Metal-thermally activated delayed fluorescence materials
Grant Data
Project Title
Metal-thermally activated delayed fluorescence materials
Principal Investigator
Professor Che, Chi Ming
(Principal Investigator (PI))
Duration
36
Start Date
2020-07-01
Amount
10661276
Conference Title
Metal-thermally activated delayed fluorescence materials
Keywords
activate, delayed fluorescence materials, Metal-thermally
Discipline
Electronics
Panel
Physical Sciences (P)
HKU Project Code
PRP/071/19FX
Grant Type
Partnership Research Programme (PRP)
Funding Year
2020
Status
On-going
Objectives
Thermally activated delay fluorescence (TADF)-OLED is an emerging new generation of OLED technology based on organic or metal-organic emitter featuring a modest S1-T1 energy separation and high radiative decay rate. Latest TADF-OLEDs have attained comparable efficiencies with the best iridium- and platinum-based phosphorescence OLEDs in red, green and blue colors essential for a full-color display. A fundamental challenge facing organic TADF-OLED is the device stability related to the lifetime of the triplet excitons; in the absence of efficient T1-S0 internal conversion channel, the residual long-lived triplet excitons in organic-TADF devices would result in irreversible chemical changes at high luminance. Metal-TADF emitters are superior to pure organic TADF emitters as the metal-induced spin-orbital coupling would facilitate intersystem crossing, leading to a short lifetime of triplet excitons. Literature examples of copper(I)- and gold(I)-TADF emitters, however, have limited chemical/electrochemical stability. Built upon our experience in developing metal-OLED emitters, in this project we plan to collaborate with Aglaia to develop gold(III) and tungsten(VI) based TADF emitters which are conceived to be more robust as a result of high metal charge and strong metal-ligand bond of 3rd-row transition metal. The large spin-orbit coupling constants and stable T1 states are advantageous for efficient reverse intersystem crossing and hence TADF. Besides, the development of tungsten and gold based OLED technologies are of strategic importance considering the global abundance and regional distribution of the noble metals; tungsten is an earth-abundant metal with China being the largest producer while gold reserve in China is second richest in the world.