Preorganization of Nanostructured Inks for Roll-to-Roll-Coated Polymer Solar Cells

The challenges associated with obtaining the desired nanomorphology of the active layer in polymer solar cells were addressed through preparation of conjugated polymer chains grown from the surface of seed nanoparticles with a well-defined size. Poly-3-hexylthiophene (P3HT) was thus polymerized using a quasi-living chain polymerization method initiated by surface-modified silica nanoparticles. The nanoparticles with a silica core and a P3HT-corona exhibited excellent solubility and optical properties similar to native P3HT. Upon mixing with phenyl-C61-butyric acid methyl ester in solution, a preorganized ink was obtained that was used to make polymer solar cell modules in a full roll-to-roll coating and printing process operating in ambient air. The polymer solar cells were thus prepared by a mixture of slot die and flat-bed screen printing. Various polymer solar cell modules were prepared ranging from single cells to two, three, and eight serially connected cells. The power conversion efficiency for the polymer solar cell modules were in the range of 0.8%-1.2% with an active area of up to 120 cm.