Study On Structure Activity Relationship And Application Of Low-power Upconversion Material

Low power upconversion based on triplet-triplet annihilation(triplet-triplet annihilation, TTA) has attracted much attention due to its potential applications in solar cells, photocatalysis, bioimaging, photoelectric device, three-dimensional optical storage, and so forth. In the field of domestic and foreign, the preparation, the relationship between structure and properties and the upconversion luminescence of the low power upconversion material is one of the key research.The main contents of this thesis include: 1. Design and Preparation of Materials: In this paper, to research the low power upconversion, we made some molecule designs about porphyrin and anthracene derivatives based the literature.a series of porphyrin and anthracene derivatives were synthesized. They are possess long phosphorescence lifetime: Pd(II) tetraphenylporphyrin(PdTPP), Pt(II) tetraphenylporphyrin(PtTPP) and with good fluorescence properties: anthracene(An), 9,10-diphenylanthracene(DPA), 2-chloro-9,10-di(naphthalen1yl)anthracene(DNACl),9,10-di(naphthalen1yl)anthracene-2-carbonitrile(DNACN),2-carbomethoxy-9,10-di(tolyl)anthracene(DTAMA), respectively. 2. Effect of metal complex to upconversion: In this research, the upconversion phenomenon of PdTPP / DTAMA and PtTPP / DTAMA was researched. On the other hand, We discussed the effect of metal palladium, platinum complex to the upconversion efficiency, found that palladium porphyrin favor the low-power upconversion。In DMF, as the triplet-triplet sensitizer PdTPP have longer phosphorescence life(15.4 μs), less non-phosphorescence decay rate constant(9.75×104 s-1)and lagerer phosphorescence quantum yield(0.45 %), these kinetic data have to the benefit of the enhancement the triplet-triplet energy transfer(TTT) efficiency. Ultimately, under low-powered excitation at 60 mW/cm2(532 nm), green-to-blue upconversion efficiency(Φuc) of DTAMA combined with PdTPP was as high as 19.12 % and the upconversion efficiency(Φuc) of PtTPP/DTAMA is 13.23 %, by the relative upconversion efficiency formula. So it proves that Palladium porphyrin derivatives are more conducive to improve the upconversion efficiency. We identified the palladium complex of porphyrin sensitizer are more suitable for the upconversion material, finally. 3. The structure of the emitter influence on upconversion: In this paper, we focus on the dynamics of acceptor fluorescence influencing the low power upconversion. It is found that the ratio of radiative(kf) and nonradiative(knr) decay rate constants dominates the acceptor fluorescence radiation approach. Experimental measurements associated with theoretical calculations revealed that the TTT efficiency(FTTT) and fluorescence quantum yield(Ff) play the key role on the upconversion efficiency(FUC) while the triplet-triplet annihilation(TTA) was found negligible. For the sake of low power upconversion application in photoelectrochemistry, We found the semiconductor photocatalyst ZnCdS is sensitive to blue light, and made this semiconductor as light anode. By green-to-blue upconversion fluorescence radiated the ZnCdS loaded on the FTO conductive glass, we have successfully observed the photocurrent response to upconverted blue light. 4. The research of performance about green-to-blue low power upconverted microemulsion: Made PdTPP as sensitizer, DPA and DNACl asemitters, prepared drug-free environmental, without oxygen degassing, air-stable upconverted microemulsion. We studied the phase transition about upconverted microemulsion, discovered the microemulsion phase transition temperature(PIT=38 OC), firstly. Eventually, we focus on the dynamics of sensitizer phosphorescence influencing the low power upconversion. It is found that the phosphorescence lifetime rather than the phosphorescence intensity of sensitizer is decisive to the upconversion efficiency. 5. The research on green-to-blue upconversion application: we first investigated the low-powered upconverted microemulsion driven the photodegradation of Rhodamine B(RhB). It was found that the green-to-blue upconversion is well fitted into the energy difference of valence and conduct bands of Zn CdS that can produce the decent charge separation by the upconversion irritation. As a result, the photodegradation efficiency of RhB is up to 80 % in the presence of ZnCdS, after 100 min green-to-blue upconversion irritation. To the best of our knowledge, the current study represents the first instance of low-powered upconversion-driven photodegradation. The significance in this study suggests that low-powered upconversion-driven photodegradation can be achieved for water purification and environmental remediation by the sun.