Unveiling the effect of TADF as an energy relay dye in fluorescence resonance energy transfer based solid-state dye-sensitized solar cells

Herein, the effect of thermally activated delayed fluorescence (TADF) material (4CzBN) as an energy donor (energy relay dye) has been studied using TVP208 as an energy acceptor in fluorescence resonance energy transfer (FRET) based solid state dye sensitized solar cell (SS-DSSC). The performances of the TVP208 dye sensitized SS-DSSCs were compared by systematically changing the concentrations (0.0, 0.05, 0.10 and 0.15 wt%) of donor molecule, 4CzBN. FRET-based SS-DSSC has achieved 5.17% power conversion efficiency (PCE) with 11.52 mAcm(-2) current density (Jsc) at 0.10 wt% of 4CzBN, which was 22% higher than that of the pristine SS-DSSC. The improvement in PCE performance could be ascribed to the enhanced light-harvesting property as demonstrated from the increased incident photon to current conversion efficiency (IPCE), which signifies the effect of FRET donor, 4CzBN. Detailed optical and electrochemical properties of the synthesized molecules have been analyzed and complemented with the density functional theory studies. (C) 2021 Elsevier B.V. All rights reserved.