Preparation And Application Research Of Blue Upconversion Luminescence Materials

Recent years,in the field of upconversion research such as the traditional rare earth upconversion and two-photon absorption upconversion,the upconversion based on triplet-triplet annihilation mechanism（TTA-UC）is one of the hot spot.Compared with the traditional upconversion technology,the excitation energy of TTA-UC is much lower and the UC emission range can be changed easily through modifying the structures of the sensitizer and emitter and the upconversion efficiency is relatively higher.So far,the researchers have more efforts to study the sensitizers,numerous researches of all kinds of sensitizers have been reported,but the study of emitters is much fewer.In this paper,three series of light-emitting materials have been designed and synthesized,and two of the series compounds were used as emitters in the TTA-UC.The green-to-blue upconversion fluorescence with the efficiency as high as 21.7% was successfully observed under 532 nm green light excitation（70 mW/cm-2）.The main contents in this study include:1.Five new phenanthrene derivatives were synthesized,and the structures were also characterizied.These phenanthrene derivatives were found to possess aggregation-induced emission enhancement（AIEE）with H-type aggregation,based on the absorption spectra measurements.2.Four kinds of new heterocyclic substituted anthracene derivatives were synthesized and characterizied by 1HNMR and LC-MS measurements.Two compounds were selected as emitters of TTA-UC systems.The upconversion fluorescence emission was observed.The highest upconversion efficiency of those TTA-UC systems was up to 10.1%.3.Also,two new dendritic anthracene derivatives were synthesized and characterizied by 1HNMR and LC-MS measurements.After the test of their fluorescence emission spectrums,the fluorescent quantum yield of this two compounds were high.Blue upconversion fluorescence based on triplet-triplet annihilation was observed when this two compounds as emitters homemade under the 532 nm green laser excitation,and the highest upconversion efficiency reached 21.7%4.Pt/WO₃ photocatalyst was prepared in this paper.We successfully converted coumarin to 7-hydroxycoumarin under the upconversion fluorescence with the existence of Pt/WO₃.In addition,this paper we also prepared three kinds of palladium porphyrin sensitizers.