells

Development of reproducible, low‐cost fabrication technologies that are readily adaptable to large‐scale production, is one of the main challenges in the field of perovskite solar cells (PSCs). So far, for all the other layers in a solar cell, large‐area deposition methods have been adapted, except for mesoporous fabrication. Herein, the fabrication of mesoporous TiO2 scaffolds using a large‐area deposition technique, such as spray coating, is shown. Moreover, this technique induces the formation of a very specific reticulated structure with well‐delimited, oval‐shaped cavities. The cavities have irregular dimensions, with diameters in the range of 3–7 μm, ≈350 nm height, resulting in an overall increase in roughness of one order of magnitude, compared with the spin‐coated mesoporous scaffold. Using this rough structured mesoporous TiO2 in PSCs not only does not affect the efficiency of solar cells but actually improves it from an average of 10% to 12% in comparison with the devices containing a spin‐coated mesoporous scaffold. Herein, the fabrication of mesoporous TiO2 scaffolds using a large‐area deposition technique, spray coating, is presented. The technique induces the formation of a specific reticulated structure with well‐delimited cavities, resulting in an overall increase in roughness of one order of magnitude, compared with spin‐coated mesoporous scaffolds. This mesoporous TiO2 scaffold improves the power conversion efficiency (PCE) of perovskite solar cells.