Title:  Highly Efficient Organic Light-Emitting Diodes from Thermally Activated Delayed Fluorescence

Committee: 

Dr. Kippelen, Advisor  

Dr. Cai, Chair

Dr. Brand

Abstract:

The objective of the proposed research is to study organic light-emitting diodes (OLEDs) incorporating emitters showing thermally activated delayed fluorescence (TADF) with the goal to achieve high performance. TADF is caused by the thermal activation of long-lived triplet excited states to form fluorescent singlet excited states as a strategy to have all excited states formed in electroluminescent devices contribute to light emission. This interest is motivated in part by finding alternatives to electrophosphorescent materials that contain heavy noble metals that present inherent limitations associated with their use, such as toxicity for some biological applications.This proposal reports on recent progress in the design, synthesis and characterization of new TADF molecules and their use in OLEDs. The results show that devices with optimized external quantum efficiency of 22.8% at a luminance of 1,000 cd/m2 are obtained at high concentrations of TADF emitters (up to 50 wt.%), challenging current prescriptions for device optimization. The research demonstrates that TADF emitters are promising material for future OLEDs.