Factors to be considered in bulk heterojunction polymer solar cells fabricated by the spray process

One of the attractions of solution-processed polymer solar cells (PSCs) is the potential for low-cost production by high-throughput roll-to-roll processes. The spray process can be suggested as an elegant alternative for PSCs fabrication due to its high production speed. We highlight the effects of sprayed droplet sizes on the film topography and drying time of droplets. We relate the latter to the PSCs device performances. The transfer efficiency and deposition rate of the spray process as a function of the droplet size are investigated for the high production speed and lowering the cost. PSC device fabrication with an optimized spray-operating condition yielded a power conversion efficiency of 3.4. The comparable efficiency of PSCs fabricated by a roll-to-roll compatible process compared to spin-coated one achieved in this paper brings these devices one step closer to the realization of low-cost PSCs production.