Home About us Contact
|
Home About us Contact | ||
|
|
||
Electroluminescence Devices (electroluminescence + device)
Selected AbstractsA Wide-Bandgap Semiconducting Polymer for Ultraviolet and Blue Light Emitting Diodes,MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 18 2003Ping Lu Abstract A novel wide-bandgap conjugated polymer (PDHFSCHD) consisting of alternating dihexylfluorene and rigidly twisted biphenyl units has been synthesized. The new fluorene-based copolymer composed of rigid twisting segments in the main-chain exhibits an optical bandgap of as high as 3.26 eV, and a highly efficient ultraviolet emission with peaks at 368 nm and 386 nm. An electroluminescence device from PDHFSCHD neat film as an active layer shows UV emission which peaks at 395 nm with a turn on voltage below 8 V. By optimizing the device conditions, a peak EL quantum efficiency of 0.054% and brightness of 10 cd,·,m,2 was obtained. Furthermore, blending a poly(dihexylfluorene) in the PDHFSCHD host gave pure blue emission peaking at 417 nm and 440 nm without long wavelength emission from aggregated species. Efficient energy transfer from PDHFSCHD to PDHF was demonstrated in these blended systems. Depressed chain-aggregation of PDHF in the PDHFSCHD host can correspond to pure blue emission behaviors. The structure of the copolymer PDHFSCHD. [source] Low-Driving-Voltage Electroluminescence in Perovskite FilmsADVANCED MATERIALS, Issue 36 2009Hiroshi Takashima Perovskite thin-film electroluminescence devices are prepared, opening up a new optical application of perovskite materials. With increasing driving voltage, the intensity of electroluminescence increases dramatically. High-quality red color is produced and the working voltage for whole-surface electroluminescence is as low as 10 V. [source] Synthesis of silicon-bridged polythiophene derivatives and their applications to EL device materialsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2007Joji Ohshita Abstract Palladium-catalyzed oxidative homo-coupling of 2,6-bis(tributylstannyl)dithienosiloles with CuCl2 afforded poly(dithienosilole-2,6-diyl)s as novel polythiophene derivatives with intra-chain silicon bridges, which exhibited red-shifted UV absorption maxima by about 100 nm from those of the corresponding silole-free polythiophenes. Alternate copolymers also were prepared by palladium-catalyzed cross-coupling reactions of 2,6-dibromodithienosiloles with distannylthiophene or bithophene. These polymer films were applied to single and double-layered organic electroluminescence devices. It was found that some of the resulting polymers exhibited electroluminescence properties and emitted red light in EL devices with the structure of ITO/polymer/Mg-Ag. Introducing an electron-transporting Alq3 layer between the polymer film and the Mg-Ag cathode led to a remarkable improvement in the devices performance. An application of the copolymer to a field effect transistor was also studied. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4588,4596, 2007 [source] Versatile preparation of poly(1,4-phenylenevinylene- co -1,4-phenylene-1,2-ethanediyl) by CVD polymerization of p -(methoxymethyl)benzyl chlorideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2005Ngo Trinh Tung Abstract It was demonstrated that a series of copolymers consisting of 1,4-phenylenevinylene (PV) and 1,4-phenylene-1,2-ethanediyl (PE) units could be prepared from a single monomer, p -(methoxymethyl)benzyl chloride, via the chemical vapor deposition polymerization (CVDP) method. The composition of the copolymers could be varied simply by altering the monomer activation temperature. The higher the temperature, the lower the content of the PV unit. The photo (PL)- and electroluminescence (EL) properties of the copolymers that revealed a blueshift when compared with PPV strongly depend on the amount of the PE units incorporated. The external quantum efficiencies of the electroluminescence devices having the configuration of ITO/PEDOT-PSS/copolymer/Al-Li were higher than that of PPV, which can be ascribed to the improved confinement of excitons. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 742,751, 2005 [source] | ||||||||||