Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials.
Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials.
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DOI：
10.1038/ncomms9947
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发表时间：
2015-12-02
影响因子：
16.6
通讯作者：
Kim J
中科院分区：
文献类型：
--
作者：
Kwon MS;Yu Y;Coburn C;Phillips AW;Chung K;Shanker A;Jung J;Kim G;Pipe K;Forrest SR;Youk JH;Gierschner J;Kim J
不含金属的有机磷光材料是主要使用的有机金属磷光体的有吸引力的替代品，但通常较暗并且相对罕见，因为在没有重金属原子的情况下，自旋轨道耦合效率较低，并且磷光通常不能与无辐射弛豫过程竞争。在这里，我们提出了一个通用的设计规则和方法，以有效地减少无辐射跃迁，从而大大提高磷光效率的无金属有机材料在各种无定形聚合物基质，基于嵌入的磷光体附近的分子运动的限制。磷光体和聚合物基质之间经由Diels-Alder点击化学的共价交联被设计为一种方法。用这种方法在各种聚合物基质中观察到磷光量子效率的急剧增加，这是大约。比不具有这种共价键的磷光体掺杂的聚合物体系高2 - 5倍。 由纯有机组分制成的磷光体材料通常比其有机金属对应物效率低。在这里，作者报告了一种通过共价连接到聚合物基质中减少无辐射跃迁来提高无金属材料磷光效率的策略。
Metal-free organic phosphorescent materials are attractive alternatives to the predominantly used organometallic phosphors but are generally dimmer and are relatively rare, as, without heavy-metal atoms, spin–orbit coupling is less efficient and phosphorescence usually cannot compete with radiationless relaxation processes. Here we present a general design rule and a method to effectively reduce radiationless transitions and hence greatly enhance phosphorescence efficiency of metal-free organic materials in a variety of amorphous polymer matrices, based on the restriction of molecular motions in the proximity of embedded phosphors. Covalent cross-linking between phosphors and polymer matrices via Diels–Alder click chemistry is devised as a method. A sharp increase in phosphorescence quantum efficiency is observed in a variety of polymer matrices with this method, which is ca. two to five times higher than that of phosphor-doped polymer systems having no such covalent linkage. Phosphorescent materials made of purely organic components are typically less efficient than their organometallic counterparts. Here, the authors report a strategy to improve the phosphorescence efficiency of metal-free materials by reducing radiationless transitions by covalently linking into a polymer matrix.