Tuning the viscosity of halogen free bulk heterojunction inks for inkjet printed organic solar cells

摘要: For the solution processing of organic photovoltaics on an industrial scale, exclusion halogenated solvents is a necessity. However, limited solubility most semiconducting polymer/fullerene blends in non-halogenated results ink formulations with low viscosities which poses limitations to use roll-to-roll compatible deposition processes, such as inkjet printing. We propose add polystyrene rheological modifier increase viscosity bulk heterojunction (BHJ) inks. The printing and performance P3HT/PCBM photoactive layer inks are characterized function concentration three different molecular weights. Addition 1 wt% provided near two-fold gain viscosity, largest gains coming from polymer highest weight. this coincided greater viscoelastic behavior, reduced jetting Differences solvent compatibility polystyrene/P3HT/PCBM ternary blend resulted phase separation upon drying, whereby segregated layer-air interface form isolated domain or network like topology. Nevertheless, 1.7-fold dynamic was obtained for devices printed BHJ layers containing at expense 20% reduction OPV performance. improved good behavior achieved small additions demonstrates its potential overcome resulting typical polymers. These offer step forward industrialization effective technique functional electronics.