Insulator Effects Of Organic Field Effect Transistors Based On Lanthanide Compound And Magnetic Properties Of PolynuclearCompounds Based On 3-Methoxy-salicylaldehyde-azine

Organic field-effect transistors (OFETs) have attracted much attention owing to their various potential applications, such as flexible displays, sensors, radio-frequency identification tags, etc. Great progresses have been made, i.e., the performance of OFETs comparable to that of amorphous silicon field effect transistors. From the viewpoint of practical applications, OFETs still face the challenges, including the device performance needed to be further improved, the explanation of intrinsic correlation between the thin-film microstructure and the corresponding device performance, and the operating voltages needed to be reduced to several volts.We have successfully fabricated low-voltage pentacene-based FETs by using complex OTS/PVA/Eu(tta)3’L as gate dielectric. The insulating layer has root mean square (RMS) roughness value of 0.476 nm. Low leakage current densities (-5-+5 V, 10-9-10-7 A cm-2) and relatively high capacitance density (33 nF cm-2) and relative dielectric constant (11). The field-effect mobility (μ) is 0.17 cm2V-1s-1 at -5 V, comparable to SiO2 insulator (0.13 cm2V-1s-1 at -30 V); on/off ratio is 5×103; threshold voltage (Vt), and subthreshold swing (S) are -0.9 V and 1.0 V dec-1, which are obviously superior to those of SiO2/Si substrates (-7.3 V and 3.1 V dec-1). It is of significance to develop low-voltage OFETs based on high-κ lanthanide complexes as gate insulator.In recent years, molecule-based magnetic materials have been an important focal research field in chemistry, physics and material science because of their potential applications in such as high density magnetic storage, quantum computation and spintronic devices. This research field contains:single molecule magnets, chiral magnets, molecule-based photomagnets, ferromagnetic molecular conductors, magnetic superconductors and so on. The use of molecules or molecular assemblies for information processing is one of the most appealing perspectives in molecular chemistry.We also desighed two compounds based on 3-Methoxy-salicylaldehyde-azine (H2msda), [Ni3(msda)2](DMF)2·H2O·ClO4 (1) and [Co2(msda)3]·(DMF)2·H2O (2) which were prepared by hydrothermal synthesis and characterized by elemental analysis, IR, and X-ray single-crystal diffraction. Compounds 1 and 2 exhibited the different structures although the synthesis method is same. Compound 1 shows the strictly linear tri-nuclear structure in which three nickel(Ⅱ) centers bridged by oxygen atoms of water, while compound 2 is a dinuclear with two cobalt(Ⅲ) centers bridged by nitrogen atoms of azine groups. Magnetic properties of 1 in the 300-2 K have been discussed, which reveal the occurrence of anti-ferromagnetic coupling between nickel(Ⅱ) ions from the nature of the binding modes through μ2-water groups. Furthermore, the luminescent properties of compounds 1 and 2 were investigated.