环糊精增强金属卟啉/蒽衍生物上转换及其应用

Study on the Cyclodextrin Enhanced Upconversion Based on Metalloporphyrins/Anthracene Derivatives

摘要:

摘要：弱光上转换是借助于三线态-三线态湮灭机制，通过吸收低能量（长波长）的光，尔后发射高能量（短波长）光的一种技术，通常是由发光剂与光敏剂复配构成二元体系来实现的。本文通过不同空腔半径的环糊精（-、-和-CD）包络发光剂（2-氯-9,10-二甲苯基蒽，DTACl），分别与光敏剂5,10,15,20-四苯基卟啉钯（PdTPP）和5,10,15,20-四苯基卟啉铂（PtTPP）构成三元体系，以期提高弱光上转换的效率。结果表明，具有适中空腔的-CD包络DTACl、与较长三线态寿命PdTPP构成的三元体系可明显提高上转换效率，原因是前者提高了发光剂的荧光量子产率、后者提高了分子间的三线态-三线态能量转移。用523 nm低功率（60 mW/cm2）半导体激光器激发上述三元体系，其上转换效率（UC）可达12.82%[这个效率在同类的研究中是什么水平？]。将获得的上转换荧光辐照Pt/WO3半导体粉末，可催化香豆素转化为7-羟基香豆素，表明弱光上转换在太阳能光催化合成方面具有潜在的应用价值。

Abstract:

Abstract：Low-powered up-conversion is a technique that low-energy light (long-wavelength) was absorbed by sensitizer and then high-energy light (short-wavelength) was emitted by the acceptor in the binary system, based on the triplet-triple annihilation mechanism. In order to enhance low-powered upconversion efficiency, a series of cyclodextrins (CD) such as -, - and -CD were firstly used to envelope the acceptor (2-chloro-9,10-xylene anthracene, DTACl) in the presence of sensitizer 5,10,15,20-tetraphenylporphyrin palladium (PdTPP) or 5,10,15,20-tetraphenylporphyrin platinum (PtTPP), which the ternary systems were formed. The results showed that -CD with appropriate cavity radius can effectively improve the fluorescence quantum efficiency (f) of DTACl and that sensitizer (PdTPP) with longer triplet lifetime is in favor of triplet-triplet energy transfer (TTT. As a result, the upconversion efficiency for ternary system (PdTPP/DTACl/-CD) was enhanced. Under the excitation of 523 nm diode laser (60 mW/cm2), bright green-to-blue upconversion was observed with the efficiency (UC) as high as 12.82%. With the help of Pt/WO3 photo-catalyst, the conversion from coumarin to 7-hydroxycoumarin was successfully achieved under the irradiation of our green-to-blue upconversion, indicating that low-powered up-conversion possesses potential application in the aspect of photocatalytic synthesis by solar energy.