School of Chemistry and Chemical Engineering Shanghai Key Lab of Electrical Insulation and Thermal Aging Shanghai Electrochemical Energy Devices Research Center, Shanghai Jiao Tong University, No. 800 Dongchuan Rd., Minhang District, Shanghai, 200240, China.
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids Institute of Chemistry, Beijing, 100190, China.
Chemphyschem. 2020 Jan 3;21(1):36-42. doi: 10.1002/cphc.201901024. Epub 2019 Dec 11.
Pure organic room-temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Herein, we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boosts the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5 % is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results will spur the future fabrication of nonconventional phosphors and advance the understanding of the underlying emission mechanism.
纯有机室温磷光（RTP）和非传统发光体的发光引起了越来越多的关注。然而，由于对发射机制的理解不够深入，要实现非传统发光体的高效 RTP 仍然具有挑战性。在本文中，我们提出了一种通过结合孤对电子、聚集和有效的电子相互作用来实现非传统发光体中高效 RTP 的策略。前者促进了自旋轨道耦合，从而促进了随后的系间窜越，而后者则缩小了能隙并稳定了三重态，从而协同提供了显著的 RTP。尿素及其衍生物的实验和理论结果验证了该设计原理。值得注意的是，从硫脲固体中获得了前所未有的高效 RTP，效率高达 24.5%。进一步的控制实验证明了通过空间离域对发射的关键作用。这些结果将激发未来对非传统荧光粉的制造，并推进对基础发射机制的理解。
