Project description
Organic narrowband emitters for highly stable blue OLEDs
Organic light-emitting diodes (OLEDs) can achieve 100 % internal quantum efficiency using thermally activated delayed fluorescence (TADF) materials. However, these materials often exhibit broad emission spectra. A subclass of TADF materials, known as multi-resonant TADF (MR-TADF) emitters, has shown promise for narrow emission and high colour purity. Despite this, MR-TADF emitters generally have weaker device stability and shorter operational lifetime. The EU-funded HONESTY project aims to develop organic narrowband TADF emitters for highly stable blue OLEDs with reduced efficiency roll-off. Using a rational design approach, the project targets a high reverse intersystem crossing rate to achieve long lifetimes and improved stability. One of the designs features a rigid tellurium-based acceptor decorated with high triplet energy donors.
Objective
Constricted by electron spin statistics, the maximum internal quantum efficiency of 100% can be achieved in organic light-emitting diodes (OLEDs) by utilizing purely organic thermally activated delayed fluorescence (TADF) materials. However, due to strong charge transfer, they exhibit broad emission with a full-width-at-half maximum (FWHM) > 70 nm. Recently, multiresonant TADF (MR-TADF) emitters, a sub-class of TADF materials based on alternating boron and nitrogen atoms embedded into polycyclic aromatic hydrocarbon scaffolds, are attracting much interest in OLEDs. Their key attributes include a narrow FWHM, high photoluminescence quantum yield, and unprecedented color purity. Even though these MR materials have advantages in color purity over conventional TADF materials, their device stability is weak and results in a poor operational lifetime (LT) due to the large singlet-triplet energy gap, delayed fluorescence lifetime, and too slow rate of reverse intersystem crossing (RISC). Especially, narrowband blue OLEDs LT (<100h) is still inferior to the conventional TADF OLEDs. The HONESTY project seeks to address the above issues by rationally designing organic narrowband novel TADF emitters. Our designs comprised four types (a combination of boron and non-boron) targeting a high RISC rate, leading to highly stable narrowband blue OLEDs with long LT. Among the four types, one design includes yet unexplored rigid tellurium-based acceptor decorated with high triplet energy donors, which is keen for new TADF scaffolds. The rigidity of all chemical components with slightly twisted confirmation and aryl groups on donors will work coherently to furnish highly stable OLEDs with suppressed efficiency roll-off, improved device stability, and long LT. Overall, the HONESTY proposal is anticipated to provide a breakthrough in stable blue narrowband TADF-OLEDs with the supervision of Karolis Kazlauskas, a physics expert in stable OLEDs working at Vilnius University, Lithuania.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- engineering and technologymaterials engineeringcolors
- natural scienceschemical sciencesorganic chemistryhydrocarbons
- natural scienceschemical sciencesinorganic chemistrymetalloids
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Programme(s)
Funding Scheme
HORIZON-TMA-MSCA-PF-EF - HORIZON TMA MSCA Postdoctoral Fellowships - European FellowshipsCoordinator
01513 Vilnius
Lithuania