Enhanced light harvesting in mesoporous TiO2/P3HT hybrid solar cells using a porphyrin dye

We report panchromatic light harvesting in hybrid TiO2/P3HT photovoltaic devices using a porphyrin dye that complements the light absorption of P3HT. The high short circuit photocurrent (12.1 mA cm(-2)) obtained is found to be due, in part, to Forster resonance energy transfer from the P3HT to the dye

Design and characterization of alkoxy-wrapped push-pull porphyrins for dye-sensitized solar cells

Three alkoxy-wrapped push-pull porphyrins were designed and synthesized for dye-sensitized solar cell (DSSC) applications. Spectral, electrochemical, photovoltaic and electrochemical impedance spectroscopy properties of these porphyrin sensitizers were well investigated to provide evidence for the molecular design

Porphyrin-Perylene Dyes for Dye-Sensitized Solar Cells

Two novel porphyrin-perylene dyads 1 and 2 for DSSC applications have been synthesized. The absorption band of the perylene fills up the trough between the Soret and Q bands of the porphyrin, leading to an increase in the absorption efficiency of the dye. The highly conjugated acetylenic bridge mediates strong electronic coupling between the porphyrin and perylene units and results in the extension of it-conjugation of the porphyrin ring. The Soret and Q bands are broadened and red-shifted and the light-harvesting effect is thus improved. We propose that energy transfer occurs from the photoexcited perylene to porphyrin for dyad 1 whereas energy transfer proceeds from the excited porphyrin to perylene for dyad 2. Our studies show that multichromophoric dyes used for DSSC can be designed in a rational manner with predictable photophysical behavior and efficient light-harvesting properties, but the efficiency of the energy transfer process in a consecutive model needs to be controlled for a significant improvement of the cell performance using perylene-porphyrin sensitizers

Control of Dye Aggregation and Electron Injection for Highly Efficient Porphyrin Sensitizers Adsorbed on Semiconductor Films with Varying Ratios of Coadsorbate

We report the photovoltaic performances and kinetics of femtosecond fluorescence for three zinc-porphyrin sensitizers (YD0-YD2) coadsorbed with chenodeoxycholic acid (CDCA) at three molar ratios on nanocrystalline semiconductor (TiO(2) or Al(2)O(3)) films. The addition of CDCA improved the efficiencies of YD0 and YD1 so that their maximum performance occurred at a dye/CDCA ratio of 1:2, but the presence of CDCA had a negative effect for YD2. Porphyrin aggregation on TiO(2) surfaces not only accelerates the rate of intermolecular energy transfer but also increases the rate of interfacial electron injection, so that the electron injection yields (Phi(inj)) are balanced by these two important factors. As a result, Phi(inj) increased slightly with increasing amount of CDCA for both YD0 and YD1, but decreased for YD2; for this reason, the presence of CDCA failed to improve the photovoltaic performance for YD2, unlike for YD0 and YD1. The cell performances were optimized on TiO(2) films of similar to 10-mu m thickness with a scattering layer of similar to 4-mu m thickness: the efficiencies 4 if power conversion of YD1 and YD2 are slightly smaller than, but near, that of N719, being 6.5% and 6.8%, respectively, compared to 7.3%. Without a scattering layer on the films, the performance of N719 was degraded significantly (6.3%), whereas the efficiencies of YD1 and YD2 decreased only slightly (6.4% and 6.6%), making this series of green sensitizers promising candidates for future light-penetrable photovoltaic applications

Synthesis and characterization of diporphyrin sensitizers for dye-sensitized solar cells

Novel porphyrin dimers with broad and strong absorption in the visible and/or near IR regions have been synthesized; the meso-meso-linked porphyrin dimer (YDD1) exhibited the best photovoltaic performance with power conversion efficiency 5.2% under AM 1.5G one solar illumination

Design and characterization of highly efficient porphyrin sensitizers for green see-through dye-sensitized solar cells

YD12 (eta = 6.7%) is a green sensitizer remarkable for its outstanding cell performance beyond that of N719 (eta = 6.1%) with no added scattering layer; the additional scattering layer assists N719 in promoting the efficiency in the red shoulder of the spectrum, but has only a small effect on the improvement of the cell performance for porphyrins

Design and characterization of porphyrin sensitizers with a push-pull framework for highly efficient dye-sensitized solar cells

Novel porphyrin dyes YD14-YD17 with a push-pull framework were synthesized for dye-sensitized solar cells (DSSC); their spectral, electrochemical and photovoltaic properties were investigated. The absorption bands of these porphyrin dyes are broadened and red-shifted upon introduction of electron-donating groups (EDG) to the meso-positions via extension of p-conjugation. Electrochemical tests show that the first oxidation for these porphyrins occurs at a potential greater than that of the I(-)/I(3)(-) redox couple, and attachment of EDGs to the periphery of the porphyrin facilitates electron abstraction. The photovoltaic measurements show that YD14 and YD17 have a power conversion efficiency of similar to 7%. Introduction of EDGs to various meso-positions is demonstrated to be achievable, and porphyrin dyes with appropriate EDGs are promising candidates for highly efficient DSSCs

Porphyrin Dyes with High Injection and Low Recombination for Highly Efficient Mesoscopic Dye-Sensitized Solar Cells

The photovoltaic performance and charge recombination characteristics of porphyrin-based dye-sensitized solar cell (DSC) devices have been investigated using the impedance spectroscopy (IS) technique. The IS results provide key information related to the device performance for a highly efficient porphyrin dye (YD2), a reference porphyrin dye (YD0), and a commercial ruthenium dye (N719). The DSC devices constructed using YD2 and N719 dyes reach similar internal power conversion efficiencies (7.41% vs 7.54%) due to the higher injection of the YD2 dye that is compromised by a lower photovoltage. In addition, both YD2 and N719 dyes exhibit the same charge-transfer resistance, indicating that the recombination rates of both dyes are very similar. The diarylamino group plays a key role to repel the triiodide ions from the titania surface so that the charge recombination of YD2 is less significant compared with that of YD0