Summary: Homopolymers and a series of copolymers with tris‐8‐hydroxyquinoline aluminum (Alq3) as the cross‐links are synthesized. All these polymers show improved electroluminescence (EL) efficiency over their previously reported counterparts. Among them, the copolymers containing Alq3 and carbazole groups show higher EL efficiency than that of the homopolymers. We also demonstrate the feasibility of generating patterns using the homopolymers via photopolymerization. The cross‐linked nature, selectivity of patterning, high thermal stability, and EL efficiency might render these polymers a promising material in fabricating large‐scaled multilayered sub‐pixellation organic light‐emitting diodes (OLEDs).
Current–voltage and the electroluminescence–voltage curve of two‐layer devices for the Alq3‐homopolymers and the Alq3‐copolymers (luminance is shown by the symbols without lines). 相似文献
Aluminum and zinc complexes of 4‐substituted 8‐hydroxyquinoline were used effectively as emissive materials in light‐emitting diodes (LED). The substituents chosen in this study were p‐methoxy‐2‐styryl, p‐diethylamino‐2‐styryl, and naphthalene‐2‐vinyl groups. Their emission spectra were red‐shifted with respect to that of aluminum tris(hydroxylquinolate) (Alq3) as a result of extending their π‐conjugation. All complexes formed amorphous glasses, which exhibited high thermal and electrical stability. Typical LED devices were fabricated by mixing the dyes with polyvinylcarbazole and spin‐coated to form thin films, which were sandwiched between ITO (indium tin oxide) and a metal electrode. These devices displayed yellow‐orange emissions with quantum efficiency ca. 0.4%. 相似文献
Degradation phenomenon and poor stability of tris(8-hydroxyquinoline) aluminum(III)(Alq3)-based organic light-emitting diodes(OLEDs) have attracted much attention. In this paper, we discussed the origin of instability of the facial Alq3-based blue luminescent OLEDs with the help of first-principles calculation. The results show that environmental humidity seriously affects the luminescence stability of Alq3-based OLEDs. H2O molecules in environment can be firmly bound to the oxygen atoms of the facial Alq3, which then act as starting points for further degradation of Alq3. Moreover, the interactions between facial Alq3 and different cathode metal layers were investigated to explain the experiment phenomenon. A design guideline for diminishing the strong attraction from oxygen atoms can be proposed to protect Alq3 and improve the stability of materials applied in OLEDs. 相似文献
M3NS3, the First Nitride Sulfides of the Lanthanides (M = La? Nd, Sm) . The oxidation of the “light” lanthanides (M = La? Nd, Sm) with equimolar amounts of sulfur in the presence of NaN3 as nitrogen source results in the formation of the first lanthanide nitride sulfides: M3NS3 (evacuated silica vessels, some NaCl as flux, 850°C, 7 d). NaCl is afterwards removed from the not moisture sensitive crude product (faint- or orange-yellow to amber-co- loured transparent needles, oftenly intergrown to feltlike bunches) upon rinsing with water. The crystal structure was determined from X-ray single crystal data for the example of Sm3NS3 (orthorhombic, Pnma (no. 62), a = 1 201.18(7), b = 394.32(3), c = 1 285.27(6) pm, Z = 4, R = 0.027, Rw = 0.024), and M3NS3 (M = La? Nd) proved to be isostructural from Guinier powder data. There are three crystallographically different M3+ cations in six- (1 X) and sevenfold (2 X) coordination of the N3? and S2? anions. [(N3?)(M3+)4] tetrahedra connected via two corners forming linear chains [N(M1)1/1(M2)1/1(M3)2/2] 6+ build up the main structural feature. Arranged in the manner of a closest packing of rods, they are held together by three crystallographically different S2? which take care for charge neutrality and three-dimensional interconnection. 相似文献
