Study On Doping And Modification Of Tris(8-Hydroxy-Quinoline)Aluminum Micro-Crystals And Their Photo-Electronic Properties

Organic crystal materials have broad application prospects in organic semiconductor devices due to its advantages of long range order,less defects and good charge transfer performance.Doping is one of the most effective means to realize the contrable luminescence and improvement of charge transfer performance of organic crystals.Therefore,it is very important to synthesize organic doped crystals with good photoelectric properties.In this paper,the double-layer quenching method is adopted to successfully prepare mer-fac-Alq₃ self-doped microcrystalline materials according to the transformation of mer-Alq₃ into fac-Alq₃ at high temperature.The influences of amorphous film thickness,heating time and heating temperature on crystal morphology are studied.The best morphology of Alq₃ microcrystalline materials was obtained by heating 200 nm-thick amorphous film layer at 380?for 13 min.Then,the microstructure and chemical composition of the microcrystalline materials were characterized and analyzed by means of FTIR,XRD,UV-Vis and Raman.By regulating the heating time and temperature,the blue shift of luminescence peak of mer-fac-Alq₃ self-doped microcrystalline materials from 506 nm to 470 nm was achieved in this paper.The second harmornic generation properties of mer-fac-Alq₃ microcrystalline materials were characterized,and the relationship between nonlinear optical properties and doping structure was analyzed.Finally,single micro-rod devices were constructed by using shadow mask method,and the relationship between the improvement of electronic transmission performance of mer-fac-Alq₃ microcrystalline materials and the semiconductor characteristics of doped materials was analyzed.In order to further regulate the luminescence color and improve the electron transfer efficiency of microcrystalline materials,this paper improved the double-layer quenching method and successfully prepared Alq₃/Ir?ppy?₃ hetero-doped microcrystalline materials,and studied the influence of heating time and doping ratio on the crystal morphology.The microcrystalline morphology of Alq₃/Ir?ppy?₃ was the best after heating 200 nm-thick amorphous film at 380?for 11 min.Then,the composition and microstructure of microcrystalline materials doped with Ir?ppy?₃ in Alq₃?IDA?and Alq₃ doped in Ir?ppy?₃?ADI?were analyzed by means of FTIR,XPS and XRD.In this paper,the regulation of doping ratio on the luminescent color of Alq₃/Ir?ppy?₃ microcrystalline materials was discussed,and the luminescent color was changed from green to yellow to red to yellow.The wide range of excitation properties of Alq₃/Ir?ppy?₃ microcrystalline materials were characterized by fluorescence microscope and fluorescence spectrum.Under the excitation of 475 nm,ADI-and IDA-Alq₃/Ir?ppy?₃ microcrystalline materials emitted yellow and green light respectively.When excited at 532 nm or 632 nm,both materials emit red light.Through the fluorescence lifetime and transient absorption spectrum analysis of luminescence mechanism,Alq₃ has realized triplet state luminescence at room temperature for the first time.Finally,the micro-rod electrodes of Alq₃/Ir?ppy?₃microcrystalline material were constructed to analyze the relationship between the obvious improvement of its electron transfer efficiency and the doping of Ir?ppy?₃.