In this work we report how crucial is the correct design of the porphyrin sensitizers in Dye Sensitized Solar Cells (DSSCs). Only a single atom changeswitches-on the efficiency from 2-3% to over 10% under standard measurement conditions. We used the 2,1,3-benzothiadazole (BDT) group, as a π-conjugated linker, for the porphyrin LCVC01, a thiophene moiety for the porphyrin LCVC02 and also the furan group for the LCVC03 porphyrin, as molecular spacers between the BDT fragment and the molecule anchoring group, respectively. These three porphyrins were investigated for their application in DSSC devices. All the devices were characterized and found to achieve a record cell efficiency of 10.5% for LCVC02 but only 3.84% and 2.55% for LCVC01 and LCVC03 respectively. On one hand, the introduction of a thiophene, instead of a furan group, illustrates the importance of introducing a chemical group as a spacer, such as thiophene, between the BDT and the anchoring group. On the other hand, the selection of this group has to be correct because the change of a single atom increases the charge recombination rate and decreases the device performance. These changes can be rationalized by analyzing the dye dipoles and their interactions.
Two zinc-porphyrin sensitizers, 1a and 1b, bearing triphenylamine donor groups, were synthesized and their efficiencies measured in nanocrystalline TiO 2 dye sensitized solar cells employing iodide/tri-iodide and tris(1,10-phenanthroline) cobalt electrolytes. Optimized sensitization time for the TiO 2 photoanode was found to depend on the electrolyte employed: devices based on iodide/tri-iodide showed better efficiencies with shorter sensitization times (1.5 hours) whereas those based on tris(1,10-phenanthroline) cobalt showed better efficiencies with longer sensitization times (6 hours). From UV-Vis absorption spectra it is estimated that there is roughly twice as much dye loaded onto the TiO 2 film sensitized for 6 hours compared to the 1.5 hour film. Interfacial processes were probed using transient photovoltage, transient absorption and fluorescence lifetime measurements. The results indicate that sensitization time does not affect either dye regeneration or interfacial recombination processes in the presence of either electrolyte. However, sensitization time does have a considerable impact on device photocurrent, and moreover, the effect is different for the two electrolytes studied. This work demonstrates how device preparation must be tailored carefully depending on the electrolyte red/ox couple used.
The solar cells of third generation, which can be classified in hybrids and organics, are the target of uncountable studies and developments along the last few years. These cells present low fabrication cost, flexibility, lightness, and stability. In this work two new Zinc-porphyrin 1a and 1b, bearing triphenylamine donor groups were synthesized and their efficiencies measured in nanocrystalline TiO 2 dye sensitized solar cells employing iodide/tri-iodide and tris(1,10-phenanthroline) cobalt electrolytes. Optimized sensitization time for the TiO 2 photoanode was found to depend on the electrolyte employed: devices based on iodide/tri-iodide showed better efficiencies with shorter sensitization times (1.5 hours) whereas those based on tris(1,10-phenanthroline) cobalt showed better efficiencies with longer sensitization times (6 hours). From UV-Vis absorption spectra it is estimated that there is roughly twice as much dye loaded onto the TiO 2 film sensitized for 6 hours compared to the 1.5 hour film.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.