Effect of dye concentration on electron injection efficiency in nanocrystalline TiO2 films sensitized with N719 dye

Katoh, Ryuzi; Yaguchi, Kaori; Furube, Akihiro

doi:10.1016/j.cplett.2011.06.046

Cited by 29 publications

(22 citation statements)

References 16 publications

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“…We applied this technique to the study of Z907 dye-sensitized TiO 2 films, which are from the same family of N719 and N3 Ru-based dyes. According to earlier transient absorption studies on N719 (cis-bis (isothiocyanate)bis(4,4′-dicarboxylic-2,2′-bipyridyl) ruthenium(II)) and N3 (cis-di(thiocyanate)bis(2,2′-bipyridyl-4,4′-dicarboxylic acid)ruthenium(II)) dye-sensitized TiO 2 films, the transient absorption spectrum around 800 nm is assigned to the oxidized dye molecules 13 23 24 25 and the absorption spectrum around 1200 nm is attributed to absorption by conduction band electrons 13 26 27 . The kinetics of electron injection in the complete device is studied by monitoring the evolution of oxidized dye molecules and photo-injected electrons in TiO 2 .…”

Section: Resultsmentioning

confidence: 96%

Ultrafast charge separation dynamics in opaque, operational dye-sensitized solar cells revealed by femtosecond diffuse reflectance spectroscopy

Ghadiri

Zakeeruddin

Hagfeldt

et al. 2016

Sci Rep

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Efficient dye-sensitized solar cells are based on highly diffusive mesoscopic layers that render these devices opaque and unsuitable for ultrafast transient absorption spectroscopy measurements in transmission mode. We developed a novel sub-200 femtosecond time-resolved diffuse reflectance spectroscopy scheme combined with potentiostatic control to study various solar cells in fully operational condition. We studied performance optimized devices based on liquid redox electrolytes and opaque TiO2 films, as well as other morphologies, such as TiO2 fibers and nanotubes. Charge injection from the Z907 dye in all TiO2 morphologies was observed to take place in the sub-200 fs time scale. The kinetics of electron-hole back recombination has features in the picosecond to nanosecond time scale. This observation is significantly different from what was reported in the literature where the electron-hole back recombination for transparent films of small particles is generally accepted to occur on a longer time scale of microseconds. The kinetics of the ultrafast electron injection remained unchanged for voltages between +500 mV and –690 mV, where the injection yield eventually drops steeply. The primary charge separation in Y123 organic dye based devices was clearly slower occurring in two picoseconds and no kinetic component on the shorter femtosecond time scale was recorded.

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Section: Resultsmentioning

confidence: 96%

Ultrafast charge separation dynamics in opaque, operational dye-sensitized solar cells revealed by femtosecond diffuse reflectance spectroscopy

Ghadiri

Zakeeruddin

Hagfeldt

et al. 2016

Sci Rep

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“…Actually, the thickness of the dye layer can be estimated from the number of dye molecules adsorbed onto the surface if the volume occupied by a single dye molecule,V dye , isknown. We assumed V dye to be V dye = 1 nm 3 based on the area occupied by a single N719 dye molecule on the TiO 2 surface obtained from the adsorption isotherm [18] and the atomic force microscopy image of N719 on TiO 2 single crystals [19]. The same V dye value was used for the other dyes because the number of adsorbed D149 and MK2 dye molecules was similar to the number of adsorbed N719 molecules, as mentioned above.…”

Section: Resultsmentioning

confidence: 99%

Exciton annihilation in dye-sensitized nanocrystalline semiconductor films

Namekawa

Katoh

2016

Chemical Physics Letters

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Exciton annihilation in dye-sensitizednanocrystalline semiconductor (Al 2 O 3) films has been studied through laser-induced fluorescence spectroscopy. The relative quantum yield of the fluorescence decreases with increasing excitation light intensity, the indication being that exciton annihilation occurred. The rate constants of the annihilation were estimated for three dyes, N719, D149, and MK2, that are known to be sensitizing dyes for efficient dye-sensitized solar cells. The hopping time between dye molecules and the diffusion length of excitons within their lifetime were also estimated to facilitate discussion of the relevance of exciton annihilation to primary processes in dye-sensitized solar cells.

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“…1 Therefore, one-dimensional nanostructures offer the best morphology. Since N719 dye molecules are not likely to aggregate, it could be assumed that the dye should be adsorbed as monolayer; 29,30 therefore, increasing the surface area causes an increase in the amount of adsorbed dye and as a result, enhances the efficiency of the solar cell. 31 The amount of adsorbed dye is expected to be greater for nanotubes and nanowires compared to template-free synthesized TiO 2 .…”

Section: Resultsmentioning

confidence: 99%

Amyloid-like peptide nanofiber templated titania nanostructures as dye sensitized solar cell anodic materials

et al. 2013

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One-dimensional titania nanostructures can serve as a support for light absorbing molecules and result in an improvement in the short circuit current (Jsc) and open circuit voltage (Voc) as a nanostructured and high-surface-area material in dye-sensitized solar cells. Here, self-assembled amyloid-like peptide nanofibers were exploited as an organic template for the growth of one-dimensional titania nanostructures. Nanostructured titania layers were utilized as anodic materials in dye sensitized solar cells (DSSCs). The photovoltaic performance of the DSSC devices was assessed and an enhancement in the overall cell performance compared to unstructured titania was observed. © 2013 The Royal Society of Chemistry

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Effect of dye concentration on electron injection efficiency in nanocrystalline TiO2 films sensitized with N719 dye

Cited by 29 publications

References 16 publications

Ultrafast charge separation dynamics in opaque, operational dye-sensitized solar cells revealed by femtosecond diffuse reflectance spectroscopy

Ultrafast charge separation dynamics in opaque, operational dye-sensitized solar cells revealed by femtosecond diffuse reflectance spectroscopy

Exciton annihilation in dye-sensitized nanocrystalline semiconductor films

Amyloid-like peptide nanofiber templated titania nanostructures as dye sensitized solar cell anodic materials

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