Gravure printing inverted organic solar cells: The influence of ink properties on film quality and device performance

We investigate the relationship between processing parameters and the device performance of gravure printed organic solar cells. Ink viscosity, surface energy and surface roughness are studied to optimise the printing process. Surfactants, additives and surface modification by plasma cleaning are utilised to achieve homogeneous printing of multilayer OPV device architectures. It is found that use of high boiling point solvents with high solubilities leads to a desirable surface morphology. The use of a printed metal oxide electrode within the inverted structure leads to devices with lifetimes exceeding those of devices in standard structures without the need for encapsulation.