Based On The Asymmetry Of Zn (ii)-ln (iii) Schiff Base Complexes Of Light Caused By Near-infrared Light-emitting And Light-emitting Devices Of Study

Near-infrared (NIR) luminescence of 4f rare earth ions has increasingly attracted great interest over the last few years, because of the potential significant technical applications in sensor, laser system, optical telecommunications and fluorescent imaging. Till now, a variety of antenna groups have been designed to sensitize the NIR luminescence from Nd(III), Er(III), Yb(III) ions, overcoming very low extinction coefficients resulting from parity-forbidden f-f transitions of lanthanide ions.In this thesis, the NIR luminescence from the lanthanide(III) ions is sensitized from asymmetric Schiff base zinc compounds. Twenty four new compounds were synthesized, and their luminescent properties were also studied in detail. By selecting an obtained complex with preferable optical property as the host material, a NIR OLED was fabricated and its near-infrared electroluminescence was checked.Firstly, the asymmetric schiff-base ligand (H2L1) was obtained from the reaction of methyl-ethylenediamine and o-vanillin in good yield. With the [ZnL1Py] as the precursor, the series of Zn-Ln bimetallic compounds [Zn(L1)Ln(NO3)3Py] (Ln= Nd, 2; Ln=Yb,3; Ln= Er,4; Ln= Gd,5) were assembled. Their molecular structures were characterized and the intra-molecular energy transfer was also studied. Furthermore, another series of Zn-Ln bimetallic compounds [Zn(L2)Ln(NO3)3Py] (Ln= Nd,7; Ln=Yb,8; Ln=Er,9; Ln= Gd,10) based on the replacement of H2L2 with the heavy-atom (Br) effect. Their molecular structures and photophysical properties were also discussed.Secondly, two new asymmetric schiff-base ligands of H2L3 and H2L4 were obtained by the condensation reaction of 3-benzoyl-o-phenylenediamine with o-vanillin or 5-bromo-3-methoxy-benzaldehyde. Two series of bimetallic Zn-Ln compounds (complexes 12-15 and complexes 17-20) were obtained. Their structures were characterized by EA, FT-IR, UV-Visble absorption spectra, and the photophysical properties were discussed.Two series of cyclic tetranuclear Zn2-Ln2 compounds (complexes 12-15 and complexes 17-20) were obtained. Their structures were characterized by EA, FT-IR, UV-Visble absorption spectra, and the photophysical properties were discussed.Thirdly, two asymmetrical Schiff base ligands H2L5 and H2L6 were designed and in situ synthesized on the basis of above idea with the use of using 2,3-diaminophenol to obtain the two precursors [ZnHL5Py] (21) and [ZnHL6Py] (22). From the further self-assembly, two series of cyclic tetranuclear Zn2-Ln2 compounds [Zn2(L5)Ln2(NO3)4(Py)2(DMF)2] (Ln= Nd,23; Ln=Yb,24; Ln= Er,25; Ln= Gd, 26) and [Zn2(L6)Ln2(NO3)4(DMF)4] (Ln= Nd,27; Ln=Yb,28; Ln= Er,29; Ln= Gd, 30) were obtained.Their luminescent properties were examined, and the affect of heavy atom (Br) and the axial occupation of Py groups on the 3d Zn(II) ions was also analysized.Finally, a NIR OLED device was fabricated by doping the selected complex 8 and CuPc as the host material of the emitting layer. The structure of device was ITO/TPD(40 nm)/CuPc(x%, x= 0,5,10,15):8 (30 nm)/TPBI/LiF:Al (1:150 nm). The solid NIR EL spectra showed that theλem lies at 980 nm, similar to that of solution, which validates the potential applications on NIR OLED.