Photoelectrochemical Properties of Doubly β-Functionalized Porphyrin Sensitizers for Dye-Sensitized Nanocrystalline-TiO₂ Solar Cells

Abstract

Functionalized porphyrins at meso-and β-positions with different carboxylic acid groups were prepared to investigate electronic and photovoltaic properties as dye-sensitized nanocrystalline-TiO 2 solar cells. The electronic structures of the porphyrin macrocyclic core are strongly coupled with olefinic side chains so that the absorption spectrum exhibits largely broad and red-shifted Soret and Q-bands, especially up to 475 nm at the Soret band in a porphyrin doubly functionalized with malonic diacid groups. Among porphyrin derivatives prepared in this study, 2b-bdta-Zn exhibits the maximum overall conversion efficiency of 3.03% and the maximum incident photon to current efficiency of 60.1% in the Soret band region, superior to the others. From such photovoltaic performances, we can suggest that multiple pathways through olefinic side chains at two β-positions enhance the overall electron injection efficiency and the moderate distance between the porphyrin sensitizer and the TiO 2 semiconductor layer is important, retarding the charge recombination processes. As a consequence, these combined effects give rise to higher photovoltaic efficiency in photovoltaic regenerative solar cells.

A facile modification of g-C3N4 with enhanced photocatalytic activity for degradation of methylene blue

“…However, TiO 2 is able to drive the photocatalysis through excitement by only the ultraviolet light ( < 400 nm), accounting for about 4% of the sunlight, which greatly limits its practical applications [5]. Consequently, much effort has been made on the development of photocatalytic processes that efficiently utilized the visible light, including modification of TiO 2 with metals [6], non-metals [7], semiconductor oxides [8], and photo-sensitizers [9], or development of new type photocatalysts with high activity under a wide range of visible light [10,11].…”

Synthesis, Optical and Photovoltaic Properties of Porphyrin Dyes

“…Much work has been focused on modifying the molecular structure of porphyrin, including various metallation and substitution groups, as well as anchoring groups, and studying how this affects the photoelectrochemical properties of DSSCs (18,19). The power conversion efficiencies reported for porphyrin DSSCs to date are typically in the range of 0.5-3% and have recently been enhanced to 5-7% (16)(17)(18)(20)(21)(22)(23)(24)(25). Large inconsistencies exist among different groups, indicating that many factors that influence the performance of porphyrin DSSCs are not well understood.…”

Effect of the anchoring group in porphyrin sensitizers: phosphonate versus carboxylate linkages

“…27 Among them, porphyrins doubly functionalized with a dienic fragment bearing 2 carboxylate groups 19 demonstrate the higher photovoltaic performances (Table 4). The authors observed H-type interactions in porphyrin systems indicating highly packed monolayers of porphyrins on the TiO 2 surface.…”