A novel binuclear europium P-diketone complex with squaric acid ligand was synthesized for the first time. Its structure was elucidated by IR, UV, and Elemental Analysis. Red light emitting diode (LED) was fabricated ...A novel binuclear europium P-diketone complex with squaric acid ligand was synthesized for the first time. Its structure was elucidated by IR, UV, and Elemental Analysis. Red light emitting diode (LED) was fabricated by using the novel europium complex as an emitting layer, tris(8-quinolinolate) aluminum (III) (Alq(3)) as an electron-transporting layer, N, N'-diphenyl-N, N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole-transporting layer. A cell structure of indium-tin-oxide/TPD/Eu-complex/Alq(3)/Mg: Ag was employed. Red electroluminescence was observed at room temperature with dc bias voltage of 2 V in this cell. 2 Red emission peaks at about 613 nm with maximum luminance of over 106 cd/m(2). Compared with the EL luminance from those europium complexes reported before, one from the Eu-complex is best in the same cells.展开更多
A series of Sc,Y,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Ho,Er,Tm and Yb complexes with oxybenzoquinoline ligands(BQ) was synthesized by the reactions of 10-hydroxybenzo[h]quinoline with cyclopentadienides or tris(trimethylsilyl)amides ...A series of Sc,Y,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Ho,Er,Tm and Yb complexes with oxybenzoquinoline ligands(BQ) was synthesized by the reactions of 10-hydroxybenzo[h]quinoline with cyclopentadienides or tris(trimethylsilyl)amides of rare earth metals.The structure,as well as the photo-and electroluminescent(PL,EL) properties of these complexes in solutions and solid state were studied.In solutions,complexes of sodium and lanthanides exhibit double peaked ligand-centered PL of enol and keto forms of BQ with a quantum yield of 1%-8%.In the solid state the complexes of Sm,Eu,Ho,Nd,Er,and Yb along with the ligand-centered PL also exhibit a moderate-intensity metal-centered PL which is characteristic of the corresponding Ln^(3+) ions.Sc(BQ)_(3) complex shows bright green EL which has intensity comparable to the best results observed for scandium complexes with other organic ligands.展开更多
Germanium （Ge） pin photodiodes show clear direct band gap emission at room temperature, as grown on bulk silicon in both photoluminescence （PL） and electro- luminescence （EL）. PL stems from the top contact layer...Germanium （Ge） pin photodiodes show clear direct band gap emission at room temperature, as grown on bulk silicon in both photoluminescence （PL） and electro- luminescence （EL）. PL stems from the top contact layer with highly doped Ge because of strong absorption of visible laser light excitation （532 nm）. EL stems from the recombination of injected carriers in the undoped intrinsic layer. The difference in peak positions for PL （0.73 eV） and EL （0.80 eV） is explained by band gap narrowing from high doping in n＋-top layer. A superlinear increase of EL with current density is explained by a rising ratio of direct/ indirect electron densities when quasi Fermi energy level rises into the conduction band. An analytical model for the direct/indirect electron density ratio is given using simplifying assumptions.展开更多
基金This work was supported by National Natural Science Foundation of China (29972032) and Provincial Natural Science Foundation of Hunan (00JJY2043).
文摘A novel binuclear europium P-diketone complex with squaric acid ligand was synthesized for the first time. Its structure was elucidated by IR, UV, and Elemental Analysis. Red light emitting diode (LED) was fabricated by using the novel europium complex as an emitting layer, tris(8-quinolinolate) aluminum (III) (Alq(3)) as an electron-transporting layer, N, N'-diphenyl-N, N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole-transporting layer. A cell structure of indium-tin-oxide/TPD/Eu-complex/Alq(3)/Mg: Ag was employed. Red electroluminescence was observed at room temperature with dc bias voltage of 2 V in this cell. 2 Red emission peaks at about 613 nm with maximum luminance of over 106 cd/m(2). Compared with the EL luminance from those europium complexes reported before, one from the Eu-complex is best in the same cells.
基金supported by the Russian Science Foundation (2073-10115)。
文摘A series of Sc,Y,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Ho,Er,Tm and Yb complexes with oxybenzoquinoline ligands(BQ) was synthesized by the reactions of 10-hydroxybenzo[h]quinoline with cyclopentadienides or tris(trimethylsilyl)amides of rare earth metals.The structure,as well as the photo-and electroluminescent(PL,EL) properties of these complexes in solutions and solid state were studied.In solutions,complexes of sodium and lanthanides exhibit double peaked ligand-centered PL of enol and keto forms of BQ with a quantum yield of 1%-8%.In the solid state the complexes of Sm,Eu,Ho,Nd,Er,and Yb along with the ligand-centered PL also exhibit a moderate-intensity metal-centered PL which is characteristic of the corresponding Ln^(3+) ions.Sc(BQ)_(3) complex shows bright green EL which has intensity comparable to the best results observed for scandium complexes with other organic ligands.
文摘Germanium （Ge） pin photodiodes show clear direct band gap emission at room temperature, as grown on bulk silicon in both photoluminescence （PL） and electro- luminescence （EL）. PL stems from the top contact layer with highly doped Ge because of strong absorption of visible laser light excitation （532 nm）. EL stems from the recombination of injected carriers in the undoped intrinsic layer. The difference in peak positions for PL （0.73 eV） and EL （0.80 eV） is explained by band gap narrowing from high doping in n＋-top layer. A superlinear increase of EL with current density is explained by a rising ratio of direct/ indirect electron densities when quasi Fermi energy level rises into the conduction band. An analytical model for the direct/indirect electron density ratio is given using simplifying assumptions.
