“…In the solid or aggregation state, the conjugated aromatic hydrocarbon tends to form excimer and/or exciplex due to the intermolecular interaction including π–π stacking, electrostatic attractions and van der Waals force, which, in most time, results in a drastic decrease of their luminescence efficiency. , Studies on the aggregation state of organic luminescence materials revealed that the aggregation morphology was dominated by molecular structure of the materials, , temperature, solvent, and other kinetic parameters. In varying solvent or temperature, different aggregation morphologies could be prepared, resulting in wide differences in luminescent properties. , As to the molecular structure modifying, the introduction of long-chained alkoxy could increase the solubility and rheological properties of conjugated molecule, and then improve the film-forming capability, leading to optimized spin-coated film morphology . Usually, as for one material, a more aggravated aggregation state led to red-shifted and broader absorption spectra …”