Transport and interfacial transfer of electrons in dye-sensitized nanocrystalline solar cells

Peter, Laurence M.; Duffy, Noel W.; Wang, R.L; Wijayantha, K. G. Upul

doi:10.1016/s0022-0728(02)00689-7

Cited by 135 publications

(99 citation statements)

References 42 publications

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“…φ(FTO) ) 4.7 eV and φ(I -/I 3 -) ) 4.85 eV (vs electron at rest in a vacuum), which imply U 0 ≈ 0.15 V when the two systems reach equilibrium in the dark, as confirmed by electrochemistry measurements. 15 A part of this difference could be due to the modification of the redox potential of the electrolyte (I -/I 2 redox couple) due to the organic solvent used in the DSSC. It must be also emphasized that the results shown in Figure 7 were not obtained under equilibrium but under DSSC working conditions (150 W Xe lamp illumination and variable potential bias).…”

Section: Discussionmentioning

confidence: 99%

Flatband Potential of F:SnO₂ in a TiO₂ Dye-Sensitized Solar Cell: An Interference Reflection Study

2003

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A model for the analysis of interference reflection data of nanoporous TiO 2 dye-sensitized solar cells (DSSC) is presented. It is shown that the interference reflection technique [Turrión, M.;Macht, B.;Tributsch, H.; Salvador, P. J. Phys. Chem. B 2001, 105, 9732] allows one to monitor very precisely the evolution of the depletion layer of the fluor-doped SnO 2 (FTO) conducting substrate at the DSSC back contact with the position of the Fermi level. The model shows that this technique features a much larger sensitivity than the capacitancevoltage Mott-Schottky method for determining both the flatband potential (U 0 ) and the Helmholtz layer capacitance (C H ) at the FTO/electrolyte interface, under working conditions of the DSSC. Under illumination the band-bending in the FTO substrate is controlled by two factors: (a) the position of Fermi level (FTO bulk potential), which is determined by the accumulation of photogenerated electrons in the conduction band of the nanostructured TiO 2 film, and (b) the values of U 0 and C H , which determine the potential distribution at the FTO/electrolyte interface. It is suggested that both parameters U 0 and C H determine a constraint on the maximum photovoltage attainable by the DSSC, as the conduction band edge of the FTO at the FTO/TiO 2 interface cannot be higher than that of the TiO 2 , otherwise the transfer of dye photoinjected electrons from the TiO 2 to the FTO would be hindered. According to our analysis, it can be concluded that the theoretical maximum photovoltage cannot be higher than 0.8 V, a value never surpassed experimentally with untreated DSSC.

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Section: Discussionmentioning

confidence: 99%

Flatband Potential of F:SnO₂ in a TiO₂ Dye-Sensitized Solar Cell: An Interference Reflection Study

2003

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“…This method has been applied in many works for investigation of DOS in conducting polymers, 54,91 quantum dots, 59 and porous semiconductors. 13,82,[92][93][94] The electrochemical determination of the (10), is exponential…”

Section: Factors Affecting the Chemical Capacitancementioning

confidence: 99%

“…92,95,96 In organic conductors, disorder or structural correlations with correlation lengths of a few intermolecular distances (fluctuation in the local conjugation length) lead to a dispersion of energies. It is widely agreed that the distribution of electronic states in disordered organic conductors has a Gaussian shape, and this is observed by capacitance measurements.…”

Section: Factors Affecting the Chemical Capacitancementioning

confidence: 99%

Physical electrochemistry of nanostructured devices

Bisquert

2008

Phys. Chem. Chem. Phys.

243

273

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“…The increased electron lifetime using the dimer may originate from slower electron transport within the TiO 2 in a trap-controlled recombination mechanism. [30] Figure 3(c) shows that there are only minimal differences observed in the diffusion coefficients of DSSCs constructed from each dye system when plotted as a function of J sc . This result indicates that variation in the charge transport is not the main origin of the increased lifetime for the dimer DSSCs.…”

Section: Electron Lifetime In Dsscsmentioning

confidence: 99%

A Nonconjugated Bridge in Dimer-Sensitized Solar Cells Retards Charge Recombination without Decreasing Charge Injection Efficiency

Sunahara

Griffith

Uchiyama

et al. 2013

ACS Appl. Mater. Interfaces

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A nonconjugated bridge in dimer-sensitized solar cells retards charge recombination without decreasing charge injection efficiency AbstractDye sensitized solar cells (DSSCs) employing a dimer porphyrin, which was synthesised with two porphyrin units connected without conjugation, have shown that both porphyrin components can contribute to photocurrent generation, that is, more than 50 % internal quantum efficiency. In addition, the open-circuit voltage (Voc) of the DSSCs was higher than that of DSSCs using monomer porphyrins. In this paper, we first optimized cell structure and fabrication conditions. We obtained more than 80% incident photon to current conversion efficiency from the dimer porphyrin sensitized DSSCs and higher Voc and energy conversion efficiency than monomer porphyrin sensitized solar cells. To examine the origin of the higher Voc, we measured electron lifetime in the DSSCs with various conditions, and found that the dimer system increased the electron lifetime by improving the steric blocking effect of the dye layer, whilst the lack of a conjugated linker prevents an increase in the attractive force between conjugated sensitizers and the acceptor species in the electrolyte. The results support a hypothesis; dispersion force is one of the factors influencing the electron lifetime in DSSCs. ABSTRACTDye sensitised solar cells (DSSCs) employing a dimer porphyrin, which was synthesised with two porphyrin units connected without conjugation, have shown that both porphyrin components can contribute to photocurrent generation, that is, more than 50 % incident photon to current conversion (IPCE) efficiency. In addition, the open-circuit voltage (V oc ) of the DSSCs was higher than that of DSSCs using monomer porphyrins. In this paper, we first optimized cell structure and fabrication conditions and obtained more than 80 % IPCE from the dimer porphyrin sensitized DSSCs and higher V oc and energy conversion efficiency than monomer porphyrin sensitized solar cells. In order to examine the origin of the higher V oc , we measured electron lifetime in the DSSCs with various conditions, and found that the dimer system increased the electron lifetime by improving the steric blocking effect of the dye layer, whilst the lack of a conjugated linker prevents an increase in the attractive force between conjugated sensitisers and the acceptor species in the electrolyte. The results support a hypothesis; dispersion forces are one of the factors influencing the electron lifetime in DSSCs.

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Transport and interfacial transfer of electrons in dye-sensitized nanocrystalline solar cells

Cited by 135 publications

References 42 publications

Flatband Potential of F:SnO₂ in a TiO₂ Dye-Sensitized Solar Cell: An Interference Reflection Study

Flatband Potential of F:SnO₂ in a TiO₂ Dye-Sensitized Solar Cell: An Interference Reflection Study

Physical electrochemistry of nanostructured devices

A Nonconjugated Bridge in Dimer-Sensitized Solar Cells Retards Charge Recombination without Decreasing Charge Injection Efficiency

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Transport and interfacial transfer of electrons in dye-sensitized nanocrystalline solar cells

Cited by 135 publications

References 42 publications

Flatband Potential of F:SnO2 in a TiO2 Dye-Sensitized Solar Cell: An Interference Reflection Study

Flatband Potential of F:SnO2 in a TiO2 Dye-Sensitized Solar Cell: An Interference Reflection Study

Physical electrochemistry of nanostructured devices

A Nonconjugated Bridge in Dimer-Sensitized Solar Cells Retards Charge Recombination without Decreasing Charge Injection Efficiency

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Flatband Potential of F:SnO₂ in a TiO₂ Dye-Sensitized Solar Cell: An Interference Reflection Study

Flatband Potential of F:SnO₂ in a TiO₂ Dye-Sensitized Solar Cell: An Interference Reflection Study