Long-Living Optical Gain Induced by Solvent Viscosity in a PushPull Molecule

A new push-pull molecule has been characterized in solution by ultrafast pump-probe combined with DFT and TDDFT calculations. Comparison studies in viscous and non-viscous environment shed more light on the Twisted Intramolecular Charge Transfer mechanism. Long-living optical gain is found when this mechanism is inhibited, highlighting the role of the environment rigidity in the design of materials for photonic applications.