P‐116: TADF OLED Emission Zone and Stability Analysis with Water Exposure to Different Layers During Deposition

Abstract

Reliable devices are essential for the commercialization of OLED technology. OLED materials are notorious for their sensitivity to various substances such as water. For thermally activated delayed emission (TADF) OLEDs, which layers are most water‐sensitive is unknown. Work towards understanding how water affects OLED performance is shown. Surprisingly, it is shown that the water effect on the emission layer is negligible compared to other layers in this stack. The emission zone is measured for fresh and degraded OLEDs deposited under different water partial pressures. Using a novel highly sensitive measurement method, a shift to the anode side was observed.

A Thermally Activated Delayed Fluorescence Green OLED with 4500 h Lifetime and 20% External Quantum Efficiency by Optimizing the Emission Zone using a Single‐Emission Spectrum Technique

“…[ 44 ] Regarding the stack layer thicknesses, all thicknesses were taken from an established stack in the literature. [ 5 ] Devices were deposited under low water pressure of 10 −7 Pa. [ 45 ] Masks enabled separate deposition onto the four quarters of the substrate, for each layer deposition stage, allowing four separate‐structure devices per deposition run.…”