Preparation And Fluorescence Characteristics Of Organic Micro-Nano Thin Films By Hybrid And Stacking Methods

In this paper,based on the low-vacuum physical vapor deposition method,a simple organic small molecule micro-nano film was prepared.Through the preparation of theophylline/tetrafluoroterephthalic acid elemental organic micro-nano film,it was found that the theophylline fluorescence peak was increased from 1 to 4,which broadened the emission wavelength range by 100nm,2,3,5,6-tetrafluoroterephthalic acid.The relative fluorescence intensity between the fluorescence peaks of fluoroterephthalic acid changed.Compared with the raw material powder,the fluorescence peak at 408nm shifted blue by 7nm,and the fluorescence peak at 362nm shifted red by 3nm.In addition,with the gradual increase of the thickness of the elemental micro-nano film,its fluorescence efficiency also gradually increased.By characterizing the micronano film,it is found that as the thickness of the micro-nano film increases,the aggregate size of the particles gradually increases,thereby verifying the difference in photophysical properties between the film at the nanometer size and the same material at the macroscopic size In addition,we also found that in the elemental micro-nano film,the fluorescence intensity of the film will increase with the thickness of the film.Based on the similar melting point of TP and TFA,we also used the vacuum deposition method based on physical vapor,fully mixing the two material powders for vapor deposition.After the preparation of TFA mixed films with different thicknesses(stoichiometric ratio is 1:1),it was found that there is only a single peak at 362nm in the equal ratio mixed films,and the fluorescence peaks appear in other single film All disappear,and as the thickness of the film increases,the fluorescence intensity of the mixed film gradually increases.Surprisingly,the photos taken in the SEM electron microscope show that the aggregate morphology of the mixed film is completely different from that of the elemental film,showing a long rod-like structure.In addition,the aggregate size of the particles has reached the micron level.Therefore,we can assume that the two substances interacted in the process of mixed evaporation to form a new aggregation form and thus changed the fluorescence characteristics of the whole mixed film.By using different film preparation processes,TFA composite laminated micro-nano film was prepared by lamination method.In the experiment,the fluorescence characteristics of the laminated composite film were adjusted by adjusting the deposition sequence and the relative thickness of the two substances,so that another idea to adjust the photoluminescence characteristics of the crystal structure as the mainstream was proposed.