Institute for Advanced Materials, South China Normal University, Guangzhou, 510006, China.
CNRS UMR 6200, MOLTECH-Anjou, University of Angers, 2 Bd Lavoisier, 49045, Angers, France.
Sci Rep. 2017 Aug 16;7(1):8317. doi: 10.1038/s41598-017-08606-6.
The synthesis of a molecule constituted of two diarylamine-based push-pull chromophores covalently linked via their nitrogen atom is described. Comparison of the electronic properties with the parent monomer shows that dimerization has negligible influence on the electronic properties of the molecule but exerts a dramatic impact on the capacity of the material to self-reorganize. Application of thermal annealing to thin films induces the crystallization under original morphologies, a process accompanied by a partial bleaching of the absorption in the visible range and by a huge increase of hole-mobility. X-ray diffraction data on single crystals reveal the presence of π-stacked organization with a non-centrosymmetric co-facial arrangement of the dipoles which leads to intrinsic 2 order bulk NLO properties of thin films as evidenced by second harmonic generation under 800 nm laser light. The implications of this thermally induced crystallization on the photovoltaic properties of the material are discussed on the basis of preliminary results obtained on simple bilayer organic solar cells.
本文描述了一种由两个二芳基脒基推-拉发色团通过氮原子共价连接而成的分子的合成。与母体单体的电子性质进行比较表明，二聚化对分子的电子性质几乎没有影响，但对材料自组织的能力有显著影响。将热退火应用于薄膜会在原始形态下诱导结晶，这一过程伴随着可见光范围内吸收的部分漂白和空穴迁移率的大幅增加。单晶的 X 射线衍射数据表明存在π-堆积组织，偶极子的非中心对称面对面排列，导致薄膜具有内在的二阶非线性光学性质，这一点在 800nm 激光下的二次谐波产生中得到了证明。基于简单的双层有机太阳能电池获得的初步结果，讨论了这种热诱导结晶对材料光伏性能的影响。
