# High-Efficiency and Narrowband Green Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes Based on Two Diverse Boron Multi-Resonant Skeletons

## TL;DR

This paper introduces a new green light-emitting molecule that achieves high efficiency and narrowband emission for use in OLEDs.

## Contribution

The novel BNBO molecule is designed and synthesized, offering high efficiency and narrowband emission for green OLEDs.

## Key findings

- BNBO-based OLEDs exhibit a sharp emission peak at 508 nm with a full-width at half-maximum of 36 nm.
- The OLED achieves an external quantum efficiency of 24.3% and a power efficiency of 62.3 lm/W.
- BNBO's intramolecular charge transfer and multiple resonance characteristics enable efficient narrowband emission.

## Abstract

Up to now, highly efficient narrowband thermally activated delayed fluorescence (TADF) molecules constructed by oxygen-bridged boron with an enhancing multiple resonance (MR) effect have been in urgent demand for solid-state lighting and full-color displays. In this work, a novel MR-TADF molecule, BNBO, constructed by the oxygen-bridged boron unit and boron–nitrogen core skeleton as an electron-donating moiety, is successfully designed and synthesized via a facile one-step synthesis. Based on BNBO as an efficient green emitter, the organic light-emitting diode (OLED) shows a sharp emission peak of 508 nm with a full-width at half-maximum (FWHM) of 36 nm and realizes quite high peak efficiency values, including an external quantum efficiency (EQEmax) of 24.3% and a power efficiency (PEmax) of 62.3 lm/W. BNBO possesses the intramolecular charge transfer (ICT) property of donor-acceptor (D-A) materials and multiple resonance characteristics, which provide a simple strategy for narrowband oxygen–boron materials.