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Background: Benzo[b]furan derivatives are oxygen-containing heterocyclic compounds consisting of fused benzene and furan rings and are present in a large number of natural and non-natural compounds. This class of compounds has a wide spectrum of biological activities, such as antiarrhythmic, anticancer, inflammatory, antioxidant, antimicrobial, and antiviral. Furthermore, benzo[b]furan derivatives have also been applied in various areas, such as organic electroluminescence device materials and organic dyes, photosensitizing material, organic synthesis as building blocks or intermediates. : Because of a broad range of applicability, the synthesis of benzo[b]furan derivative has drawn great attention of chemists and many studies on the synthesis of this class of compounds have been reported recently. This review will give an overview of benzo[b]furan preparation based on studies dating back to the year 2012. Objective: In this review, recent development in the synthesis of benzo[b]furans are discussed. There has been increasingly new methodologies for the construction of benzo[b]furans skeleton to improve efficiency or develop environmentally friendly procedures. In some studies, reaction mechanisms were also outlined. Conclusion: Many methods for the synthesis of benzo[b]furans have been reported recently. Most of them involve cyclization or cycloisomerization processes. Unquestionably, more imaginative strategies for the construction of benzo[b]furan skeleton will be established in the near future. Application of known methods to natural products or drug synthesis, on industrial scale for the synthesis of economically or medicinally important benzo[ b]furans will probably be paid attention to.

In this study, we report an investigation of the fabrication and characterization of film-based organic electroluminescence (OEL). The film-based OEL was fabricated by deposition of 4,4′,4′′-tris[2-naphthyl(phenyl)amino] triphenylamine (2T-NATA), tris (8-hydroxyquinolinato) aluminium (Alq3), LiF, and Al on the polyethylene naphthalate (PEN) film. The film-based OEL indicates the green emission, which is due to the fluorescence of Alq3, and highest luminance reached 4408 cd m-2. Additionally, it was also confirmed that film-based OEL indicated the green emission in the curved state. From these results, we concluded that the film-based OEL functioned as a flexible OEL.

In this study, we report an investigation of the fabrication and characterization of film-based organic electroluminescence (OEL). The film-based OEL was fabricated by deposition of 4,4′,4′′-tris[2-naphthyl(phenyl)amino] triphenylamine (2T-NATA), tris (8-hydroxyquinolinato) aluminium (Alq3), LiF, and Al on the polyethylene naphthalate (PEN) film. The film-based OEL indicates the green emission, which is due to the fluorescence of Alq3, and highest luminance reached 4408 cd m-2. Additionally, it was also confirmed that film-based OEL indicated the green emission in the curved state. From these results, we concluded that the film-based OEL functioned as a flexible OEL.

Comparing rigid inorganic layer, polymeric semiconducting gate layer exhibits superior flexibility as well as efficient carrier manipulation in high frequency AC cycles. Mechanism of the carrier manipulation at the gate in forward and reversed bias of AC cycle is studied. The flexible PET-based AC-OEL device with poly[(9,9-bis(3'-((N,N-dimethyl)-Nethylammonium)- propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN-Br) gate shows a stable electroluminescent performance in frequency sweep with a color rendering index (CRI) over 81 at 2800K color temperature.

The first application of electroluminescence detected electron spin resonance technique on electroluminescent thermally activated delayed fluorescence (TADF) devices is shown. It indubitably proves the involvement of spins in the emergence of TADF electroluminescence and reveals the temperature dependency of such spin-dependent processes on bilayer devices that consist of two different material systems.

A novel iron-catalyzed intramolecular ring-closing C–H amination reaction of o-phenylenediamines was developed, affording the corresponding 2,7-disubstituted 5,10-diaryl-5,10-dihydrophenazines in acceptable yields. The reaction proceeded via the in-situ generation of the magnesium amides of the starting secondary amines in the presence of a catalytic amount of an iron salt and a stoichiometric amount of 1,2-dibromoethane as the terminal oxidant. The substituted dihydrophenazine derivatives can potentially be used as hole-injection materials in organic electroluminescence (OEL) devices and also offer scaffolds for further synthetic elaborations of OEL materials.

Purpose. To determine whether organic electroluminescence (OLED) screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs).Method. Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA) screen and on an OLED (17 inches, 320 × 230 mm, PVM-1741, Sony, Tokyo, Japan) screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years).Results. The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0 msec on the cathode-ray tube (CRT) screen and 0.5 msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens.Conclusion. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account.

To improve the performance of blue fluorescent and green phosphorescent organic light-emitting diode devices, Merck developed novel green phosphorescent host and electron-transporting materials. The newly developed electron-transporting material improves the external quantum efficiency of blue fluorescent devices up to 8.7%, with an excellent lifetime. In combination with the newly developed host materials, the efficiency of green phosphorescent devices can be improved by a factor of 1.7, and the lifetime by a factor of 7.

This review paper describes the present status of passivation films with organic/Inorganic multilayer structure on flexible organic film substrate designed for electronic devices such as organic light emitting diode (OLED). Passivation film of SiNx/CN:H multilayer showed an excellent barrier properties for water and oxygen and strongly suppressed an appearance of dark spots on OLED surface during operation. The luminous efficiency of flexible OLED thus formed with passivation films revealed to be equivalent to that on glass substrate encapsulated by can. substrate.

We report the synthesis of a red light‐emitting and photopolymerizable smectic liquid crystal (reactive mesogen). We investigate the suitability of polymer networks formed from smectic reactive mesogens for use in organic light‐emitting diodes (OLEDs). The use of mixtures of smectic reactive mesogens is shown to lower the processing temperature for the fabrication of OLEDs to room temperature. We also report efficient energy transfer from a nematic polymer network host to a smectic light‐emitting dopant and polarized emission from a polymer network formed from an aligned smectic reactive mesogen.

Organic phosphors have demanded the attention of the organic electroluminescence community because they enable efficiencies quadruple that of fluorescent materials. In this work, we review the categories of organic phosphors: lanthanide complexes, organic phosphors and metal-organic complexes. The characteristics necessary for efficient phosphor- escence are considered and conclusions are drawn as to the most promising materials.

Six homopolymeres derives de l'entite emettrice naphtalimide ont ete synthetises et caracterises par absorption UV-visible et photoluminescence. Ces polymeres se distinguent soit par leur chaine principale (polymethylmethacrylate ou polystyrene), soit par le substituant de l'azote de l'imide. Tous presentent la propriete d'electroluminescer dans le vert. Associe au polyvinylcarbazole dans une structure bicouche, l'un d'entre eux emet jusqu'a 7100 cd/m 2 en luminance maximale et possede un rendement quantique externe de 1%.

Recently, organic light emitting diodes have received a lot of attention in different research laboratories world-wide. Red, green and blue emitting devices are readily available. Devices with luminous efficiencies greater than 15 lm/W and lifetimes longer than 10,000 hours have been demonstrated. In this article, we will discuss the basic devices used in physics, materials used in organic light emitting diodes, device degradation mechanisms, and the opportunities of using this technology for commercial display applications.

Korea Basic Science Institute, Pusan Branch, Pusan National University, Pusan 609-735, KoreaReceived October 16, 2001Keywords : Electroluminescence, Pendant, Polyurethane, Organic electroluminescence device.There have been extensive research efforts on organicelectroluminescent devices (OELDs) with the aim of appli-cation for the flat panel display (FPD). OELDs have alsoattracted much interest because of their particular lowdriving voltage, convenient design of the device structures,possible control of emission band, and low fabrication costcompared with any other devices.

Bu tez çalışmasında, bir perilen diimid türevi olan N,N’-didodesilperilen- 3,4,9,10-bis-(dikarboksimide), (N-DODEPER) aromatik konjuge molekülü, yeşil ışık veren organik diyotta dopant olarak kullanılmış ve bu molekülün OLED performans etkisi araştırılmıştır. Boşluk taşıma katmanına yapılan doplama sonucu OLED cihazının EL verimi yaklaşık 6 cd/A olarak bulunmuştur. Döngüsel voltammetri ile N-DODEPER’in redoks potansiyelleri tespit edilmiştir. Tüm cihazların akım yoğunluğu, parlaklık ve elektrolüminesans (EL) değerleri akım-voltaj kaynağı, parlaklık ölçer ve fiber optik spektrometresiyle, normal cam üzerine kaplanan filmlerin absorpsiyon ve fotolüminesans (PL) özellikleri ise UV-Vis ve fluoresans spektrofotometresiyle elde edilmiştir.

The title complex, C44H32N2, is a useful charge-carrier transport material in organic electroluminescence devices. There are two half-molecules in the asymmetric unit; each molecule possesses a centre of symmetry at the mid-point of the central C—C bond.

Electrofluorescent organic light-emitting device with the structure of ITO/NPB/Alq3/LiF/Al and electrophosphorescent device with the structure of ITO/NPB/CBP: Ir（ppy）3/BCP/Alq3/LiF/Al were fabricated. Their electroluminescence properties were measured under an external magnetic field of 50 mT. Compared to the case of without magnetic field, the electroluminescent（EL） efficiencies of the above-mentioned two kinds of devices increase 44% and 7%, respectively. Based on the luminescence mechanism of organic light-emitting diodes （OLEDs）, the observed phenomena were explained. The origin of the improvement can be attributed to the Zeeman split of triplet state due to the external magnetic field influence, resulting in the conversion of triplets T+ into singlet S in the electrofluorescent device and an increase of the rate constants of triplet energy transfer from host to guest in electrophosphorescent device, respectively. At the same time, the reduced concentrations of triplet decreases the interaction of triplets with free carriers, resulting in an increase in the mobility of free carriers within the device and hence increasing the current.

As a fundamental study on organic electroluminescence(EL), blue emitting materials were synthesized and characterized. Individual blue colored hydrazone derivatives were synthesized from the reaction of aldehydes (phthalaldehyde, isophthalaldehyde) with the corresponding amnios (1-methyl -1-phenylhydrazine, 1,1-diphenylhydrazine hydrochloride). Recrystallization of hydrazones from chloroform revealed the melting temperature within . Photoluminescence(PL) analysis on each hydrazone showed that emission range were blue(458∼478 nm). The structure of obtained hydrazones were elucidated by FT-IR, H-NMR and C, H, N elemental analyzer.

We have prepared a device of C9-PPV sandwiched between two SiO2 layers and obtained the blue light in addition to the yellow-green emission under ac electric field excitation. By studying the optical characteristics of the device, we found that the emission was induced by direct bombardment of the accelerated electrons from SiO2. This emission is termed by us as cathodo luminescence-like emission. By using unsymmetrical structure, we realized mutual enhancement of cathodo luminescence-like and Organic electroluminescence.

Based on the Fowler-Nordheim tunneling injection, a model for carriers transport and recombination in organic bilayer devices at high electric field is presented. The influences of applied bias and interface barriers on carriers recombination and its efficiency are calculated and discussed. The theory derived from this model reasonably elucidates the experimental phenomena, and it proves that the electric field can control the carriers recombination region.

We have studied electroluminescence and impedance properties of exciplex-type organic light-emitting devices (OLEDs) based on 4,4,4″ - tris[3- methylphenyl (phenyl)-...