Abstract：
Current research of triplet-triplet annihilation upconversion (TTA-UC) faces difficulty such as overuse of organic solvents and quenching of excited triplet sensitizers by molecular oxygen. Herein, we propose an efficient and facile preparation strategy of TTA-UC microemulsion to overcome these issues. With simple device and short preparation process, air-stable TTA-UC with a high upconversion efficiency of 16.52% was achieved in microemulsion coassembled from TritonX114, tetrahydrofuran and upconverting chromophores (platinum octaethyl-porphyrin and 9,10-diphenylanthracene). This is comparable to the highest UC efficiency ever reported for TTA-UC microemulsion systems. The excellent UC performance of TX114-THF could be attributed to two perspectives. Firstly, small-size micelle accommodated chromophores up to high concentrations in organic phase, which promoted efficient molecular collision. Additionally, high absorbance at 532 nm ensured full use of excitation light, getting more long wavelength photons involved in the TTA-UC process. Moreover, air-stable TTA-UC also performed well in microemulsion with various surfactants, including nonionic surfactants (Tween 20, Tween 80, Triton X-110, Triton X-114), ionic surfactants (sodium dodecyl sulfate, cetyltrimethyl ammonium bromide) and block copolymers (pluronic F127, pluronic P123), through three conjectural assembly models according to the structural characteristics of surfactant molecules (concentrated, uncompacted and scattered). These discoveries could provide estimable reference for selection of surfactants in relevant fields of TTA-UC.
摘要：
三重态-三重态湮没上转换（TTA-UC）的当前研究面临诸如有机溶剂的过度使用和分子氧对激发的三重态敏化剂的猝灭等困难。在这里，为了克服这些问题，我们提出了一种高效，简便的TTA-UC微乳制备策略。设备简单，制备过程短，在由TritonX114，四氢呋喃和上转换发色团（铂八乙基卟啉和9,10-二苯基蒽）共组装的微乳液中，实现了空气稳定的TTA-UC，上转换效率高达16.52％。这与TTA-UC微乳液体系有史以来报道的最高UC效率相当。TX114-THF的优异UC性能可归因于两个方面。首先,小尺寸胶束容纳发色团在有机相中达到高浓度，这促进了有效的分子碰撞。此外,532nm处的高吸收率确保了激发光的充分利用，获得更多的长波长光子参与TTA-UC过程。此外，空气稳定的TTA-UC在具有各种表面活性剂的微乳液中也表现良好，包括非离子表面活性剂（吐温20，吐温80，TritonX-110，TritonX-114），离子表面活性剂(十二烷基硫酸钠，十六烷基三甲基溴化铵）和嵌段共聚物（pluronicF127，pluronicP123），根据表面活性剂分子的结构特征，通过三个猜想组装模型(浓缩，未压实和分散)。这些发现可为TTA-UC相关领域表面活性剂的选择提供参考。
