Thermally activated delayed fluorescence of carbazole-benzophenone dendrimers with bulky substituents
Thermally activated delayed fluorescence of carbazole-benzophenone dendrimers with bulky substituents
复制标题
具有大取代基的咔唑-二苯甲酮树枝状聚合物的热激活延迟荧光
DOI：
10.1039/d2py00255h
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发表时间：
2022
影响因子：
4.6
通讯作者：
Nakayama Akira
中科院分区：
文献类型：
--
作者：
Albrecht Ken;Hisamura Eri;Furukori Minori;Nakayama Yasuo;Hosokai Takuya;Nakao Kohei;Ikebe Hiroki;Nakayama Akira
合成了以二苯甲酮为核、末端带有大体积取代基的咔唑树枝状大分子，并研究了其热激活延迟荧光（TADF）性质。金刚烷（Ad）取代的树枝状聚合物显示绿色TADF发射，在纯膜中PLQY为40%。四苯基苯基（TPPh）取代的树枝状聚合物显示蓝色发光，在纯膜中PLQY为11%，但没有显示有效的TADF。树枝状大分子和树枝（片段）磷光测量表明，TPPh取代的咔唑树枝具有低的三重态能量。这将降低TADF的效率。此外，一个新的失活路径，由于大的自由度在旋转的TPPh取代基导致非辐射失活和淬灭的TADF发射。简单的末端修饰可以最大限度地减少分子间的相互作用，并调整TADF的开关，这为设计高效的TADF材料提供了见解。
Carbazole dendrimers with a benzophenone core and bulky terminal substituents were synthesized, and their thermally activated delayed fluorescence (TADF) properties were investigated. The adamantane (Ad) substituted dendrimer showed green TADF emission with a PLQY of 40% in the neat film. The tetraphenylphenyl (TPPh) substituted dendrimer showed blue emission with a PLQY of 11% in the neat film but did not show effective TADF. The dendrimer and dendron (fragment) phosphorescence measurement revealed that the TPPh substituted carbazole dendron has low triplet energy. This will reduce the TADF efficiency. Also a new deactivation path due to the large freedom in the rotation of TPPh substituents leads to non-radiative deactivation and quenches the TADF emission. Simple terminal modification can minimize the intermolecular interaction and tune the on–off of the TADF, which gives insights for designing efficient TADF materials.