Excited-state engineering enables efficient deep-blue light-emitting diodes exhibiting BT.2020 color gamut

DOI: 10.1002/adma.202313602

Authors: Rui-Zhi An (University of Science and Technology of China) , Yuqi Sun (University of Cambridge) , Hao‐yang Chen (University of Science and Technology of China) , Yuan Liu (Beijing Information Science & Technology University) , Alberto Privitera (University of Florence) , William K. Myers (University of Oxford) , Tanya K. Ronson (University of Cambridge) , Alexander J. Gillett (University of Cambridge) , Neil C. Greenham (University of Cambridge) , Lin-Song Cui (University of Science and Technology of China)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Advanced Materials

State: Published (Approved)
Published: April 2024
Diamond Proposal Number(s): 21497

Abstract: Organic luminescent materials that exhibit thermally activated delayed fluorescence (TADF) can convert non-emissive triplet excitons into emissive singlet states through a reverse intersystem crossing (RISC) process. Therefore, they have tremendous potential for applications in organic light-emitting diodes (OLEDs). However, with the development of ultra-high definition 4K/8K display technologies, designing efficient deep-blue TADF materials to achieve the Commission Internationale de l’Éclairage (CIE) coordinates fulfilling BT.2020 remains a significant challenge. Here, we propose an effective approach to design deep-blue TADF molecules based on hybrid long- and short-range charge-transfer by incorporation of multiple donor moieties into organoboron multiple resonance acceptors. The resulting TADF molecule exhibits deep-blue emission at 414 nm with a full width at half maximum (FWHM) of 29 nm, together with a thousand-fold increase in RISC rate. OLEDs based on our champion material achieved a record maximum external quantum efficiency (EQE) of 22.8% with CIE coordinates of (0.163, 0.046), approaching the coordinates of the BT.2020 blue standard. Moreover, TADF-assisted fluorescence devices employing our designed material as a sensitizer exhibited an exceptional EQE of 33.1%. Our work thus provides a blueprint for future development of efficient deep-blue TADF emitters, representing an important milestone towards meeting the blue color gamut standard of BT.2020.

Diamond Keywords: Organic Light Emitting Diodes (OLEDs)

Subject Areas: Materials, Chemistry, Medicine


Instruments: I19-Small Molecule Single Crystal Diffraction

Added On: 15/04/2024 08:52

Discipline Tags:

Physics Physical Chemistry Electronics Chemistry Materials Science

Technical Tags:

Diffraction Single Crystal X-ray Diffraction (SXRD)