Gao Can, Zhang Bolong, Hall Christopher R, Li Li, Chen Yeqin, Zeng Yi, Smith Trevor A, Wong Wallace W H
ARC Centre of Excellence in Exciton Science, School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Australia.
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China.
Phys Chem Chem Phys. 2020 Mar 18;22(11):6300-6307. doi: 10.1039/c9cp06311k.
Improving the efficiency of triplet fusion upconversion (TF-UC) in the solid-state is still challenging due to the aggregation and phase separation of chromophores. In this work, two 9,10-diphenylanthracene (DPA) derivatives based on the modification of the 9,10-phenyl rings with bulky isopropyl groups (bDPA-1 and bDPA-2) were used as emitters. By using platinum octaethylporphyrin (PtOEP) as the sensitizer, TF-UC performance was comprehensively investigated in 3 media: toluene solution, polyurethane thin film and nano/micro-crystals in a polyvinyl alcohol matrix. Only a small difference in upconversion efficiency between the bulky DPAs and the DPA reference was observed in toluene solution and polyurethane thin film. However, a large improvement of TF-UC quantum yield was achieved in bDPA-2/PtOEP crystals (ΦUC = (0.92 ± 0.05)%) with a low excitation intensity threshold (52 mW cm-2) compared to that of DPA/PtOEP crystals (ΦUC = (0.09 ± 0.03)%). This difference was largely attributed to improved dispersibility of the PtOEP sensitizer in the bDPA-2 emitter crystals. The bulky DPAs also show excellent stability under UV irradiation with exposure to oxygen compared to DPA. These results provide a strategy for developing efficient solid-state TF-UC systems based on nano/micro-particles of emitter-sensitizer mixtures.
由于发色团的聚集和相分离，提高固态三重态融合上转换（TF-UC）的效率仍然具有挑战性。在这项工作中，两种基于用庞大的异丙基修饰9,10-苯环的9,10-二苯基蒽（DPA）衍生物（bDPA-1和bDPA-2）被用作发光体。通过使用八乙基铂卟啉（PtOEP）作为敏化剂，在三种介质中全面研究了TF-UC性能：甲苯溶液、聚氨酯薄膜以及聚乙烯醇基质中的纳米/微晶。在甲苯溶液和聚氨酯薄膜中，仅观察到庞大的DPA与DPA参比物之间的上转换效率存在微小差异。然而，与DPA/PtOEP晶体（ΦUC = (0.09 ± 0.03)%）相比，bDPA-2/PtOEP晶体在低激发强度阈值（52 mW cm-2）下实现了TF-UC量子产率的大幅提高（ΦUC = (0.92 ± 0.05)%）。这种差异很大程度上归因于PtOEP敏化剂在bDPA-2发光体晶体中的分散性得到改善。与DPA相比，庞大的DPA在暴露于氧气的紫外光照射下也表现出优异的稳定性。这些结果为基于发射体-敏化剂混合物的纳米/微粒开发高效固态TF-UC系统提供了一种策略。
