The first aggregation-induced emission fluorophore as a solution processed host material in hybrid white organic light-emitting diodes

Abstract

A judicious structure design of bis(3,5-di(9H-carbazol-9-yl)phenyl)amine (CzPA) and 1,1,2,2-tetraphenylethene (TPE) hybrid generates the first aggregation-induced emission (AIE) fluorophore, CzPATPE, as a solution processed host material in hybrid white organic light-emitting diode (OLED). Small molecule CzPATPE has been verified for the amorphous characteristics by a featureless halo in powder X-ray diffraction spectra and a glass transition temperature as high as 180 o C. Fluorescence images indicate that a homogenous thin film of CzPATPE is obtained from a solution drop-casting process. Solution (THF/water) fluorescence spectroscopy study clearly demonstrates a typical AIE property of CzPATPE. Whereas CzPATPE is virtually non-emissive in common organic solvents, thin film photoluminescence (PL) spectroscopy shows that CzPATPE has a strong sky blue emission around 495 nm with a relatively wide full width at half maximum (FWHM) about 95 nm and a reasonable PL quantum yield of 40%. Low temperature time-gated PL spectroscopy identifies CzPATPE's triplet optical gap energy ET ~2.05-2.16 eV, which is barely enough for phosphorescence dopant, tris(2phenylquinoline) iridium (III) (Ir(2-phq)3) (ET ~2.13 eV). CzPATPE is solution processable to be a sky blue emissive host material for orange dopant in the hybrid white OLED, ITO/PEDOT:PSS (65 nm)/CzPATPE:Ir(2-phq)3(99.9:0.1,~40 nm)/TmPyPB(50 nm)/CsF (2 nm)/Al(100 nm). This AIE hybrid white OLED displays white electroluminescence (EL) with colour chromaticity of CIEx,y(0.36, 0.43). Although the maximum EL efficiency is modest 3.4 cd/A or 1.8 lm/W, the white OLED has a colour rendering index (CRI) of 72, which is unusually high considering the orange dopant and two-colour white feature. We attribute such CRI to the relatively large FWHM of CzPATPE.

An optical and electrical study of full thermally activated delayed fluorescent white organic light-emitting diodes

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Multifunctional nanogel engineering with redox-responsive and AIEgen features for the targeted delivery of doxorubicin hydrochloride with enhanced antitumor efficiency and real-time intracellular imaging

“…AIE molecule TPENH 2 was prepared according to previous reports [46]. In brief, a certain amount of zinc powder was added to a 100 ml round-bottom flask containing 40 ml THF.…”

Solution‐processed Small Molecular Materials: Bulk Heterojunction Organic Photovoltaic Materials, Host Materials for Phosphorescence Organic Light‐emitting Diodes, and Nondopant Thermally Activated Delayed Fluorescence Materials

“…Lee et al . reported 89 for a special application, namely solution‐processed hybrid white OLED . In their report, 89 was used as the host material for Ir(2‐phq) 3 , an orange‐red phosphorescence dopant.…”