A novel terbium (III) beta-diketonate complex as thin film for optical device application

A novel terbium complex, Tb(acac)(3)AAP (acac: acetylacetone, AAP: 4-amino-antipyrine), was synthesized and its luminescent properties were studied. When it was used as an emitting center, triple-layer-type device with a structure of glass substrate/ITO (indium-tin oxide)/TPD (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine)./Tb(acac)(3)AAP/PBD (2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole) or Alq(3) (tris(8-hydroxyquinolinato) aluminum)/Al (aluminum) exhibited bright characteristic emission of terbium ion upon applying d.c. voltage. The maximum luminance of the device is 56 cd/m(2) at 19 V and the maximum luminance efficiency is 0.357 lm/W.

Synthesis of novel nitrogen- and sulfur-containing conjugated polymers used as hole-transporting materials for organic light-emitting diodes

Two series of highly soluble novel nitrogen- and sulfur-containing conjugated polymers were synthesized via an acid-induced self-polycondensation of functional monomers with methyl sulfinyl and aromatic groups. The well-defined structures of synthesized polymers were confirmed by their NMR and IR spectra. The highest occupied molecular orbital energy values for these materials, estimated by cyclic voltammetry, showed a broad range of values from about 5.0 to 5.2 eV used as hole-transport layers (HTL) in two-layer light-emitting diodes ITO/HTL/Alq(3)/Mg:Ag [ITO = indium tin oxide, and Alq(3) = tris(8-quinolinato) aluminum]. The typical turn-on voltage of these diodes was about 4-5 V. The maximum brightness of the device was about 3440 cd/m(2) at 20 V. The maximum efficiency was estimated to be 0.15 1m/W at 10 V.

A novel way to enhance electroluminescence performance based on soluble binary and ternary europium 1,1,1-trifluoroacetylacetonate

Five rare earth complexes (Gd(acae)(3), Gd(TFacaC)(3), Eu(acaC)(3), Eu(TFacaC)(3) and Eu(TFacaC)(3)bipy; acac, acetylacetone; TFacac, 1,1,1-trifluoroacetylacetone; bipy, 2,2'-bipyridyl) were synthesized. By comparing the phosphorescence spectra of Gd(acac)(3) and Gd(TFacac)(3) the effect of the replacement of hydrogen by fluorine was examined. Organic light-emitting devices (OLEDs) based on the corresponding europium complexes as emissive layers were also fabricated by the spin-coating method. The triple-layer-type device with the structure glass substrate/ITO (indium-tin oxide)/PVK [poly(N-vinylcarbazole)]/(PVKEu)-Eu-.(TFacac)(3)bipy:PBD[2-(4-bibipyyl)-5-(4-t-butylbipyl-1,3,4-oxadiazole)]/PBD/Al (aluminum) exhibits a brighter red luminescence than those devices with Eu(acac)(3) and Eu(TFacac)(3) complexes as emissive centers upon applying a d.c. voltage.

Red electroluminescent device with europium 1,1,1-trifluoroacetylacetonate complex as emissive center

By comparing the phosphorescence spectra of Gd(acac)(3) (acac: acetylacetone) and Gd(TFacac)(3) (TFacac: 1, 1, 1-trifluoro-acetylacetone), the effect of fluorine replacing of hydrogen was discussed. It can lower the triplet state energy of acac and make it more suitable to the D-5(1) energy state of europium. Organic electroluminescent (OEL) devices with corresponding europium complexes as emissive layers were fabricated. A triple laver-type device with a structure of glass substrate/indium-tin oxide (ITO)/poly(N-vinylcarbazole) (PVK)/PVK:Eu(TFacac)(3)phen:2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD)/PBD/Al exhibits bright red luminescence upon applying dc voltage, The device has the properties of a diode and the current-bias voltage line was obtained.

1.54 mu m infrared photoluminescence and electroluminescence from an erbium organic compound

Infrared emission at 1.54 mu m excited optically and electrically from an erbium organic compound tris(acetylacetonato)(1,10-phenanthroline) erbium [Er(acac)(3)(phen)] is observed. The rare-earth complex is dispersed into a polymer matrix of poly(N-vinylcarbazole) (PVK) to fabricate an electroluminescent (EL) device with an ITO/PVK:Er(acac)(3)(phen)/Al:Li/Ag structure, where ITO represents indium-tin-oxide-coated glass. The device shows infrared EL emission at 1.54 mu m, which suggests a simple and cheap method to obtain a light source for 1.54-mu m-wavelength devices in optical communications. (C) 2000 American Institute of Physics. [S0021-8979(00)00301-7].

A comparative study on the electroluminescence properties of some terbium beta-diketonate complexes

By comparing the phosphorescence spectra of Gd(acac)(3) (acac=acetylacetone), Gd(TFacac)3 (TFacac=1,1,1-trifluoroacetylacetone), the effects of fluorine replacement of hydrogen on the triplet state energy of the ligands were revealed. Fluorine can lower the triplet state energy of Hacac and make it more suitable for energy transfer towards the D-5(4) state of terbium. Organic electroluminescent devices (OELDs) with the corresponding trivalent terbium complexes as emissive layers were fabricated. Triple-layer-type devices with a structure of glass substrate/ITO (indium tin oxide)/PVK [poly(N-vinylcarbazole)]/PVK : Tb complex: PBD [2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole]/PBD/Al exhibit bright green luminescence upon applying a dc voltage. The luminance of a device with Tb(TFacac)(3)phen (1,10-phenanthroline) and Tb( TFacac) 3 as emissive layer is higher than that of the corresponding devices with Tb(acac)(3)(phen) and Tb(acac)(3) as emissive layers. The EL device with Tb(TFacac)(3)(phen) as emitter exhibits characteristic emission of Tb3+ ions with a maximum luminance of 58 cd m(-2) at 25 V.

Bright green organic electroluminescent devices based on a novel thermally stable terbium complex

A navel thermally stable terbium carboxylate complex, Tb(MTP)(3)(phen) (MTP=monotetradecyl phthalate, phen=1,10-phehanthroline), was synthesized and characterized. The device structure of glass substrate/indium-tin-oxide/poly(p-phenylenevinylene) (PPV)/poly (N-vinycarbazole) (PVK):Tb(MTP)(3)(phen): 1,3,4-oxadizole derivative (PBD)/tris(8-hydroxyquinoline) (Alq(3))/aluminum (Al) was employed to study the electroluminescent properties of Tb(MTP)(3)(phen). A green emission with extremely sharp spectral band of less than 10 nm at 544 nm peak wavelength was observed. A maximum luminance of 152 cd/m(2) and an external quantum efficiency of 0.017% were achieved at a drive voltage of 24 V. A possible mechanism of energy transfer based on the polymer doped with lanthanide organic complex was also proposed.

Bright red organic electroluminescent devices based on a soluble rare earth complex Eu(TTA)(3) Phen

An Electroluminescent device with PVK film doped with Eu(TTA)(3) Phen and PBD was fabricated. The device structure of glass substrate/indium-tin-oxide/PPV/PVK : Eu(TTA)3 Phen : PBD/Alq(3)/Al was employed. A sharply red electroluminescence with a maximum luminance of 56. 8 cd/m(2) at 48 V was achieved.

Bright red electroluminescent devices based on a soluble lanthanide complex Eu(DBM)(3)(phen)

Electroluminescent devices with PVK film doped with Eu(DBM)(3)(phen) and PBD were fabricated. The device structure of glass substrate/indium-tin-oxide/PPV/PVK:Eu(DBM)(3)-(phen):PBD/Alq(3)/Al was employed. The emissive layer was formed by spin-casting method. A sharply red electroluminescence with a maximum luminance of 114.4 cd/m(2) was achieved at 42 V.

Bright blue electroluminescent devices utilizing poly (N-vinylcarbazole) doped with fluorescent dye

Bright blue electroluminescent devices have been fabricated using poly (N-vinylcarbazole) (PVK) doped with perylene as the emissive layer, poly(p-phenylenevinylene) (PPV) as the hole-transporting layer, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), tris(8-hydroxyquinoline)aluminum (Alq(3)) as the electron-transporting layer, and Al as the cathode. A luminance of 700 cd/m(2) and a luminescent efficiency of 0.8% are achieved at a drive voltage of 36 V. In the experiment, it is found that the introduction of electron-transporting layer PBD has a great effect on the emissive color of the electroluminescent devices prepared by PVK doped with perylene. Yellow-green emission is observed from the device structure of glass substrate/indium-tin-oxide/PVK:perylene/Al. The possible emissive mechanisms are given. The effect of the transporting layer on the electroluminescence is also discussed. (C) 1997 Elsevier Science S.A.

Electropolymeric generation of optically active polypyrrole

The facile synthesis of optically active polypyrrole has been achieved via the enantioselective electropolymerization of pyrrole on indium-tin-oxide-coated glass electrodes in aqueous solution containing D-(+) or L-(-) tartaric acid, (1S)-(+)-10-camphorsulfonic acid and L-lactic acid. The dark films of conducting polypyrroles salt formed under electrostatic conditions (+0.65V vs. Ag/AgCl) exhibited strong circular dichroism (CD) spectra typical of polymers possessing helical chirality. The quantitative reversal of the CD spectrum of the salt grown in (+)-tartaric acid as opposed to (-)-tartaric acid suggests that electropolymerization is highly enantioselective, with one helical screw of the polymer chain being preferentially produced depending on the hand of the tartaric anion incorporated. (C) 1997 Elsevier Science Ltd.

The fabrication of dipped CdS and sputtered ITO thin films for photovoltaic solar cells

Stable bilayer thin films of indium tin oxide (ITO) on CdS and CdS on ITO were formed for the window material of solar cells by chemical bath and sputtering methods. Scanning electron microscopy and X-ray diffraction studies have shown that both the ITO and CdS films are continuous, homogeneous, with high compactness. Measurement of the CdS film thickness across the 2 x 4 cm(2) reveals the good uniformity of these films. Four-point probe measurements show that the resistivity of a CdS film on an ITO surface is much better than that of the single CdS film The thermal stability of an ITO/CdS bilayer, interfacial reaction and optical transmittance were investigated at different annealing temperatures and environments (air, vacuum and N-2 + H-2). The results showed that the ITO/CdS bilayer film is a good window material for the CuInSe2 and CdTe cells. It is a simple method using a small amount of the cadmium compound.

Continuous non-destructive monitoring of cell health using impedance based interdigitated electrode structured sensors

This article examines some preliminary tests which were performed in order to evaluate the best electrode configuration (width and spacing) for cell culture analyses. Biochips packaged with indium tin oxide (ITO) interdigitated electrodes (IDEs) were used to perform impedance measurements on A549 cells cultured on the surface of the biochip. Several tests were carried out using a 10 mM solution of Sodium Chloride (NaCl), cell medium and the cell culture itself to characterize some of the configurations already fabricated in the facilities at Tyndall National Institute.

A highly efficient sensor platform using simply manufactured nanodot patterned substrates

Block copolymer (BCP) self-assembly is a low-cost means to nanopattern surfaces. Here, we use these nanopatterns to directly print arrays of nanodots onto a conducting substrate (Indium Tin Oxide (ITO) coated glass) for application as an electrochemical sensor for ethanol (EtOH) and hydrogen peroxide (H

Synthesis of a neodymium-quinolate complex for near-infrared electroluminescence applications

A structurally pure, near-infrared emissive Nd-(5,7-dichloro-8-hydroxyquinoline)4 tetrakis complex has been synthesized. When incorporated as a dopant in the blue emissive, hole conducting polymer poly(N-vinylcarbazole), PVK, sensitized neodymium ion emission was observed following photo-excitation of the polymer host. OLED devices were fabricated by spin-casting layers of the doped polymer onto glass/indium tin oxide (ITO)/3,4-polyethylene-dioxythiophene-polystyrene sulfonate (PEDOT) substrates. An external quantum efficiency of 1 x 10(-3)% and a near-infrared irradiance of 2.0 nW/mm(2) at 25 mA/mm(2) and 20 V was achieved using glass/ITO/PEDOT/ PVK:Nd-(5,7-dichloro-8-hydroxyquinoline)(4)/Ca/Al devices. (C) 2007 Elsevier B.V. All rights reserved.