Design Strategy for Ag(I)-Based Thermally Activated Delayed Fluorescence Reaching an Efficiency Breakthrough
Design Strategy for Ag(I)-Based Thermally Activated Delayed Fluorescence Reaching an Efficiency Breakthrough
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DOI：
10.1021/acs.chemmater.6b05175
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发表时间：
2017-02
影响因子：
8.6
通讯作者：
M. Shafikov;Alfiya F. Suleymanova;R. Czerwieniec;H. Yersin
中科院分区：
文献类型：
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作者：
M. Shafikov;Alfiya F. Suleymanova;R. Czerwieniec;H. Yersin
提出了一种用于开发热激活延迟荧光（TADF）的Ag（I）基材料的设计策略。虽然Ag（I）配合物通常不显示TADF，但所设计的材料Ag（dbp）（P2-nCB）[dbp = 2，9-二正丁基-1，10-菲咯啉，P2-nCB =巢式碳硼烷-双（二苯基膦）]显示出TADF效率突破，其在ΦPL = 100%的量子产率下表现出τ（TADF）= 1.4 μs的发射衰减时间。这是三个优化参数的结果。(i)强供电子负电荷的P2-nCB配体使4d轨道不稳定，并导致具有MLL′CT特征的低位电荷（CT）态，其中L和L′是两个不同的配体，从而在最低单重态S1和三重态T1之间产生ΔE（S1-T1）= 650 cm-1（80 meV）的小能量分离。(ii)实验和含时密度泛函表明，S1 → S 0跃迁的容许度比其它TADF金属配合物高1个数量级以上。
A design strategy for the development of Ag(I)-based materials for thermally activated delayed fluorescence (TADF) is presented. Although Ag(I) complexes usually do not show TADF, the designed material, Ag(dbp)(P2-nCB) [dbp = 2,9-di-n-butyl-1,10-phenanthroline, and P2-nCB = nido-carborane-bis(diphenylphosphine)], shows a TADF efficiency breakthrough exhibiting an emission decay time of τ(TADF) = 1.4 μs at a quantum yield of ΦPL = 100%. This is a consequence of three optimized parameters. (i) The strongly electron-donating negatively charged P2-nCB ligand destabilizes the 4d orbitals and leads to low-lying charge (CT) states of MLL′CT character, with L and L′ being the two different ligands, thus giving a small energy separation between the lowest singlet S1 and triplet T1 state of ΔE(S1–T1) = 650 cm–1 (80 meV). (ii) The allowedness of the S1 → S0 transition is more than 1 order of magnitude higher than those found for other TADF metal complexes, as shown experimentally and by time-dependent density functi...