Pyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs

Three novel small organic heterocyclic compounds: 2-(1,2-diphenyl)-1H-benzimidazole-7-tert-butylpyrene (compound A), 1,3-di(1,2-diphenyl)-1H-benzimidazole-7-tert-butylpyrene (compound B)...

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Autores principales:	Thenahandi Prasanthi Deepthika De Silva, Sang Gil Youm, Frank R. Fronczek, Girija Sahasrabudhe, Evgueni E. Nesterov, Isiah M. Warner
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	OLED benzimidazole pyrene electroluminescence optoelectronic applications Organic chemistry QD241-441
Acceso en línea:	https://doaj.org/article/364d6044bddb4e23ae4394eb7aacdb9e
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spelling	oai:doaj.org-article:364d6044bddb4e23ae4394eb7aacdb9e2021-11-11T18:31:07ZPyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs10.3390/molecules262165231420-3049https://doaj.org/article/364d6044bddb4e23ae4394eb7aacdb9e2021-10-01T00:00:00Zhttps://www.mdpi.com/1420-3049/26/21/6523https://doaj.org/toc/1420-3049Three novel small organic heterocyclic compounds: 2-(1,2-diphenyl)-1<i>H</i>-benzimidazole-7-<i>tert</i>-butylpyrene (compound <b>A</b>), 1,3-di(1,2-diphenyl)-1<i>H</i>-benzimidazole-7-<i>tert</i>-butylpyrene (compound <b>B</b>), and 1,3,6,8-tetra(1,2-diphenyl)-1<i>H</i>-benzimidazolepyrene (compound <b>C</b>) were synthesized and characterized for possible applications as blue OLED emitters. The specific molecular design targeted decreasing intermolecular aggregation and disrupting crystallinity in the solid-state, in order to reduce dye aggregation, and thus obtain efficient pure blue photo- and electroluminescence. Accordingly, the new compounds displayed reasonably high spectral purity in both solution- and solid-states with average CIE coordinates of (0.160 ± 0.005, 0.029 ± 0.009) in solution and (0.152 ± 0.007, 0.126 ± 0.005) in solid-state. These compounds showed a systematic decrease in degree of crystallinity and intermolecular aggregation due to increasing steric hindrance, as revealed using powder X-ray diffraction analysis and spectroscopic studies. An organic light-emitting diode (OLED) prototype fabricated using compound <b>B</b> as the non-doped emissive layer displayed an external quantum efficiency (EQE) of 0.35 (±0.04)% and luminance 100 (±6) cd m<sup>−2</sup> at 5.5 V with an essentially pure blue electroluminescence corresponding to CIE coordinates of (0.1482, 0.1300). The highest EQE observed from this OLED prototype was 4.3 (±0.3)% at 3.5 V, and the highest luminance of 290 (±10) cd m<sup>−2</sup> at 7.5 V. These values were found comparable to characteristics of the best pure blue OLED devices based on simple fluorescent small-molecule organic chromophores.Thenahandi Prasanthi Deepthika De SilvaSang Gil YoumFrank R. FronczekGirija SahasrabudheEvgueni E. NesterovIsiah M. WarnerMDPI AGarticleOLEDbenzimidazolepyreneelectroluminescenceoptoelectronic applicationsOrganic chemistryQD241-441ENMolecules, Vol 26, Iss 6523, p 6523 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	OLED benzimidazole pyrene electroluminescence optoelectronic applications Organic chemistry QD241-441
spellingShingle	OLED benzimidazole pyrene electroluminescence optoelectronic applications Organic chemistry QD241-441 Thenahandi Prasanthi Deepthika De Silva Sang Gil Youm Frank R. Fronczek Girija Sahasrabudhe Evgueni E. Nesterov Isiah M. Warner Pyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs
description	Three novel small organic heterocyclic compounds: 2-(1,2-diphenyl)-1<i>H</i>-benzimidazole-7-<i>tert</i>-butylpyrene (compound <b>A</b>), 1,3-di(1,2-diphenyl)-1<i>H</i>-benzimidazole-7-<i>tert</i>-butylpyrene (compound <b>B</b>), and 1,3,6,8-tetra(1,2-diphenyl)-1<i>H</i>-benzimidazolepyrene (compound <b>C</b>) were synthesized and characterized for possible applications as blue OLED emitters. The specific molecular design targeted decreasing intermolecular aggregation and disrupting crystallinity in the solid-state, in order to reduce dye aggregation, and thus obtain efficient pure blue photo- and electroluminescence. Accordingly, the new compounds displayed reasonably high spectral purity in both solution- and solid-states with average CIE coordinates of (0.160 ± 0.005, 0.029 ± 0.009) in solution and (0.152 ± 0.007, 0.126 ± 0.005) in solid-state. These compounds showed a systematic decrease in degree of crystallinity and intermolecular aggregation due to increasing steric hindrance, as revealed using powder X-ray diffraction analysis and spectroscopic studies. An organic light-emitting diode (OLED) prototype fabricated using compound <b>B</b> as the non-doped emissive layer displayed an external quantum efficiency (EQE) of 0.35 (±0.04)% and luminance 100 (±6) cd m<sup>−2</sup> at 5.5 V with an essentially pure blue electroluminescence corresponding to CIE coordinates of (0.1482, 0.1300). The highest EQE observed from this OLED prototype was 4.3 (±0.3)% at 3.5 V, and the highest luminance of 290 (±10) cd m<sup>−2</sup> at 7.5 V. These values were found comparable to characteristics of the best pure blue OLED devices based on simple fluorescent small-molecule organic chromophores.
format	article
author	Thenahandi Prasanthi Deepthika De Silva Sang Gil Youm Frank R. Fronczek Girija Sahasrabudhe Evgueni E. Nesterov Isiah M. Warner
author_facet	Thenahandi Prasanthi Deepthika De Silva Sang Gil Youm Frank R. Fronczek Girija Sahasrabudhe Evgueni E. Nesterov Isiah M. Warner
author_sort	Thenahandi Prasanthi Deepthika De Silva
title	Pyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs
title_short	Pyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs
title_full	Pyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs
title_fullStr	Pyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs
title_full_unstemmed	Pyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs
title_sort	pyrene-benzimidazole derivatives as novel blue emitters for oleds
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/364d6044bddb4e23ae4394eb7aacdb9e
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Pyrene-Benzimidazole Derivatives as Novel Blue Emitters for OLEDs

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