Zhang Yuefa, Zhang Shiguo, Liu Guanyu, Sun Qikun, Xue Shanfeng, Yang Wenjun
Key Laboratory of Rubber-plastics of Ministry of Education/Shandong Provincial Key Laboratory of Rubber-plastics, School of Polymer Science & Engineering, Qingdao University of Science &Technology Qingdao China.
Chem Sci. 2023 Apr 19;14(19):5177-5181. doi: 10.1039/d3sc01276j. eCollection 2023 May 17.
Organic-doped polymers and room-temperature phosphorescence (RTP) mechanisms have been widely reported. However, RTP lifetimes >3 s are rare and RTP-enhancing strategies are incompletely understood. Herein, we demonstrate a rational molecular doping strategy to obtain ultralong-lived, yet bright RTP polymers. The n-π* transitions of boron- and nitrogen-containing heterocyclic compounds can promote a triplet-state population, and the grafting of boronic acid onto polyvinyl alcohol can inhibit molecular thermal deactivation. However, excellent RTP properties were achieved by grafting 1-0.1% (-phenylcarbazol-2-yl)-boronic acid rather than (2-/3-/4-(carbazol-9-yl)phenyl)boronic acids to afford record-breaking ultralong RTP lifetimes up to 3.517-4.444 s. These results showed that regulation of the interacting position between the dopant and matrix molecules to directly confine the triplet chromophore could more effectively stabilize triplet excitons, disclosing a rational molecular-doping strategy for achieving polymers with ultralong RTP. Based on the energy-donor function of blue RTP, an ultralong red fluorescent afterglow was demonstrated by co-doping with an organic dye.
有机掺杂聚合物和室温磷光（RTP）机制已有广泛报道。然而，RTP寿命大于3秒的情况很少见，且RTP增强策略尚未完全明晰。在此，我们展示了一种合理的分子掺杂策略，以获得超长寿命且明亮的RTP聚合物。含硼和氮的杂环化合物的n-π*跃迁可促进三重态粒子数的增加，且将硼酸接枝到聚乙烯醇上可抑制分子热失活。然而，通过接枝1-0.1%的（-苯基咔唑-2-基）硼酸而非（2-/3-/4-（咔唑-9-基）苯基）硼酸，实现了优异的RTP性能，获得了高达3.517-4.444秒的破纪录超长RTP寿命。这些结果表明，调节掺杂剂与基质分子之间的相互作用位置以直接限制三重态发色团，可更有效地稳定三重态激子，揭示了一种实现具有超长RTP聚合物的合理分子掺杂策略。基于蓝色RTP的能量供体功能，通过与有机染料共掺杂展示了超长红色荧光余辉。
