Dipartimento di Chimica, Università di Perugia, 06123 Perugia, Italy.
Photochem Photobiol Sci. 2014 Jan;13(1):48-61. doi: 10.1039/c3pp50318f. Epub 2013 Nov 5.
The triplet-triplet annihilation based up-conversion process, involving a platinum octaethyl-porphyrin (PtOEP) as a sensitizer and tetraphenyl-pyrene (TPPy) as an emitter, has been investigated in homogeneous solutions of toluene, bromobenzene and anisole, and oil-in-water microemulsions of the TX-100 surfactant, where toluene constitutes the non-polar phase. In homogeneous solutions, the highest up-conversion quantum yield (of the order of 20%) has been achieved in toluene, being the solvent that has the lowest viscosity among those explored. The up-conversion emission from the PtOEP-TPPy pair has been then investigated in a toluene based oil-in-water microemulsion at three different concentrations of the solutes, showing quantum yields up to the order of 1%, under the same irradiation conditions, but different deoxygenating procedures. The results herein reported might represent a good starting point for a future investigation in microheterogeneous systems. An optimization of the microemulsion composition, in terms of surfactant, co-surfactant and toluene concentrations, could allow us to increase the sensitizer and emitter concentrations and set up the best operative conditions to obtain even higher up-conversion efficiencies.
三重态-三重态湮灭上转换过程，涉及八乙基铂卟啉（PtOEP）作为敏化剂和四苯基芘（TPPy）作为发射体，已在甲苯、溴苯和苯甲醚的均相溶液以及 TX-100 表面活性剂的油包水乳状液中进行了研究，其中甲苯构成非极性相。在均相溶液中，在研究的溶剂中粘度最低的甲苯中实现了最高的上转换量子产率（约 20%）。然后，在三种不同溶质浓度下，在基于甲苯的油包水乳状液中研究了 PtOEP-TPPy 对的上转换发射，在相同的辐照条件下，但不同的除氧程序下，量子产率高达 1%左右。本文报道的结果可能为微多相体系的未来研究提供一个良好的起点。通过优化表面活性剂、助表面活性剂和甲苯浓度的微乳液组成，可以提高敏化剂和发射体的浓度，并设定最佳的操作条件，以获得更高的上转换效率。
