Diluted PEDOT:PSS for high-performance organic light-emitting devices with thermally activated delayed fluorescence emitters.

ABSTRACT

Poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOTPSS) is a widely used conductive polymer in organic light-emitting devices. However, its strong acidity and fluorescence quenching effect seriously affect the overall device performance. We report a cost-effective method to address the above concerns by diluting PEDOTPSS with deionized water, which effectively reduced the film thickness and the acidity. Therefore, the fluorescence quenching occurring at the interface was alleviated. Using the modified PEDOTPSS as the hole injection layer, the external quantum efficiency of the device could be effectively improved by a factor of 81%, reaching a considerably higher value of 23.5%, compared with the device consisting of the original PEDOTPSS solution used as received.