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Rapid Predictions of the Colour Purity of Luminescent Organic Molecules

Lookup NU author(s): Shawana Ahmad, Dr Julien EngORCiD, Professor Thomas Penfold



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Royal Society of Chemistry, 2022.

For re-use rights please refer to the publisher's terms and conditions.


Designing luminescent organic materials exhibiting narrowband emission is crucial for achieving high resolution and energy efficient organic light emitting diodes (OLEDs), but remains a significant challenge. Herein we establish the key factors determining the emission full-width at half-maximum (FWHM) of 27 organic functional molecules exhibiting emitting states of different characteristics, including π-π*, charge transfer and multiple-resonance. We demonstrate that the emission FWHM can be interpreted within the displaced harmonic oscillator model (DHO), meaning that predictions can be made using ground state frequency and excited state gradient calculations only. This eliminates the need for time consuming calculations of excited state geometries and Hessians. The DHO model not only makes it possible to predict emission FWHM, but also informs on the normal modes responsible for emission band broadening. In addition, quantum chemistry and rate calculations of three multiple-resonance type thermally activated delayed fluorescence (TADF) emitters demonstrates how the importance of direct intersystem crossing (ISC) can be increased when sulphur is used within the B-N framework. Overall, this work offers new perspectives for incorporating considerations of emission FWHM into rational molecular design and high-throughput screening procedures aiming to develop high efficiency luminescent organic materials.

Publication metadata

Author(s): Ahmad S, Eng J, Penfold TJ

Publication type: Article

Publication status: Published

Journal: Journal of Materials Chemistry C

Year: 2022

Volume: 10

Issue: 12

Pages: 4785-4794

Print publication date: 28/03/2022

Online publication date: 07/01/2022

Acceptance date: 07/01/2022

Date deposited: 07/01/2022

ISSN (print): 2050-7526

ISSN (electronic): 2050-7534

Publisher: Royal Society of Chemistry


DOI: 10.1039/D1TC04748E

ePrints DOI: 10.57711/xmky-pf32


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