In-situ analyses of triiodide formation in an iodine-free electrolyte for dye-sensitized solar cells using electro-diffuse-reflection spectroscopy (EDRS)

Seo, Seok-Jun; Bialecka, K.; Kang, Moon‐Sung; Hinsch, Andreas; Moon, Seung‐Hyeon

doi:10.1016/j.jpowsour.2014.11.070

Cited by 4 publications

(4 citation statements)

References 35 publications

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“…

I_{lim}

can be measured by either exposing the cell to high‐intensity illumination, or from the reverse bias region in an I–V curve measured in the dark. [ 32,33 ] These measurements should be used with care, since exposure to high intensities may heat the cells and high reverse bias can affect cell performance. Using values measured by Mastroianni et al [ 32 ] for a DSC with a

I_{3}^{-} / I^{-}

redox couple, the diffusion coefficient

D_{I_{3}^{-}}

was between

6.8 \times 10^{- 6}

and

7.5 \times 10^{- 6}

cm 2 s −1 (for

c_{I_{3}^{-}} = 0.050

and

0.025

mol dm −3 , respectively) at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Predictive Modeling of Dye Solar Cell Degradation

Poskela¹,

Tiihonen

Palonen³

et al. 2022

Solar RRL

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Degradation of dye solar cell performance based on the early changes in electrolyte color is predicted, allowing to estimate the lifetime of the dye solar cells even before their efficiency declines. Previous predictive models commonly rely on regression analysis of the predicted parameter; thus, they are unable to capture degradation before a significant decrease in performance. Degradation tests, even when accelerated, may take thousands of hours. As such, recognizing degradation trends early can lead to rewarding cuts in the duration of solar cell development pipelines. With accurate lifetime predictions, researchers can steer materials research to reach longer lifetimes in shorter cycles. The predictive power of our model relies on color changes in the electrolyte that directly correlate with the concentration of tri‐iodide charge carriers within it, the loss of which is the predominant degradation mechanism for most liquid‐electrolyte dye solar cells. By linking the physical mechanisms inside the cell, which eventually start to degrade the performance of dye solar cells, an early prediction of the lifetime can be made even when the device performance still appears stable. It is exemplified with dye solar cells that integrating architecture‐specific knowledge on degradation mechanisms has potential to improve lifetime predictions for photovoltaics.

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“…

I_{lim}

I_{3}^{-} / I^{-}

redox couple, the diffusion coefficient

D_{I_{3}^{-}}

was between

6.8 \times 10^{- 6}

and

7.5 \times 10^{- 6}

cm 2 s −1 (for

c_{I_{3}^{-}} = 0.050

and

0.025

mol dm −3 , respectively) at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Predictive Modeling of Dye Solar Cell Degradation

Poskela¹,

Tiihonen

Palonen³

et al. 2022

Solar RRL

View full text Add to dashboard Cite

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“…As expected, the large increase in Iconcentration, using the MPII/I2 electrolyte (D2I) generated much higher Voc and Jsc than its MPITFSI/I2 counterpart. Interestingly, the omission of I2 from MPII drastically improved Jsc and Voc probably due to the difference between Fermi level of TiO2 and redox potential of electrolyte [52] but led to a reduced FF due to a higher charge transport resistance associated with the insufficient amount of I3 - [56,73]. It has been demonstrated that the imidazolium-based IL could be used as the sole charge transfer mediate [80].…”

Section: Photovoltaic Performance Of Ionic Liquid-based Electrolytesmentioning

confidence: 99%

“…We assumed that the in-situ generation of I3ions in I2-free DSSCs was sufficient for the DSSC operation. In 2005, Seo et al [73] presented the first electro-diffuse-reflection spectroscopy study on the I3in-situ generation of I2-free DSSCs during working conditions. Prehal et al [74] used in-situ Raman spectroscopy to successfully demonstrate the reversible formation of I3 -, I5 -, and I2 in the carbon nanopores produced by the oxidation of I -.…”

Section: Introductionmentioning

confidence: 99%

Remarkable 8.3% efficiency and extended electron lifetime towards highly stable semi-transparent iodine-free DSSCs by mitigating the in-situ triiodide generation

Bharwal

Manceriu

Olivier

et al. 2022

Chemical Engineering Journal

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“…Appearances of various redox species in the electrolytes of the DSCs have been studied both experimentally and by quantum chemical methods. − We used the symmetric I 3 – stretching band to monitor conversion of iodide of the electrolyte solution into I 3 – on the photoelectrode under Raman illumination and its concentration dependence on electrolyte additives. Addition of GuSCN, in particular, seemed to reduce triiodide concentrations in the electrolyte solutions.…”

Section: Introductionmentioning

confidence: 99%

Intriguing Photochemistry of the Additives in the Dye-Sensitized Solar Cells

et al. 2016

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Over the years numerous mixes of chemical compounds have been tried in the electrolytes of dye-sensitized solar cells in efforts to improve their efficiency. How these chemicals interact with each other and the photoelectrode has received surprisingly little attention. Here we report results from a systematic study of two I-/I3electrolytes and their additives using infrared and Raman spectroscopy together with quantum chemical calculations. In the LiI electrolyte competing interactions between lithium cation and the solvent MPN and the additives TBP, NMBI and GuSCN were identified. These interactions could inhibit the interaction of lithium ions with the TiO2 surface. It was found that under Raman excitation of PMII solution in contact with the photoelectrode, efficient generation of I3takes place. For LiI solution, in addition, a Dye-I2 complex is formed. The results could be explained by diffusion limited build-up of I3and depletion of Iconcentrations in the focal area of the excitation beam and by reduction of I3via conduction band electrons of TiO2 beyond the focal region. To explain the formation of Dye-I2 complexes in the LiI electrolyte solutions a multi-step regeneration mechanism is proposed. It was found that GuSCN reduces the I3concentration in the electrolyte solutions studied, in the LiI electrolyte in addition it binds to lithium ions and nearly depletes the Dye-I2 complexes. From infrared spectra, it became clear that preventing water entering the DSCs during the preparation stages in ambient air is a demanding task. The identified interactions paint an intriguing new photochemical landscape of the function of the dye-sensitized solar cells giving guidelines for further development of the devices.

show abstract

In-situ analyses of triiodide formation in an iodine-free electrolyte for dye-sensitized solar cells using electro-diffuse-reflection spectroscopy (EDRS)

Cited by 4 publications

References 35 publications

Predictive Modeling of Dye Solar Cell Degradation

Predictive Modeling of Dye Solar Cell Degradation

Remarkable 8.3% efficiency and extended electron lifetime towards highly stable semi-transparent iodine-free DSSCs by mitigating the in-situ triiodide generation

Intriguing Photochemistry of the Additives in the Dye-Sensitized Solar Cells

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