Yang Rui, Hu Zhijia, Li Yaxin, Xia Jiangying, Ma Jiajun, Yang Junxiao
State Key Laboratory of Environment-friendly Energy Materials, School of Material Science and Engineering, Southwest University of Science and Technology Mianyang 621010 China
School of Instrument Science and Opto-Electronics Engineering, Hefei University of Technology Hefei Anhui 230009 P. R. China.
RSC Adv. 2020 Jan 14;10(5):2437-2447. doi: 10.1039/c9ra09950f.
Dye doped organic thin films with controllable molecular aggregation and emission properties are of broad interest to the scientific community owing to their large number of potential applications in physics, chemistry, and materials science. Here, a spray coating method was used to prepare perylenebisimides (PBI) doped polymer films. In this study, the effects of the dye concentration, polymer matrix, solvent, and casting process on the optical properties of the resulting films were studied. The aggregation of the PBI into monomer, dimer, and oligomer forms, was rapidly and simply controlled based on the concentration dependence of PBI. The molecular aggregation mechanism in the film forming process for PBI doped polystyrene (PS) was further analyzed by computer simulations. The blends rapidly reached their lowest Gibbs free energy owing to the "frozen" polymer chains and confinement of PBI, molecules with different aggregation states. Therefore, the PBIs/PS films prepared under different conditions had different fluorescent lifetimes and absolute quantum yields. Narrow emission, amplified spontaneous emission (ASE) and random lasing (RL) were observed in PBI doped PS films when photo-pumped at 532 nm in transmittance and waveguide modes, respectively. A lower ASE and RL threshold were obtained for PS films doped with monomeric PBI than those in other aggregation states. Moreover, the solvent use in film deposition greatly influenced the emission properties of the PS films by altering their microstructures. These results indicate potential applications for spray coated dye/polymer films in organic solid-state lasers.
由于在物理、化学和材料科学等领域具有大量潜在应用，具有可控分子聚集和发射特性的染料掺杂有机薄膜引起了科学界的广泛关注。在此，采用喷雾涂层法制备了苝酰亚胺（PBI）掺杂的聚合物薄膜。在本研究中，研究了染料浓度、聚合物基质、溶剂和流延工艺对所得薄膜光学性能的影响。基于PBI的浓度依赖性，可快速、简单地控制PBI聚集成单体、二聚体和低聚物形式。通过计算机模拟进一步分析了PBI掺杂聚苯乙烯（PS）成膜过程中的分子聚集机制。由于“冻结”的聚合物链以及不同聚集态分子PBI的限制，共混物迅速达到其最低吉布斯自由能。因此，在不同条件下制备的PBIs/PS薄膜具有不同的荧光寿命和绝对量子产率。当分别在透射率和波导模式下以532nm光泵浦时，在PBI掺杂的PS薄膜中观察到窄发射、放大自发发射（ASE）和随机激光（RL）。掺杂单体PBI的PS薄膜的ASE和RL阈值低于其他聚集态的薄膜。此外，薄膜沉积中使用的溶剂通过改变其微观结构极大地影响了PS薄膜的发射特性。这些结果表明喷雾涂层染料/聚合物薄膜在有机固态激光器中的潜在应用。
