Hyperbranched Unsaturated Polyphosphates as a Protective Matrix for Long-Term Photon Upconversion in Air
Hyperbranched Unsaturated Polyphosphates as a Protective Matrix for Long-Term Photon Upconversion in Air
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DOI：
10.1021/ja5049412
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发表时间：
2014-08-06
影响因子：
15
通讯作者：
Wurm, Frederik R.
中科院分区：
文献类型：
--
作者：
Marsico, Filippo;Turshatov, Andrey;Wurm, Frederik R.
储存在有机分子的三重态中的能量，能够通过发射过程（磷光）或非发射过程（三重态-三重态转移）进行能量转移，在分子氧存在下主动耗散。原因是光激发的单线态氧具有很高的反应活性，因此体系中的光活性分子很快被氧化。氧化导致效率的进一步损失和各种不期望的副作用。在这项工作中，我们开发了一种结构多样的超支化不饱和聚（磷酸酯）库，其允许有效清除单线态氧，但不与基态的分子氧反应，即，三重态选择三重态-三重态湮灭光子上转换作为高度氧敏感的过程，作为对单线态氧猝灭的长期保护的证据，在环境条件下光子上转换的效率与在几种不饱和多磷酸盐中的无氧环境中相当。实验结果进一步相关的NMR光谱和理论计算证明的磷酸盐中心的重要性。这些结果为高效太阳能电池以及可持续太阳能上转换设备打开了一扇技术窗口，从而获得宽带太阳光激发光谱。
The energy stored in the triplet states of organic molecules, capable of energy transfer via an emissive process (phosphorescence) or a nonemissive process (triplet-triplet transfer), is actively dissipated in the presence of molecular oxygen. The reason is that photoexcited singlet oxygen is highly reactive, so the photoactive molecules in the system are quickly oxidized. Oxidation leads to further loss of efficiency and various undesirable side effects. In this work we have developed a structurally diverse library of hyperbranched unsaturated poly(phosphoester)s that allow efficient scavenging of singlet oxygen, but do not react with molecular oxygen in the ground state, i.e., triplet state. The triplet-triplet annihilation photon upconversion was chosen as a highly oxygen-sensitive process as proof for a long-term protection against singlet oxygen quenching, with comparable efficiencies of the photon upconversion under ambient conditions as in an oxygen-free environment in several unsaturated polyphosphates. The experimental results are further correlated to NMR spectroscopy and theoretical calculations evidencing the importance of the phosphate center. These results open a technological window toward efficient solar cells but also for sustainable solar upconversion devices, harvesting a broad-band sunlight excitation spectrum.