Enhanced energy transfer from diolefinic laser dyes to meso-tetrakis (4-sulfonatophenyl) porphyrin immobilized on silver nanoparticles: DFT, TD-DFT and spectroscopic studies

•Spectroscopic investigations of both ground and excited states of the dyes under the study.•Photophysical interactions between DOLDs and TPPS.•TD-DFT/DFT theoretical calculations and their matching with the measured spectra and proofing the partial positive charge on DOLDs.•Effect of negatively charged AgNPs on FRET from DOLDs to TPPS. The proposed enhancement mechanism is a kind of nano-immobilization.•Theoretical and experimental results are matched.