Synthesis of triplet-triplet annihilation upconversion nanocapsules under protective conditions.
Synthesis of triplet-triplet annihilation upconversion nanocapsules under protective conditions.
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DOI：
10.1002/marc.201400670
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发表时间：
2015-06
影响因子：
4.6
通讯作者：
K. Katta;D. Busko;Y. Avlasevich;Rafael Muñoz‐Espí;S. Baluschev;K. Landfester
中科院分区：
文献类型：
--
作者：
K. Katta;D. Busko;Y. Avlasevich;Rafael Muñoz‐Espí;S. Baluschev;K. Landfester
三重态-三重态湮灭上转换（TTA-UC）纳米胶囊在氧保护条件下合成（即，完全黑暗和氩气气氛）。这些条件有助于排除在日光条件和富氧环境下合成期间产生的单线态氧引起的发射体分子的氧化。随后，保持所有其他实验条件相同，在保护条件下合成的样品显示出显著增加的UC效率。这些实验事实有力地支持了以下假设：从TTA-UC纳米胶囊中后部去除氧不足以获得可再现和可持续的UC结果。示意图显示了太阳光对单线态氧形成的影响及其对三重态-三重态湮灭上转换过程的影响。
Triplet-triplet annihilation upconversion (TTA-UC) nanocapsules are synthesized under oxygen-protective conditions (i.e., complete darkness and argon atmosphere) by free-radical miniemulsion polymerization. These conditions help to exclude the oxidation of the emitter molecules caused by singlet oxygen, generated during the synthesis at daylight conditions and oxygen-rich environment. Subsequently, keeping all the other experimental conditions the same, samples synthesized at protective conditions demonstrate substantially increased UC efficiency. These experimental facts strongly support the hypothesis that posterior removing of oxygen from TTA-UC nanocapsules is not sufficient to obtain reproducible and sustainable UC results. The schematic representation shows the influence of sunlight on the formation of singlet oxygen and its effect on the triplet-triplet annihilation upconversion process.