TRIPLET-TRIPLET ANNIHILATION LEADING TO DELAYED FLUORESCENCE EMISSION IN FILMS OF TWO COLUMNAR LIQUID CRYSTALS

Juliana Eccher; L. G. Franca (DR); UFSC and Durham University (UK); Paloma L. dos Santos; P. Pander (PD); Durham University (UK); Marília Gabriela Belarmino cabral; Desconhecido6208; Thiago Cazati; A. P. Monkman (Pq); University of Durham; H. Bock (Pq); CRPP

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Paper Title

TRIPLET-TRIPLET ANNIHILATION LEADING TO DELAYED FLUORESCENCE EMISSION IN FILMS OF TWO COLUMNAR LIQUID CRYSTALS

Authors

Juliana Eccher
L. G. Franca (DR); UFSC and Durham University (UK)
Paloma L. dos Santos
P. Pander (PD); Durham University (UK)
Marília Gabriela Belarmino cabral
Desconhecido6208
Thiago Cazati
A. P. Monkman (Pq); University of Durham
H. Bock (Pq); CRPP

Modality

Pôster

Subject area

Síntese e caracterização de materiais

Publishing Date

12/12/2023

Country of Publishing

Brasil

Language of Publishing

Inglês

Paper Page

https://www.even3.com.br/anais/workshop-do-ineo-2023/613293-triplet-triplet-annihilation-leading-to-delayed-fluorescence-emission-in-films-of-two-columnar-liquid-crystals

ISBN

978-65-272-0088-8

Keywords

olumnar Liquid Crystals, optical spectroscopy, triplet-triplet annihilation, delayed fluorescence

Summary

In recent years, the semiconducting liquid crystals (LCs) have been extensively applied in optoelectronic devices. Specially, columnar liquid crystals (ColLCs) formed by discotic shape molecules which stacked one on top of the other in columnar superstructures due to strong p-p interactions [1]. Columnar liquid crystals based on perylene core are particularly interesting as they are easily functionalized, are thermally and chemically stable, and have excellent optical properties [2]. OLED efficiency is limited due to spin statistics. Thus, the design of molecules exhibiting efficient phosphorescence, thermally activated delayed fluorescence (TADF), or delayed fluorescence (DF) from triplet-triplet annihilation (TTA) has emerged as a strategy to harvest these dark triplet states [3]. In this work, we combined two perylene-based ColLCs to investigate their photophysical properties and evaluate their potential application in OLEDs. To our surprise, we observed a first example of a ColLC mesogen exhibiting DF in solution. The strong concentration dependence indicates that it originates by a TTA mechanism. In the condensed state, surprisingly, DF is only observed in blend films, which is to our knowledge the first time that DF by TTA is observed in the ColLC state. Combination of the two molecules in blends yields TTA from ColLC-A dimers fuelled by the triplet population on ColLC-B dimers. Likewise, the external heavy atom effect of a bromopolymer matrix fuels emission from ColLC-A. The observation of DF in LC films, where molecules can be uniformly oriented by annealing, opens up the possibility to use such materials into OLEDs to enhance light outcoupling as well as charge and exciton transport [4]. The authors thank CNPq, CAPES/PROCAD, FAPESC, INCT/INEO, CAPES-COFECUB Project and OCTA Project. [1] S. Kumar, Chem. Soc. Rev. 35, 83–109 (2006) [2] M. Matussek, et al., Dyes and Pigments 159, 590–599 (2018) [3] Y.Luo and H. Aziz, Adv. Funct. Mater. 20 (8), 1285–1293 (2010) [4] L. G. Franca, et al., ACS Appl. Electron. Mater. 4, 3486-3494 (2022)

Title of the Event: Workshop do INEO 2023
City of the Event: Nazaré Paulista
Title of the Proceedings of the event: Anais do Workshop INEO 2023
Name of the Publisher: Even3
Means of Dissemination: Meio Digital

How to cite

ECCHER, Juliana et al.. TRIPLET-TRIPLET ANNIHILATION LEADING TO DELAYED FLUORESCENCE EMISSION IN FILMS OF TWO COLUMNAR LIQUID CRYSTALS.. In: Anais do workshop INEO 2023. Anais...Nazaré Paulista(SP) Hotel Estância Atibainha, 2023. Available in: https//www.even3.com.br/anais/workshop-do-ineo-2023/613293-TRIPLET-TRIPLET-ANNIHILATION-LEADING-TO-DELAYED-FLUORESCENCE-EMISSION-IN-FILMS-OF-TWO-COLUMNAR-LIQUID-CRYSTALS. Access in: 20/05/2025