Toward High Efficiency Water Processed Organic Photovoltaics: Controlling the Nanoparticle Morphology with Surface Energies

摘要

Here efficient organic photovoltaic devices fabricated from water-basedcolloidal dispersions with donor:acceptor composite nanoparticles achievingup to 9.98% power conversion efficiency (PCE) are reported. This highefficiency for water processed organic solar cells is attributed to morphologycontrol by surface energy matching between the donor and the acceptormaterials. Indeed, due to a low interfacial energy between donor and theacceptor, no large phase separation occurs during the nanoparticle formationprocess as well as upon thermal annealing. Indeed, synchrotron-basedscanning transmission X-ray microscopy reveals that the internal morphologyof composite nanoparticles is intermixed as well as the active layermorphology after thermal treatment. The PCE of this system reaches 85% thatof devices prepared from chlorinated solvent. The gap between water-basedinks and organic solvent-based inks gets narrower, which is promising for thedevelopment of eco-friendly processing and fabrication of organicphotovoltaics.