AZO/Ag/AZO anode for resonant cavity red, blue, and yellow organic light emitting diodes

Abstract

Indium tin oxide (ITO) is the transparent electrode of choice for organic light-emitting diodes (OLEDs). Replacing ITO for cost and performance reasons is a major drive across optoelectronics. In this work, we show that changing the transparent electrode on red, blue, and yellow OLEDs from ITO to a multilayer buffered aluminium zinc oxide/silver/aluminium zinc oxide (AZO/Ag/AZO) substantially enhances total output intensity, with better control of colour, its constancy, and intensity over the full exit hemisphere. The thin Ag containing layer induces a resonant cavity optical response of the complete device. This is tuned to the emission spectra of the emissive material while minimizing internally trapped light. A complete set of spectral intensity data is presented across the full exit hemisphere for each electrode type and each OLED colour. Emission zone modelling of output spectra at a wide range of exit angles to the normal was in excellent agreement with the experimental data and hence could, in principle, be used to check and adjust production settings. These multilayer transparent electrodes show significant potential for both eliminating indium from OLEDs and spectrally shaping the emission.

Robust Transparent and Conductive Gas Diffusion Multibarrier Based on Mg- and Al-Doped ZnO as Indium Tin Oxide-Free Electrodes for Organic Electronics

“…35 Therefore, in our OLED structure, the MoO 3 layer was added as a hole injection layer (HIL) for tuning the work function between the anode and polymer layers, resulting in an Ohmic contact with the polymer layers. 36 Therefore, from the results of measurements, although the ITO and MAM electrodes showed different work functions, the electrical characteristics of the PhOLEDs with ITO and MAM anodes were almost identical (Figure 6b,c).…”

High performance organic light-emitting diodes employing ITO-free and flexible TiOx/Ag/Al:ZnO electrodes

“…16 Gentle et al used a sputtered Al:ZnO/Ag/Al:ZnO TE and a solution-processed emitting layer, whereas as hole injection layer, a 10 nm-thick MoO 3 layer was evaporated on the TE. 17 The emitting layer consisted of spin-coated PDY-132 "Super Yellow" (from Merck, Germany). The OLEDs with the DMD (on glass substrate) showed 50% higher external quantum efficiency than reference devices on ITO.…”