Enhanced indoor photovoltaic efficiency of 40% in dye-sensitized solar cells using cocktail starburst triphenylamine dyes and dual species copper electrolyte

Recombination is the most critical process that controls the photovoltaic performance in dye-sensitized solar cells (DSCs). Herein, we successfully introduced a new triphenylamine-based starburst photosensitizer, RJ-C6 [3-(4-(bis(4-((2,4-bis(hexyloxy)phenyl)ethynyl)phenyl)amino)phenyl)-2-cyanoacrylic acid] grafted with extended alkyl groups and phenylethynyl bridges capable of arresting recombination more effectively and realizing enhanced light harvesting through improved conjugation and rigidity. Using a cocktail mixture of RJ-C6 with XY1b dye and asymmetric dual species copper (II/I) electrolyte, we realized an efficiency of 10.40% under standard AM 1.5G, 100 mW/cm2 irradiation. Strikingly, the same co-sensitized devices exhibited a panchromatic absorption overlapping the entire fluorescent light spectra, delivering an efficiency of 35% under 100 lux, 37% under 1000 lux and a record PCE of 40% under 4000 lux fluorescent light illumination, taking DSC one step closer to being used as an attractive successor for indoor photovoltaic applications.