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Electroluminescent Polymers (electroluminescent + polymer)

Distribution by Scientific Domains

Polymers and Materials Science	100%

Selected Abstracts

Electrophosphorescent Polyfluorenes Containing Osmium Complexes in the Conjugated Backbone,

ADVANCED FUNCTIONAL MATERIALS, Issue 9 2008
Chen-Han Chien
Abstract Electrophosphorescent copolymers have been synthesized by covalent bonding of a red-emitting osmium complex Os(bpftz), which contains two 3-trifluoromethyl-5-(4- tert -butyl-2-pyridyl)triazolate (bpftz) cyclometalated ligands, into the backbone of a bipolar polyfluorene (PF) copolymer. Employing these copolymers, a highly efficient red polymer light-emitting diode has been realised that has an external quantum efficiency of 18.0%, a maximum brightness of 38,000,cd,m,2, and an emission centered at 618,nm. In addition, after incorporating appropriate amounts of green-emitting benzothiadiazole (BT) and the aforementioned Os(bpftz) into the bipolar PF, an efficient white-light electroluminescent polymer is obtained that displays simultaneous blue, green, and red emissions. [source]

Design of Hole Blocking Layer with Electron Transport Channels for High Performance Polymer Light-Emitting Diodes,

ADVANCED MATERIALS, Issue 10 2008
Chung-Chin Hsiao
A novel dual-functional composite layer composed of a high ionization potential nonconjugated polymer or conjugated molecular material and an inorganic salt of a low work function metal is demonstrated. The composite provides superior hole blocking along with promising electron transport capability and results in good device performance for two model electroluminescent polymers, PFO and MEH-PPV. [source]

Phenylene vinylene-based electroluminescent polymers with electron transport block in the main chain

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2006
Honghao Sun
Abstract We report a new route for the design of soluble phenylene vinylene (PV) based electroluminescent polymers bearing electron-deficient oxadizole (OXD) and triazole (TZ) moieties in the main chains with the aryloxy linkage. Both series of the PV-based polymers were prepared by Wittig reaction. By properly adjusting the OXD and/or TZ content through copolymerization, we can achieve an enhanced balance of hole- and electron injections, such that the device efficiency is significantly improved. Light-emitting diodes fabricated from P1, P2, P3, P4, P5, P6, and P7 with the configuration of Indium,Tin Oxide (ITO)/Poly (styrene sulfonic acid) doped poly (ethylenedioxythiophene) (PEDOT)/polymer/Ca/Al, emit bright green light with the maximum peak around 500 nm. For the device using the optimal polymer (P4) as emitting layer, a maximum brightness of 1300 cd/m2 at 20 V and a maximum luminance efficiency of 0.325 cd/A can be obtained. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3469,3478, 2006 [source]

Improved EL efficiency of fluorene-thieno[3,2- b]thiophene-based conjugated copolymers with hole-transporting or electron-transporting units in the main chain

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2006
Eunhee Lim
Abstract New electroluminescent polymers (poly(9,9,-dioctylfluorene- co -thieno[3,2- b]thiophene- co -benzo[2,3,5]thiadiazole) (P1) and poly(9,9,-dioctylfluorene- co -thieno[3,2- b]thiophene- co -benzo[2,3,5]thiadiazole- co -[4-(2-ethylhexyloxyl)phenyl]diphenylamine (P2)) possess hole-transporting or electron-transporting units or both in the main chains. Electron-deficient benzothiadiazole and electron-rich triphenylamine moieties were incorporated into the polymer backbone to improve the electron-transporting and hole-transporting characteristics, respectively. P1 and P2 show greater solubility than poly(9,9,-dioctylfluorene- co -thieno[3,2- b]thiophene (PFTT), without sacrificing their good thermal stability. Moreover, owing to the incorporation of the electron-deficient benzothiadiazole unit, P1 and P2 exhibit remarkably lower LUMO levels than PFTT, and thus, it should facilitate the electron injection into the polymer layer from the cathode electrode. Consequently, because of the balance of charge mobility, LED devices based on P1 and P2 exhibit greater brightness and efficiency (up to 3000 cd/m2 and 1.35 cd/A) than devices that use the pristine PFTT. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 243,253, 2006 [source]