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Synthesis and photoluminescent properties of geometrically hindered cis-tris(diphenylaminofluorene) as precursors to light-emitting devices.

ABSTRACT: A novel highly luminescent tris-fluorenyl ring-interconnected chromophore tris(DPAF-C9) was synthesized using a C3 symmetrical triaminobenzene core as the synthon. This structure bears three light-harvesting 2-diphenylamino-9,9-dialkylfluorenyl (DPAF) ring moieties with each attached by two branched 3',5',5'-trimethylhexyl (C9) arms. A major stereoisomer was chromatographically isolated and characterized to possess a 3D structural configuration of cis-conformer in a cup-form. Molecular calculation at B3LYP/6-31G* level revealed the unexpected stability of this cis-cup-conformer of tris(DPAF-C9) better than that of the stereoisomer in a propeller-form and the trans-conformer. The structural geometry is proposed to be capable of minimizing the aggregation related self-quenching effect in the condensed phase. Fluorescence emission wavelength of tris(DPAF-C9) was found to be in a close range to that of PVK that led to its potential uses as the secondary blue hole-transporting material for enhancing the device property toward the modulation of PLED performance.

SUBMITTER: Kang NG

PROVIDER: S-EPMC6272756 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

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Synthesis and photoluminescent properties of geometrically hindered cis-tris(diphenylaminofluorene) as precursors to light-emitting devices.

Kang Nam-Goo NG Kokubo Ken K Jeon Seaho S Wang Min M Lee Chang-Lyoul CL Canteenwala Taizoon T Tan Loon-Seng LS Chiang Long Y LY

Molecules (Basel, Switzerland) 20150313 3

A novel highly luminescent tris-fluorenyl ring-interconnected chromophore tris(DPAF-C9) was synthesized using a C3 symmetrical triaminobenzene core as the synthon. This structure bears three light-harvesting 2-diphenylamino-9,9-dialkylfluorenyl (DPAF) ring moieties with each attached by two branched 3',5',5'-trimethylhexyl (C9) arms. A major stereoisomer was chromatographically isolated and characterized to possess a 3D structural configuration of cis-conformer in a cup-form. Molecular calculati ...[more]

PMID: 25781068

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Project description:A new series of hyperbranched polymers consisting of fluorene-alt-carbazole as the branches and the three-dimensional-structured spiro[3.3]heptane-2,6-dispirofluorene (SDF) as the core were designed and synthesized by one-pot Suzuki coupling polycondensation. A phosphor group with broad full width at half maximum (FWHM) bis(1-phenyl-isoquinoline)(acetylacetonato)iridium(iii) (Ir(Brpiq)2acac, 0.08 mol%) as the red-light emitting unit and bis(2-(4-bromophenyl)-1-[6-(9-carbazolyl)hexyl]-imidazole)(2-(5-(4-fluorinated phenyl)-1,3,4-triazole)pyridine)iridium(iii) ((CzhBrPI)2Ir(fpptz)) as the green-light emitting unit were introduced into the backbones to obtain sunlight-style white-light emission by adjusting the feeding ratios of (CzhBrPI)2Ir(fpptz) (0.08 to 0.32 mol%). The results indicate the synthesized polymers show high thermal stabilities and good amorphous film morphology because of the hyperbranched structures. Besides, the lowest unoccupied molecular orbital (LUMO) levels of polymers were reduced and the electron injection was improved because of excellent electron-transporting ability of the triazole unit in the green group. The hyperbranched structures can effectively suppress the polymers' chain distortion and aggregation, and promote the incomplete Förster resonance energy transfer (FRET) efficiency from fluorene-alt-carbazole segments to Ir complex units. As a result, the devices with hyperbranched polymer light-emitting layers realize white light emission, and the optimized device also exhibits good electroluminescent (EL) performance with Commission Internationale de l'Eclairage (CIE) coordinates at (0.32, 0.31), a maximum luminance of 9054 cd m-2, a maximum current efficiency of 3.59 cd A-1 and a maximum Color Rendering Index (CRI) of 91. The hyperbranched polymers based on fluorene-alt-carbazole branches and a SDF core and high-efficiency phosphor groups with broad full width at half maximum are attractive candidates for sunlight-style white polymer light-emitting device.

Dataset Information

Synthesis and photoluminescent properties of geometrically hindered cis-tris(diphenylaminofluorene) as precursors to light-emitting devices.

Publications

Synthesis and photoluminescent properties of geometrically hindered cis-tris(diphenylaminofluorene) as precursors to light-emitting devices.

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