LAUSR

Conducting polymer/metal oxide heterostructures have been commonly used in solution-processed tandem organic optoelectronic devices as charge generation layer (CGL) or charge recombination layer. However, the underlying working mechanism remains unexplored. We optimize the preparation of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)/zinc oxide (ZnO) CGL and report that the configurations and compositions of the interconnects significantly affect the performance of light-emitting devices. Two-unit and in particular the first reported three-unit solution-processed tandem polymer light-emitting devices show the luminance efficiency matching the total luminance efficiency of the constituent two and three light-emitting units, respectively. Current–voltage and capacitance–voltage measurements on the devices with various interconnects indicate that charges are generated at the PEDOT:PSS/ZnO interface. CGL-generated current can be described with the Richardson–Schottky thermal emission mode...