Sensitized triplet–triplet‐annihilation‐based photon upconversion (TTA‐UC) permits the conversion of light into radiation of higher energy and involves a sequence of photophysical processes between two dyes. In contrast to other upconversion schemes, TTA‐UC allows the frequency shifting of low‐intensity light, which makes it particularly suitable for solar‐energy harvesting technologies. High upconversion yields can be observed for low viscosity solutions of dyes; but, in solid materials, which are better suited for integration in devices, the process is usually less efficient. Here, it is shown that this problem can be solved by using transparent nanodroplet‐containing polymers that consist of a continuous polymer matrix and a dispersed liquid phase containing the upconverting dyes. These materials can be accessed by a simple one‐step procedure that involves the free‐radical polymerization of a microemulsion of hydrophilic monomers, a lipophilic solvent, the upconverting dyes, and a surfactant. Several glassy and rubbery materials are explored and a range of dyes that enable TTA‐UC in different spectral regions are utilized. The materials display upconversion efficiencies of up to ≈15%, approaching the performance of optimized oxygen‐free reference solutions. The data suggest that the matrix not only serves as mechanically coherent carrier for the upconverting liquid phase, but also provides good protection from atmospheric oxygen.

中文翻译：

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含纳米液滴的聚合物可实现高效的低功率光上转换

基于三重态三重态-三重态an灭的光子上转换（TTA-UC）可以将光转换为更高能量的辐射，并且涉及两种染料之间的一系列光物理过程。与其他上变频方案相比，TTA-UC允许低强度光的频移，这使其特别适合于太阳能收集技术。对于低粘度的染料溶液，可以观察到较高的上转换率。但是，在更适合集成到设备中的固体材料中，该过程通常效率较低。在此表明，可以通过使用包含透明纳米滴的聚合物解决此问题，该聚合物由连续的聚合物基质和包含上转换染料的分散液相组成。这些材料可以通过简单的一步过程来获得，该过程涉及亲水性单体，亲脂性溶剂，上转换染料和表面活性剂的微乳液的自由基聚合。对几种玻璃状和橡胶状材料进行了探索，并使用了使TTA-UC处于不同光谱区域的一系列染料。这些材料的上转换效率高达≈15％，接近优化的无氧参考溶液的性能。数据表明，基体不仅充当上转换液相的机械相干载体，而且还提供了良好的保护免受大气中氧气的影响。对几种玻璃状和橡胶状材料进行了探索，并使用了使TTA-UC处于不同光谱区域的一系列染料。这些材料的上转换效率高达≈15％，接近优化的无氧参考溶液的性能。数据表明，基体不仅充当上转换液相的机械相干载体，而且还提供了良好的保护免受大气中氧气的影响。对几种玻璃状和橡胶状材料进行了探索，并使用了使TTA-UC处于不同光谱区域的一系列染料。这些材料的上转换效率高达≈15％，接近优化的无氧参考溶液的性能。数据表明，基体不仅充当上转换液相的机械相干载体，而且还提供了良好的保护免受大气中氧气的影响。