Reverse gravure coating for roll-to-roll production of organic photovoltaics

Abstract

Reverse gravure (RG) coating is reported here as an alternate film deposition method for potential large scale roll-to-roll production of organic photovoltaic devices (OPVs). The basic working principles of RG coating are shown and compared to the more well-known gravure printing. Gravure printing is similar to RG coating from a process point of view, but the films produced using each method are very different to each other. An optical thickness measurement system was developed and used to monitor film thickness variation of RG coated photo-active layers with various coating parameters in situ in the roll-to-roll process. Partially and fully printed OPV modules were fabricated using, primarily, the roll-to-roll RG coating process and devices showed 2.1% and 1.5% power conversion efficiencies, respectively.