The Characteristics Of Rare Earth Sm-Doped Bis(8-hydroxyquinoline) Copper Films

Organic semiconductors have been allured much more attentions, because of their novel optoelectronic performances, mechanical flexibility, convenience for preparation, chemical modifying, good plasticity and so on. Organic semiconductors are mainly composed of light elements such as C, H, O, and N, with weak spin-orbit coupling and long time spin relaxation. Furthermore, the organic semiconductors also have unusual application potential in the field of spintronics. Especially, the 8-hydroxyquinoline metal complexes, which have simple structures, convenience for synthesis, excellent optoelectronic performances and thermal stability, have great potential applications such as in the organic light-emitting diodes(OLED), organic nanometer device, organic spin valve.The bis(8-hydroxyquinoline) copper (Cuq2) have simple molecular structure and versatile properties. On the other hand, the Cuq2 show visual phase transformations in macro. With the spontaneous spin polarization, the Cuq2 is one of researching hotspots for organic materials nowadays. To the best of our knowledge, they have great potential application in the field of organic magnets and organic spintronics.In this paper, there are two points in the process of our research. One hand, the Cuq2 films were deposited by thermal evaporator. In addition, we observed that the Cuq2 amorphous films can transform into organic crystalline structures under different annealing temperatures. The optical properties of the films were investigated. On the other hand, the structure and magnetism of Cuq2, which is doped by rare earth elements, were evaluated.In this thesis, the main contents and conclusions are as follows:(1) We have firstly found that the Cuq2 films, which were prepared by thermal evaporation and doped by Sm and Dy, respectively, have intrinsic ferromagnetic properties at room temperature. We could observe the enhanced saturated magnetization and coercive force as the Sm and Dy concentration in Cuq2 decreased, respectively. It is obvious that there were the disappearance of old peaks and emergence of new peaks, by comparing the pure Cuq2 FTIR with Sm-doped Cuq2. In summary, the Sm atoms have bonded with Cuq2 molecules.(2) It was found that there were some micro/nano Cuq2 grains, which were large and had good regularity, in the Cuq2 films after annealing. The crystallization of the Cuq2 became better after annealing. The sizes of the grains became larger as the annealing temperature rising gradually. The annealing temperatures are 80℃,100℃, 120℃and 150℃, respectively. The annealing time is two hours and the rate of high purity Ar gas is 0.3 L/min. At the same time, the nominal mole ratio of Sm and Cuq2 is about 1:1.(3) We have observed that the pure Cuq2 have weak luminescence performances at room temperature by investigating the photoluminescence spectra. But its luminescence performances are better at low temperature, especially at 220 K. The main PL peak blueshifted at low temperature. We noted that simultaneous PL emissions of R, G and B have been observed from annealing Cuq2. We found that the luminescence performances of the film were affected easily by Cu ions. Therefore, the photoluminescence become weaker. When the film is doped by Sm ions, the photoluminescence become better.