Transfer printing of organic light-emitting diodes

A novel vacuum-free manner to fabricate thin films via transfer printing (TP), which relies on the adhesion between different interfaces, is presented and explained. For solution-processed organic light-emitting diodes (OLEDs), it is very challenging to fabricate the multilayered structures that are typically required of high-performance devices, due to interfacial mixing. Although orthogonal spin-coating provides an alternative strategy to fabricate the multilayered OLEDs, it is vital to select the solvents and cross-linkable materials to prevent the underneath layer from being dissolved. In contrast, a uniform film could be solution-processed on a mother or donor substrate and then transfer and printed to a target substrate or film by simply controlling the interfacial adhesion. This dramatically eases the design of materials and devices. This chapter describes the principles of TP and its applications for OLEDs.