Pyrene-substituted ethenes: aggregation-enhanced excimer emission and highly efficient electroluminescence
作者:Zujin Zhao、Shuming Chen、Jacky W. Y. Lam、Zhiming Wang、Ping Lu、Faisal Mahtab、Herman H. Y. Sung、Ian D. Williams、Yuguang Ma、Hoi Sing Kwok、Ben Zhong Tang
DOI:10.1039/c0jm04449k
日期:——
Pyrene-substituted ethenes, 1,2,2-tripheny-1-pyrenylethene (TPPyE) and 1,2-diphenyl-1,2-dipyrenylethene (DPDPyE), are synthesized and characterized. Whereas they are weakly emissive in solution they become strong emitters when aggregated in the condensed phase. In contrast to the general observation that excimer formation quenches the light emission of fluorophores, TPPyE and DPDPyE exhibit efficient excimer emissions in the solid state with high fluorescence quantum yields up to 100%. The π–π intermolecular interactions between the pyrene rings, coupled with multiple C–H⋯π hydrogen bonds, efficiently restrict intramolecular rotations, which block the nonradiative energy decay channel, and hence make the dye molecules highly emissive in the solid state. Non-doped organic light-emitting diodes using TPPyE and DPDPyE as emitters are fabricated, which give green light at low turn-on voltages (down to 3.2 V) with maximum luminance and power, current, and external quantum efficiencies of 49830 cd m−2, 9.2 lm W−1, 10.2 cd A−1 and 3.3%, respectively.
合成并鉴定了芘取代的乙烯--1,2,2-三苯基-1-芘(TPPyE)和 1,2-二苯基-1,2-二芘(DPDPyE)。虽然它们在溶液中的发射性很弱,但当它们在凝聚相中聚集时,就会变成强发射体。与一般观察到的准分子形成会淬灭荧光团的光发射不同,TPPyE 和 DPDPyE 在固态下表现出高效的准分子发射,荧光量子产率高达 100%。芘环之间的 π-π 分子间相互作用加上多个 C-H⋯π 氢键,有效地限制了分子内旋转,阻断了非辐射能量衰减通道,从而使染料分子在固态下具有很高的发射率。以 TPPyE 和 DPDPyE 为发光体制作的非掺杂有机发光二极管在低开启电压(低至 3.2 V)下发出绿光,具有最大亮度,功率、电流和外部量子效率分别为 49830 cd m-2、9.2 lm W-1、10.2 cd A-1 和 3.3%。