High-Efficiency Transparent Small-Molecule Organic Light-Emitting Devices Adopting Laminated Transparent Top Electrodes

Abstract

We demonstrate a highly efficient transparent small-molecule OLED with laminated top transparent electrode. This was made possible via the aid of the transparent conductive adhesive based on the conducting polymer PEDOT:PSS. With use of small-molecule materials and efficient phosphorescent emitters, rather high external quantum efficiency and current efficiency of up to (11.4%, 43.1 cd/A), comparable to the non-transparent non-laminated reference device and much higher than those in previously reported OLEDs using laminated top electrodes, were obtained. The transparent OLEDs exhibited rather balanced EL intensities and spectra from both sides of the devices, a broad optical transmission band, and a high optical transmittance of up to 77%. It provides a simple and yet effective approach for fabrication of efficient transparent OLEDs. It is not only useful for devices on rigid substrates by also can be extended to flexible devices or even roll-to-roll processes of such devices in future.