Electron Kinetics in Dye Sensitized Solar Cells Employing Anatase with (101) and (001) Facets

Laskova, Barbora; Moehl, Thomas; Kavan, Ladislav; Zukalová, Markéta; Liu, Xianjie; Yella, Aswani; Comte, Pascal; Zukal, Arnošt; Nazeeruddin, Mohammad Khaja; Gräetzel, Michael

doi:10.1016/j.electacta.2015.02.016

Cited by 12 publications

(7 citation statements)

References 78 publications

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“…In order to quantitatively analyze the percentage of {001} facets, Raman spectroscopy was carried out as shown in Fig. 1(b) 24 27 . The peaks at 144, 394, 514, and 636 cm −1 suggest the typical anatase TiO 2 phase, being consistent with the XRD results.…”

Section: Resultsmentioning

confidence: 99%

“…To date, there have been a large number of reports for preparing anatase TiO 2 single crystal with appropriately exposed {001} facets for application of enhanced DSSCs, such as TiO 2 nanotube 20 , anatase TiO 2 nanosheets 21 , yolk@shell anatase TiO 2 hierarchical microspheres 22 , and mesoporous TiO 2 single crystals 9 . Yet it was reported that the ratio of {001} and {101} facet has impact on the performance of nanodevice because of the “surface heterojunction” of {001} and {101} surfaces, where appropriate but not great proportion of {001} facets is beneficial to the transfer and separation of photogenerated electrons and holes 23 24 .…”

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confidence: 99%

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Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells

Chu

Qin

Yang

et al. 2015

Sci Rep

115

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Anatase TiO2 nanoparticles with exposed {001} facets were synthesized from Ti powder via a sequential hydrothermal reaction process. At the first-step hydrothermal reaction, H-titanate nanowires were obtained in NaOH solution with Ti powder, and at second-step hydrothermal reaction, anatase TiO2 nanoparticles with exposed {001} facets were formed in NH4F solution. If the second-step hydrothermal reaction was carried out in pure water, the H-titanate nanowires were decomposed into random shape anatase-TiO2 nanostructures, as well as few impurity of H2Ti8O17 phase and rutile TiO2 phase. Then, the as-prepared TiO2 nanostructures synthesized in NH4F solution and pure water were applied to the photoanodes of dye-sensitized solar cells (DSSCs), which exhibited power conversion efficiency (PCE) of 7.06% (VOC of 0.756 V, JSC of 14.80 mA/cm2, FF of 0.631) and 3.47% (VOC of 0.764 V, JSC of 6.86 mA/cm2, FF of 0.662), respectively. The outstanding performance of DSSCs based on anatase TiO2 nanoparticles with exposed {001} facets was attributed to the high activity and large special surface area for excellent capacity of dye adsorption.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells

Chu

Qin

Yang

et al. 2015

Sci Rep

115

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“…By contrast, the 20 nm photoanode renders a higher density of states. [ 24 ] Remarkably, the crystallinity of the 30 nm NPs increases with the NP size, which is affi rmed by the profound diffraction peaks relative to those of the 20 nm NPs in the XRD pattern. However, lacking in exposed {001} facets, the 30 nm TiO 2 photoanode is marred by low R ct and C µ because its spacious mesoporous structure enables the bulky cobalt mediator to access several TiO 2 recombination centers.…”

Section: Electrochemical Characterization and Dsc Performancementioning

confidence: 96%

Trifunctional TiO₂ Nanoparticles with Exposed {001} Facets as Additives in Cobalt‐Based Porphyrin‐Sensitized Solar Cells

Zhai

Hsieh

Yeh

et al. 2015

Adv Funct Materials

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In this study, highly mesoporous TiO2 composite photoanodes composed of functional {001}‐faceted TiO2 nanoparticles (NPs) and commercially available 20 nm TiO2 NPs are employed in efficient porphyrin‐sensitized solar cells together with cobalt polypyridyl‐based mediators. Large TiO2 NPs (approximately 50 nm) with exposed {001} facets are prepared using a fast microwave‐assisted hydrothermal (FMAH) method. These unique composite photoanodes favorably mitigate the aggregation of porphyrin on the surface of TiO2 NPs and strongly facilitate the mass transport of cobalt‐polypyridyl‐based electrolytes in the mesoporous structure. Linear sweep voltammetry reveals that the transportation of Co(polypyridyl) redox is a diffusion‐controlled process, which is highly dependent on the porosity of TiO2 films. Electrochemical impedance spectroscopy confirms that the FMAH TiO2 NPs effectively suppress the interfacial charge recombination toward [Co(bpy)3]3+ because of their oxidative {001} facets. In an optimal condition of 40 wt% addition of FMAH TiO2 NPs in the final formula, the power conversion efficiency of the dye‐sensitized cells improves from 8.28% to 9.53% under AM1.5 (1 sun) conditions.

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“…The first strategy is mostly based on electrolyte additives such as 4-tert-butylpyridine (TBP) which causes not only the desired Fermi level shift, but also increases the resistance to electron recombination [4][5][6]. (The same effect, albeit less pronounced, is achievable through the crystal-face engineering in titania photoanode [7,8]). The second strategy is more versatile in view of a large palette of redox couples to be selected to this purpose.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Properties of Cu(II/I)-Based Redox Mediators for Dye-Sensitized Solar Cells

Kavan

Saygılı

Freitag

et al. 2017

Electrochimica Acta

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100

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Three Cu(II/I)-phenanthroline and Cu(II/I)-bipyridine redox mediators are studied on various electrodes and in variety of electrolyte solutions using cyclic voltammetry and impedance spectroscopy on symmetrical dummy cells. Graphene-based catalysts provide comparably high activity to PEDOT, and both catalysts outperform the activity of platinum. The chargetransfer kinetics and the diffusion rate significantly slowdown in the presence 4-tertbutylpyridine. This effect is specific only for Cu-mediators (is missing for Co-mediators), and is ascribed to a sensitivity of the coordination sphere of the Cu(II)-species to structural and substitutional changes. The 'Zombie Cells' made from symmetrical PEDOT/PEDOT devices exhibit enhanced charge-transfer rate and enhanced diffusion resistance. Electrochemically clean Cu(II)-bipyridine species are prepared, for the first time, by electrochemical oxidation of the parent Cu(I) complexes. Our preparative electrolysis brings numerous advantages over the standard chemical syntheses of the Cu(II)-bipyridine complexes. The superior performance of electrochemically-grown clean Cu(II)-bipyridine complex is demonstrated on practical dye-sensitized solar cells.

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Electron Kinetics in Dye Sensitized Solar Cells Employing Anatase with (101) and (001) Facets

Cited by 12 publications

References 78 publications

Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells

Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells

Trifunctional TiO₂ Nanoparticles with Exposed {001} Facets as Additives in Cobalt‐Based Porphyrin‐Sensitized Solar Cells

Electrochemical Properties of Cu(II/I)-Based Redox Mediators for Dye-Sensitized Solar Cells

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Electron Kinetics in Dye Sensitized Solar Cells Employing Anatase with (101) and (001) Facets

Cited by 12 publications

References 78 publications

Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells

Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells

Trifunctional TiO2 Nanoparticles with Exposed {001} Facets as Additives in Cobalt‐Based Porphyrin‐Sensitized Solar Cells

Electrochemical Properties of Cu(II/I)-Based Redox Mediators for Dye-Sensitized Solar Cells

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Trifunctional TiO₂ Nanoparticles with Exposed {001} Facets as Additives in Cobalt‐Based Porphyrin‐Sensitized Solar Cells