We report the first example of a thermally activated delayed fluorescence (TADF) poly(dendrimer), composed of a norbornenyl-derived polymer backbone and dendritic side-chain chromophores comprising 2,3-dicyanopyrazino as the electron acceptor and a first-generation fluorenylcarbazole derivative as the electron donor. The TADF poly(dendrimer) homopolymer, with one dendritic side chain attached to each monomer unit, emitted deep-red light. The emission of the poly(dendrimer) was found to be red-shifted relative to the nonpolymeric doubly dendronized emitter composed of the same components. The simple dendrimer was found to have a solution photoluminescence quantum yield (PLQY) of around 70%. In contrast, the poly(dendrimer) had a PLQY of 9%, which was attributed to intramolecular interchromophore interactions. An interesting feature of the poly(dendrimer) was that oxygen did not quench the TADF emission. We found that the PLQY of the simple dendrimer decreased markedly in neat films, whereas that of the poly(dendrimer) did not, with both having a solid-state PLQY of around 10%. The results suggest that intrapolymer chromophore–chromophore interactions observed in solution for the poly(dendrimer) were similar to the intermolecular chromophore–chromophore interactions of the dendrimer in the solid state. Simple two-layer organic light-emitting diodes comprising nondoped films of the materials and an electron transport layer showed red emission with CIE coordinates of (x > 0.66, y < 0.34). The dendrimer-based device had a maximum external quantum efficiency of 2.4%, which is among the best for solution-processed deep-red emissive TADF-based OLEDs but in a simpler device architecture.

中文翻译：

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用于深红色OLED的溶液处理的基于树枝状聚合物的TADF材料

我们报告了一个热活化延迟荧光（TADF）聚（树状聚合物）的第一个例子，它由降冰片烯基衍生的聚合物主链和包含2,3-二氰基吡嗪并作为电子受体和第一代芴基咔唑衍生物的树状侧链生色团组成作为电子供体 TADF聚（树枝状聚合物）均聚物具有一个连接到每个单体单元的树枝状侧链，发出深红色光。相对于由相同组分组成的非聚合双树突状发射体，发现聚树枝状聚合物的发射发生红移。发现该简单的树枝状聚合物具有约70％的溶液光致发光量子产率（PLQY）。相比之下，聚树状聚合物的PLQY为9％，这归因于分子内发色团之间的相互作用。聚（树枝状大分子）的一个有趣特征是氧气不会猝灭TADF。我们发现，在纯净薄膜中，简单树枝状聚合物的PLQY显着降低，而聚树枝状聚合物的PLQY却没有显着降低，两者均具有约10％的固态PLQY。结果表明，在溶液中观察到的高分子（树枝状大分子）内的发色团与发色团之间的相互作用类似于固态下树枝状大分子的分子间发色团与发色团之间的相互作用。简单的两层有机发光二极管包括材料的非掺杂膜和电子传输层，其红色发射的CIE坐标为（两者的固态PLQY都在10％左右。结果表明，在溶液中观察到的高分子（树枝状大分子）内的发色团与发色团之间的相互作用类似于固态下树枝状大分子的分子间发色团与发色团之间的相互作用。简单的两层有机发光二极管包括材料的非掺杂膜和电子传输层，其红色发射的CIE坐标为（两者的固态PLQY都在10％左右。结果表明，在溶液中观察到的高分子（树枝状大分子）内的发色团与发色团之间的相互作用类似于固态下树枝状大分子的分子间发色团与发色团之间的相互作用。包含材料的非掺杂膜和电子传输层的简单两层有机发光二极管显示出红色发射，其CIE坐标为（x > 0.66，y <0.34）。基于树枝状聚合物的器件的最大外部量子效率为2.4％，这是固溶处理的基于深红色发射TADF的OLED的最佳值，但器件结构更为简单。