Organic Photovoltaics, from Lab to Fab

The communication will display our recent progress Organic Photovoltaics (OPV). Solution-processed organic solar cells are continuously showing increasing performances other the recent years with record power conversion efficiency exceeding 15%. They represent a more and more promising technology with a growing interest from companies and markets. The challenge is surely to maintain the global research efforts in materials development to increase efficiency and stability but also to enable a realistic cost-competitve transfer from lab to fab. Our efforts to increase the stability of OPV cells will be exposed including device engineering and materials developments for thermally stable devices. We have recently shown that impurities such as photo-oxidized fullerene or photo-oxidized polymers (P3HT or PTB7) are responsible for an impressive loss in device performances even in very low amounts. This finding is raising issues for large area manufacturing where organic semiconductors are commonly processed in ambient conditions. The cost of materials is also a critical when it comes to scale up solar cell production. If the best materials are achieving high PCE, it is crucial that these materials remain as low cost as possible thanks to simplified chemical structures and straightforward synthesis routes and purification steps. If a few simple and efficient polymers are currently emerging, we have been investigating a series of bio-inspired solution-processable compounds derivated from curcuminoids enabling one-pot, one-step synthetized organic semiconductors for OPV.Finally, large area OPV modules are currently facing two major challenges. (a) The need to be light activated which becomes difficult when the flexible product uses packaging sheets acting as UV filter to promote long lived devices. (b) The fast decay of efficiency within the first hours of usage under illumination; this so-called burn-in effect is still not fully understood and should be overcome. On these two issues, this communication will bring some fundamental understandings and guidelines for more efficient and stable OPV cells.