Anantharaman Surendra B, Kohlbrecher Joachim, Rainò Gabriele, Yakunin Sergii, Stöferle Thilo, Patel Jay, Kovalenko Maksym, Mahrt Rainer F, Nüesch Frank A, Heier Jakob
Laboratory for Functional Polymers Empa Swiss Federal Laboratories for Materials Science and Technology Überlandstrasse 129 Dübendorf CH-8600 Switzerland.
Institut des Matériaux École Polytechnique Fédérale de Lausanne EPFL Station 12 Lausanne CH-1015 Switzerland.
Adv Sci (Weinh). 2021 Jan 4;8(4):1903080. doi: 10.1002/advs.201903080. eCollection 2021 Feb.
Supramolecular assemblies from organic dyes forming J-aggregates are known to exhibit narrowband photoluminescence with full-width at half maximum of ≈9 nm (260 cm). Applications of these high color purity emitters, however, are hampered by the rather low photoluminescence quantum yields reported for cyanine J-aggregates, even when formed in solution. Here, it is demonstrated that cyanine J-aggregates can reach an order of magnitude higher photoluminescence quantum yield (increase from 5% to 60%) in blend solutions of water and alkylamines at room temperature. By means of time-resolved photoluminescence studies, an increase in the exciton lifetime as a result of the suppression of non-radiative processes is shown. Small-angle neutron scattering studies suggest a necessary condition for the formation of such highly emissive J-aggregates: the presence of a sharp water/amine interface for J-aggregate assembly and the coexistence of nanoscale-sized water and amine domains to restrict the J-aggregate size and solubilize monomers, respectively.
已知由形成J聚集体的有机染料构成的超分子组装体表现出窄带光致发光，其半高宽约为9纳米（260厘米）。然而，这些高色纯度发射体的应用受到了花菁J聚集体所报道的相当低的光致发光量子产率的阻碍，即使是在溶液中形成时也是如此。在此，证明了花菁J聚集体在室温下于水和烷基胺的混合溶液中可达到高一个数量级的光致发光量子产率（从5%提高到60%）。通过时间分辨光致发光研究表明，由于非辐射过程的抑制，激子寿命增加。小角中子散射研究表明形成这种高发射性J聚集体的一个必要条件：存在用于J聚集体组装的尖锐水/胺界面以及纳米级尺寸的水和胺域共存，分别用于限制J聚集体尺寸和溶解单体。
