Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing, 100190, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Angew Chem Int Ed Engl. 2016 Nov 2;55(45):14023-14027. doi: 10.1002/anie.201607712. Epub 2016 Oct 10.
The spectroscopic and photophysical properties of organic materials in the solid-state are widely accepted as a result of their molecular packing structure and intermolecular interactions, such as J- and H-aggregation, charge-transfer (CT), excimer and exciplex. However, in this work, we show that Spe-F DIB cocrystals (SFCs) surprisingly retain the energy levels of photoluminescence (PL) states of Spe crystals, despite a significantly altered molecular packing structure after cocrystallization. In comparison, Npe-F DIB cocrystals (NFCs) with new spectroscopic states display different spectra and photophysical behaviors as compared with those of individual component crystals. These may be related to the molecular configuration in crystals, and we propose Spe as an "intramolecular emissive" material, thus providing a new viewpoint on light-emitting species of organic chromophores. Moreover, the nonlinear optical (NLO) properties of Npe and Spe are firstly demonstrated and modulated by cocrystallization. The established "molecule-packing-property" relationship helps to rationally control the optical properties of organic materials through cocrystallization.
固态有机材料的光谱和光物理性质被广泛认为是由于其分子堆积结构和分子间相互作用，如 J- 和 H-聚集、电荷转移 (CT)、激基缔合物和激基复合物。然而，在这项工作中，我们表明 Spe-F DIB 共晶（SFCs）尽管在共结晶后分子堆积结构发生了显著改变，但出人意料地保留了 Spe 晶体的光致发光（PL）状态的能级。相比之下，具有新光谱状态的 Npe-F DIB 共晶（NFCs）与单个组分晶体相比表现出不同的光谱和光物理行为。这可能与晶体中的分子构象有关，我们提出 Spe 是一种“分子内发射”材料，从而为有机发色团的发光物种提供了新的视角。此外，首次通过共结晶证明和调制了 Npe 和 Spe 的非线性光学（NLO）性质。所建立的“分子堆积-性质”关系有助于通过共结晶合理控制有机材料的光学性质。
