Liu Minghuan, Liu Yonggang, Peng Zenghui, Yang Chengliang, Mu Quanquan, Cao Zhaoliang, Ma Ji, Xuan Li
State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Materials (Basel). 2017 Jun 29;10(7):706. doi: 10.3390/ma10070706.
Systematic experiments were performed to investigate solvent-dependent morphology and aggregation of the semiconducting polymer film poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV), which was span-cast from nonaromatic strong polarity solvents tetrahydrofuran (THF), trichloromethane (TCM) and aromatic weak polarity solvents chlorobenzene (CB), toluene, and p-xylene. The results indicated that the conformation of the spin-cast MEH-PPV films with weak aggregation such as THF and TCM demonstrated excellent lasing emission performances because of inhibiting the fluorescence quenching induced by bi-molecule process. The Atomic Force Microscope (AFM) images confirmed the distinct morphologies of the spin-cast MEH-PPV films. The amplified spontaneous emission (ASE) was investigated in a simple asymmetric slab planar waveguide structure by methods of variable stripe length (VSL) and shifting excitation stripe (SES). The amplified spontaneous emission (ASE) experiments confirmed the distinct polymer chain conformation. The conformation, which preserved from the spin-cast process, indicated the distinct interactions between solvents and MEH-PPV polymer chains. The pure film spectra were performed to confirm the effect of distinct conformation on the material energy level. This work provides insights into the morphology and aggregation effect of the spin-cast polymer films on the performances of lasers.
进行了系统实验，以研究半导体聚合物薄膜聚2-甲氧基-5-(2'-乙基己氧基)-1,4-亚苯基亚乙烯基的溶剂依赖性形态和聚集情况，该薄膜是从非芳香族强极性溶剂四氢呋喃(THF)、三氯甲烷(TCM)以及芳香族弱极性溶剂氯苯(CB)、甲苯和对二甲苯旋涂而成的。结果表明，用THF和TCM等弱聚集性溶剂旋涂的MEH-PPV薄膜的构象，由于抑制了双分子过程引起的荧光猝灭，表现出优异的激光发射性能。原子力显微镜(AFM)图像证实了旋涂的MEH-PPV薄膜具有明显不同的形态。通过可变条纹长度(VSL)和移动激发条纹(SES)方法，在简单的不对称平板平面波导结构中研究了放大自发辐射(ASE)。放大自发辐射(ASE)实验证实了聚合物链构象的明显差异。旋涂过程中保留的构象表明了溶剂与MEH-PPV聚合物链之间存在明显不同的相互作用。进行了纯薄膜光谱实验，以确认不同构象对材料能级的影响。这项工作为旋涂聚合物薄膜的形态和聚集效应及其对激光性能的影响提供了见解。
