Probing slow dynamics by ultrafast process: Sol–gel transition detected by transient absorption spectroscopy of quantum dots

Piątkowski, P.; Ratajska-Gadomska, B.; Gadomski, W.

doi:10.1016/j.molliq.2012.06.027

Cited by 2 publications

(5 citation statements)

References 30 publications

(98 reference statements)

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“…The femtosecond transient absorption (TA) setup used in this research has been described elsewhere . First, the output of Coherent sapphire oscillator Micra 10 is amplified using Coherent Legend Elite.…”

Section: Methodsmentioning

confidence: 99%

“…The femtosecond transient absorption (TA) setup used in this research has been described elsewhere. 52 First, the output of Coherent sapphire oscillator Micra 10 is amplified using Coherent Legend Elite. The output pulse (3.5 mJ and 45 fs time duration at 800 nm) is then divided into two pulses.…”

Section: Methodsmentioning

confidence: 99%

“…Another important component of DSSCs is the photosensitizer (dye), and its optimization has been addressed in several papers. − Traditional dyes with a metal center can be replaced by the metal-free organic ones, namely, D205, D149, D102, D131, and so forth, with the common substituted indoline donor moiety D . These are more environment-friendly and less expensive compared to the dyes with metal centers .…”

Section: Introductionmentioning

confidence: 99%

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Effect of the Mixture Composition of BmimBF₄–Acetonitrile on the Excited-State Relaxation Dynamics of a Solar-Cell Dye D149: An Ultrafast Transient Absorption Study

et al. 2021

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The excited-state relaxation dynamics of D149, one of the metal-free substituted indoline dyes used in dye-sensitized solar cells, is studied in the whole composition range of the 1butyl-3-methylimidazolium tetrafluoroborate (BmimBF 4 )−acetonitrile binary mixture by using time-integrated absorption, emission, and time-resolved transient absorption (TA) spectroscopies. The comparative analysis of absorption and emission spectra indicates that the value of Stokes shift reduces monotonically with decreasing mixture polarity. The global analysis of timeresolved TA spectra indicates the presence of four different time components related to different processes in the excited state of the dye. Importantly, the observed timescales are highly sensitive to composition, polarity, and viscosity of the binary mixture. Increase of viscosity and decrease of polarity observed for increasing ionic liquid (IL) content in the mixture lead to overall increase in the emission lifetime (S 1 −S 0 ) of D149. At a lower IL mole fraction (X IL = 0.1), the emission lifetime shows a minimum that can be traced back to the change from the situation in which the local environment of the dye is dominated by the interactions in acetonitrile to that in which it is dominated by those in BmimBF 4 . This also is reflected in the occurrence of a minimum in relative quantum yield in the same range of X IL . The origin of the other moderately long-time component (33 ps in ACN-120 ps in BmimBF 4 ) is still debatable; however, for pure IL and all the mixtures, the composition dependence of this timescale is similar to that of the longest emission lifetime.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of the Mixture Composition of BmimBF₄–Acetonitrile on the Excited-State Relaxation Dynamics of a Solar-Cell Dye D149: An Ultrafast Transient Absorption Study

et al. 2021

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“…Femtosecond transient absorption setup used in this research has been described elsewhere. 52 First, the output of Coherent sapphire oscillator Micra 10 is amplified using Coherent Legend Elite. The output pulse (3.5 mJ and 45 fs time duration at 800 nm) is then divided into two pulses.…”

Section: Femtosecond Transient Absorption (Ta) Spectroscopymentioning

confidence: 99%

“…18,19 Another important component of DSSC is the photosensitizer (dye) and its optimization has been addressed in several papers. [20][21][22][23][24][25][26] Traditional dyes with metal center can be replaced by the metal free organic ones, namely D205, D149, D102, D131 etc., with common substituted indoline donor moiety D. 27 These are more environment friendly and less expensive compared to the dyes with metal centers. 25 These type of organic dyes were designed to have a donoranchor group-acceptor (D-π-A) structure.…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Mixture Composition of BmimBF4-Acetonitrile on the Excited State Relaxation Dynamics of a Solar Cell Dye D149: An Ultrafast Transient Absorption Study

Maity

Piątkowski²,

Polok³

et al. 2021

Preprint

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It has been recognized that the understanding of the photo physic of the dyes used in solar cells in an important step in improving their efficiency. Certainly using ionic liquid as an electrolyte is a good solution as it stabilizes the excited state of the dye, however, because of the high viscosity, the diffusion of the components of the solar cell (dye, electrolyte, the chosen redox couple) is very low and has consequences on the other processes (Forward and backward processes). One of the ideas, is to modulate the viscosity of the ionic liquid by mixing the ionic liquid with a solvent. The goal then of this work is to quantify the mixture composition dependence of the excited state relaxation times. Other studies should be carried out to quantify the mixture dependence on the time characteristics of other processes (charge injection, collection etc.) to optimize the working optimal conditions of the solar cell. Following this goal, the present study is devoted to characterize the relaxation time of in the whole mixture composition of BmimBF4 and acetonitrile and in the neat components. For the first time, the decay relaxation times of the first excited electronic state of D149 dye, as obtained by transient absorption spectroscopy (TAS). These relaxation times are monitored by a gradual change of the local structure around a dye, from the one dominated by the interionic interactions, high viscosity and low polarity (as quantified by the static dielectric constant) in BmimBF4 to the one that is dominated by dipole-dipole interactions, low viscosity and high polarity in acetonitrile.<br>

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Probing slow dynamics by ultrafast process: Sol–gel transition detected by transient absorption spectroscopy of quantum dots

Cited by 2 publications

References 30 publications

Effect of the Mixture Composition of BmimBF₄–Acetonitrile on the Excited-State Relaxation Dynamics of a Solar-Cell Dye D149: An Ultrafast Transient Absorption Study

Effect of the Mixture Composition of BmimBF₄–Acetonitrile on the Excited-State Relaxation Dynamics of a Solar-Cell Dye D149: An Ultrafast Transient Absorption Study

The Effect of the Mixture Composition of BmimBF4-Acetonitrile on the Excited State Relaxation Dynamics of a Solar Cell Dye D149: An Ultrafast Transient Absorption Study

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Probing slow dynamics by ultrafast process: Sol–gel transition detected by transient absorption spectroscopy of quantum dots

Cited by 2 publications

References 30 publications

Effect of the Mixture Composition of BmimBF4–Acetonitrile on the Excited-State Relaxation Dynamics of a Solar-Cell Dye D149: An Ultrafast Transient Absorption Study

Effect of the Mixture Composition of BmimBF4–Acetonitrile on the Excited-State Relaxation Dynamics of a Solar-Cell Dye D149: An Ultrafast Transient Absorption Study

The Effect of the Mixture Composition of BmimBF4-Acetonitrile on the Excited State Relaxation Dynamics of a Solar Cell Dye D149: An Ultrafast Transient Absorption Study

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Effect of the Mixture Composition of BmimBF₄–Acetonitrile on the Excited-State Relaxation Dynamics of a Solar-Cell Dye D149: An Ultrafast Transient Absorption Study

Effect of the Mixture Composition of BmimBF₄–Acetonitrile on the Excited-State Relaxation Dynamics of a Solar-Cell Dye D149: An Ultrafast Transient Absorption Study