Probing the Excited State Photophysics of an Anthraquinone Based Dye in Solution and LB Films.

The photophysical properties of an anthraquinone based dye, Solvent Green 3 (SG3) were investigated in chloroform solution and stearic acid supported Langmuir-Blodgett films (SG-LB) by steady state and time-resolved spectroscopic techniques. Both steady state and time-resolved studies were performed for SG3 in chloroform solution (1 µM) whereas only steady-state measurements were performed for the SG-LB films. The studies revealed that the photodynamics of SG3 are guided by deexcitation of energetically separated conformers and aggregates of SG3, namely the closed form (CF) and open form (OF) in solution. However, in SG-LB, the OF dominates the photophysical properties. The current report sheds light on the effect of conformational confinement on the photophysical properties of organic dye molecules, thereby enabling better understanding of photo behaviour of small organic molecules.