The fabrication of organic photovoltaic modules via printing techniques has been the greatest challenge for their commercial manufacture. Current module architecture, which is based on a monolithic geometry consisting of serially interconnecting stripe-patterned sub-cells with finite widths, requires highly sophisticated patterning processes that significantly increase the complexity of printing production lines and cause serious reductions in module efficiency due to so-called ‘aperture loss’ in series connection regions. In this study, we demonstrate an innovative module structure that can simultaneously reduce both patterning processes and aperture loss. By using a charge recombination feature that occurs at contacts between electron/hole transport layers, we devise a series connection method that facilitates module fabrication without patterning the charge transport layers. With the successive deposition of component layers using slot-die and doctor-blade printing techniques, we achieve a high module efficiency reaching 7.5% with area of 4.15 cm2.
The formation of pinhole-free perovskite photoactive films with full surface coverage has been a tremendous challenge for up-scaling planar perovskite solar cells (PSCs) while maintaining their high power conversion efficiencies (PCEs). Particularly, a significant mismatch between the surface energies of a hydrophilic perovskite precursor solution and a hydrophobic organic charge transport layer (CTL) has been a major cause for the poor and random surface coverage of perovskite photoactive films, which drastically reduces the scalability and reproducibility of PSCs. Here, we report a universal method to create extremely compact perovskite photoactive films on a variety of hydrophobic CTLs. By introducing an amphiphilic conjugated polyelectrolyte as an interfacial compatibilizer, we succeed in improving the wettability of perovskite precursor solutions on hydrophobic CTLs and fabricating perovskite photoactive films over large areas. Our approach enables the scalable fabrication of planar PSCs with large areas (1 cm2, PCE of 17%) while preserving nearly 90% of the PCEs of the corresponding small-area devices (PCE of 19%).