Vacuum-free fabrication of organic solar cell on assembled glass substrates

Vacuum-free fabrication is essential to realize large-scale production of organic solar cells. Blade-coating and printing are important solution-processing techniques to realize this idea. Preparation devices on large substrates is important for mass production; however, it is not easy to handle large substrates during fabrication procedures. In this work, we demonstrate a fabrication method for all-solution vacuum-free organic solar cells on an assembled glass substrates. Small pieces of glasses were assembled into a mosaic of larger total size for device fabrication. A gap-prefilling method was also developed to realize uniform thickness distribution. For the device with blade-coated ZnO electron transport layer, blade-coated active layer, spray-coated hole transport layer and spray-coated top electrode, power conversion efficiency of 4.19% is obtained. This showed that, by combining spray and blade coating, ultimate scale of the vacuum-free fabrication of OPV on glass substrate will not be limited by the substrate size itself, and can be scaled up to multi-meter by assembling the glasses into a mosaic.