Delineating the effect of substituent and π-bridge flip on the photophysical properties of pyrene derivatives: answers from DFT/TD-DFT calculations. - Panneerselvam, Murugesan; Kathiravan, Arunkumar; Johnee Britto, Neethinathan; Krishnan, Shanmugam Murali; Velmurugan, Gunasekaran; Jaccob, Madhavan (Journal of Materials Science, 2022)