High quantum efficiencies of above 30% in blue phosphorescent organic light emitting diodes are achieved by using novel pyridoindole‐based bipolar host materials. A high quantum efficiency of 30.0% ...is obtained at 100 cd/m2 by using the new host materials.
Carbazole‐ and triazine‐derived thermally activated delayed fluorescent (TADF) emitters, with three donor units and an even distribution of the highest occupied molecular orbital, achieve high ...external quantum efficiencies of above 25% in blue and green TADF devices.
High quantum efficiency in solution and vacuum processed blue phosphorescent organic light emitting diodes are achieved using a new benzofuropyridine based bipolar host material. High quantum ...efficiencies of 18.0% and 23.0% are obtained in soluble and vacuum evaporable blue devices.
Blue thermally activated delayed fluorescent (TADF) emitters were developed by linking a donor moiety to a triazine core via the ortho-position of an aromatic moiety. Three phenylcarbazole ...derivatives with different substituents were incorporated into the 4,6-diphenyltriazine core to prepare the blue TADF emitters. The photophysical properties and device performance of the blue TADF emitters were investigated, and the blue TADF emitters with 3,6-dimethyl-9-phenylcarbazole as the donor moiety showed a high quantum efficiency of 14.7%.
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•Distorted ortho-linkage trazine core dopant materials were prepared.•CzTrz displayed delayed emission with a decay time of 3.9 μs at 300 K.•Sky-blue TADF OLEDs with a color purity of (0.15, 0.22) were developed.•The OLED shows a singlet-triplet energy gap less than 0.1 eV and high EQE of 14.7%.
Organic materials for organic electronic devices Lee, Chil Won; Kim, Oh Young; Lee, Jun Yeob
Journal of industrial and engineering chemistry (Seoul, Korea),
07/2014, Letnik:
20, Številka:
4
Journal Article
Recenzirano
In recent years, organic electronic devices which use organic materials as an active layer have gained considerable interest as light-emitting devices, energy converting devices and switching devices ...in many applications. In these organic electronic devices, the organic materials play a key role of managing the device performances and various organic materials have been developed to improve the device performances of organic electronic devices. In this paper, recent developments of organic electronic materials for organic light-emitting diodes and organic solar cells were reviewed.
Isosorbide is a bio-based renewable resource that has been utilized as a stiffness component in the synthesis of novel polymers. Modified isosorbide-based bis(2-hydroxyethyl)isosorbide (BHIS) has ...favorable structural features, such as fused bicyclic rings and a primary hydroxyl function with improved reactivity to polymerization when compared to isosorbide itself. Polyurethane series (PBH PU series) using polycarbonate diol (PCD) and bis(2-hydroxyethyl)isosorbide (BHIS) were polymerized through a simple, one-shot polymerization without a catalyst using various ratios of BHIS, PCD, and hexamethylene diisocyanate (HDI). The synthesized BHIS and PUs were characterized using proton nuclear magnetic resonance (
H-NMR), Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), and mechanical testing. To determine the feasibility of using these PUs as biomedical materials, we investigated the effects of their BHIS content on PBH PU series physical and mechanical properties. The PBH PU series has excellent elasticity, with a breaking strain ranging from 686.55 to 984.69% at a 33.26 to 63.87 MPa tensile stress. The material showed superb biocompatibility with its high adhesion and proliferation in the bone marrow cells. Given their outstanding mechanical properties and biocompatibility, the polymerized bio-based PUs can contribute toward various applications in the medical field.
A high triplet energy material derived from carbazole and pyridine, 9,9′-(5-(2-methylpyridin-3-yl)-1,3-phenylene)bis(9H-carbazole), was synthesized as the host material for blue and white ...phosphorescent organic light-emitting diodes. The 9,9′-(5-(2-methylpyridin-3-yl)-1,3-phenylene)bis(9H-carbazole) host showed a high triplet energy of 2.99 eV for efficient energy transfer to blue triplet emitter. High quantum efficiencies of 19.8% and 17.1% were achieved in blue and white phosphorescent organic light-emitting diodes using the 9,9′-(5-(2-methylpyridin-3-yl)-1,3-phenylene)bis(9H-carbazole) host material. In addition, the 9,9′-(5-(2-methylpyridin-3-yl)-1,3-phenylene)bis(9H-carbazole) based white phosphorescent organic light-emitting diodes showed good color stability.
•High triplet energy host material derived from carbazole and pyridine.•High quantum efficiency in blue and white phosphorescent organic light-emitting diodes.•Color stability in white phosphorescent organic light-emitting diodes.
A new bilayer electrospun nanofiber membranes consisting of a hydrophobic silver nanoparticle-based polyimide nanocomposite (Ag-PI) supporting layer and hydrophilic poly(vinyl alcohol) (PVA) barrier ...layer for oily wastewater treatment application has been presented. First of all, the Ag-PI electrospun nanofibrous supporting layer was fabricated through electrospinning and thermal treatment from polyamic acid containing silver carbamate. After that, the PVA electrospun nanofibrous barrier layer was constructed by electrospinning onto the supporting layer and chemical crosslinked. The silver nanoparticles were uniformly formed through thermal-reduction of silver carbamate in nanofiber, homogeneously. The constructed bilayer electrospun nanofiber membranes were characterized by the permeate flux, rejection rate, and antimicrobial activity of
Escherichia coli
and
Staphylococcus aureus
. It was found that they showed strong antimicrobial activity as well as a high flux and high rejection rate at low operating pressure.
A polyurethane series (PHEI-PU) was prepared via a one-shot bulk polymerization method using hexamethylene diisocyanate (HDI), polycarbonate diol (PCD), and isosorbide derivatives (ISBD) as chain ...extenders. The mechanical properties were evaluated using a universal testing machine (UTM), and the thermal properties were evaluated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The PHEI-PU series exhibited excellent mechanical properties with an average tensile strength of 44.71 MPa and an elongation at break of 190%. To verify the applicability of different proportions of PU as an electrode binder, PU and Ag flakes were mixed (30/70 wt%) and coated on PCT substrates, the electrodes were evaluated by four-point probe before and after 50% elongation, and the dispersion was evaluated by scanning electron microscopy (SEM). The electrical resistance change rate of PHEI-PU series was less than 20%, and a coating layer with well-dispersed silver flakes was confirmed even after stretching. Therefore, it exhibited excellent physical properties, heat resistance, and electrical resistance change rate, confirming its applicability as an electrode binder for in-mold coating.
A twist in the tail: The effect of varying the substitution position of dibenzofuran on its photophysical properties and organic light‐emitting diode device performance was systematically ...investigated by synthesizing three compounds with 2‐, 3‐ and 4‐substitution patterns (see scheme). The proper selection of substitution position can control the photophysical properties and performance of the materials.
