Probing the Relative Photoinjection Yields of Monomer and Aggregated Dyes into ZnO Crystals

King, Laurie A.; Parkinson, B. A.

doi:10.1021/acs.langmuir.6b03395

Cited by 3 publications

(2 citation statements)

References 42 publications

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“…Yet, Liu et al did not observe the line-distributed features of N3 nanoaggregates across the TiO 2 surface. Meanwhile, Takeda and Parkinson observed such nanoaggregates by AFM on different dye···semiconductor interfaces: squaraine dyes on SnS 2 , and cyanine dyes on TiO 2 and on ZnO. , To this end, the work of Parkinson at al . is in common with our study; although they used anatase TiO 2 .…”

Section: Results and Discussionmentioning

confidence: 99%

Imaging Dye Aggregation in MK-2, N3, N749, and SQ-2 dye···TiO₂ Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes

Chen

Cole

Stenning

et al. 2020

ACS Appl. Energy Mater.

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Dye-sensitized solar cells (DSSCs) are a strong contender for next-generation photovoltaic technology with niche applications as solar-powered windows. The performance of a DSSC is particularly susceptible to the dye sensitizer, which is adsorbed onto the surface of a wide-band-gap semiconductor such as TiO 2 , to form the working electrode. The nature by which such surfaces are sensitized stands to influence the resulting dye•••TiO 2 interfacial structure and thence the operational performance of the DSSC working electrode. In particular, a nanoscopic understanding of the sensitization process would ultimately help to improve DSSC device function. In this study, atomic force microscopy (AFM) is used to image the nanoscopic formation of dye•••TiO 2 interfacial structures. This employs, as case studies, four well-known DSSC dyes adsorbed onto amorphous TiO 2 substrates: two ruthenium-based dyes, N3 and the Black Dye (N749); and two organic dyes, the thiophenylcarbazole, MK-2, and the zwitterionic squaraine, SQ-2. We discover that all four dyes present some form of aggregation upon sensitization of TiO 2 , whose spatial distributions show distinct nanoaggregate particle characteristics. These particle clusters of N749, N3, and MK-2 are found to assemble in lines of nanoaggregates, while clusters of SQ-2 dye chromophores distribute themselves randomly on the amorphous TiO 2 substrates. This nanoparticle structural assembly persists even when these dye•••TiO 2 interfaces are fabricated using hundred-fold diluted dye sensitization concentrations. The formation of dye aggregates in N749 is further studied as a function of dye sensitization time. This tracks the pattern formation of aggregates of N749 and reveals that dye aggregation begins within the first hour and has completed within a 5 h period. The large expanse of dye nanoaggregates observed shows that dye•••dye interactions are much more important than previously envisaged, while the nature of their spatial distribution can be related to different aggregation modes of the dye molecules. These nanostructural features will undoubtedly impact the performance of DSSCs.

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Section: Results and Discussionmentioning

confidence: 99%

Imaging Dye Aggregation in MK-2, N3, N749, and SQ-2 dye···TiO₂ Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes

Chen

Cole

Stenning

et al. 2020

ACS Appl. Energy Mater.

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“…The fluorescence levels of dyes in Figure were normalized for clarity. The nonemissive character of their excited state has, in the same fashion, become commonly accepted as a general feature of H-aggregates when stacked onto a surface of substrates, − and their interaction with light is sharply modified. All OH-substituted dyes exhibited aggregation features at the TiO 2 surface to the red and blue region of the spectrum, with a maximum of adsorption ranging from 600 to 700 nm (Figure ).…”

Section: Results and Discussionmentioning

confidence: 96%

Deep Blue Asymmetrical Streptocyanine Dyes: Synthesis, Spectroscopic Characterizations, and Ion-Specific Cooperative Adsorption at the Surface of TiO₂ Anatase Nanoparticles

et al. 2017

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Various triflate (TfO–), tetrafluoroborate (BF4 –), and perchlorate (ClO4 –) salts of (E)-9-(3-(4-(diphenylamino)phenyl)allylidene)-9H-carbazol-9-ium chromophores, asymmetrical streptocyanine blue dyes, were synthesized, and their structures and photochemical and electrochemical properties were characterized. Displaying a high absorption band in the wavelength range 620–640 nm in acidified benzonitrile, the dyes provide an intense absorption at longer wavelength thanks to their oxidized π-conjugated systems. The π-electronic structure underwent twisting and bending, counteracting the electron-donating/withdrawing induction of its different substituents with a propensity to cancel its dipole moment and HOMO–LUMO charge-transfer coefficient. Zeta potential measurements of colloidal suspensions of sensitized TiO2 anatase nanoparticles outlined the difference in electric behavior of the organic ionic pairs at the surface of the nanoparticles: The noncoordinating or coordinating characters of the counterions were found governing the molecular density at the surface and the adsorption/desorption kinetics of the ionic pairs. Dye-sensitized solar cell (DSSC) measurements performed with I–/I3 – as redox shuttle outlined the availability of the dyes for solar cell sensitization and the conditions for best stability/efficiency of such π-conjugated structures according to the nature of the counterion.

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Effects of meso-M(PPh₃)₂Cl (M = Pd, Ni) substituents on the linear and third-order nonlinear optical properties of chalcogenopyrylium-terminated heptamethines in solution and solid states

et al. 2018

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Probing the Relative Photoinjection Yields of Monomer and Aggregated Dyes into ZnO Crystals

Cited by 3 publications

References 42 publications

Imaging Dye Aggregation in MK-2, N3, N749, and SQ-2 dye···TiO₂ Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes

Imaging Dye Aggregation in MK-2, N3, N749, and SQ-2 dye···TiO₂ Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes

Deep Blue Asymmetrical Streptocyanine Dyes: Synthesis, Spectroscopic Characterizations, and Ion-Specific Cooperative Adsorption at the Surface of TiO₂ Anatase Nanoparticles

Effects of meso-M(PPh₃)₂Cl (M = Pd, Ni) substituents on the linear and third-order nonlinear optical properties of chalcogenopyrylium-terminated heptamethines in solution and solid states

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Probing the Relative Photoinjection Yields of Monomer and Aggregated Dyes into ZnO Crystals

Cited by 3 publications

References 42 publications

Imaging Dye Aggregation in MK-2, N3, N749, and SQ-2 dye···TiO2 Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes

Imaging Dye Aggregation in MK-2, N3, N749, and SQ-2 dye···TiO2 Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes

Deep Blue Asymmetrical Streptocyanine Dyes: Synthesis, Spectroscopic Characterizations, and Ion-Specific Cooperative Adsorption at the Surface of TiO2 Anatase Nanoparticles

Effects of meso-M(PPh3)2Cl (M = Pd, Ni) substituents on the linear and third-order nonlinear optical properties of chalcogenopyrylium-terminated heptamethines in solution and solid states

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Imaging Dye Aggregation in MK-2, N3, N749, and SQ-2 dye···TiO₂ Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes

Imaging Dye Aggregation in MK-2, N3, N749, and SQ-2 dye···TiO₂ Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes

Deep Blue Asymmetrical Streptocyanine Dyes: Synthesis, Spectroscopic Characterizations, and Ion-Specific Cooperative Adsorption at the Surface of TiO₂ Anatase Nanoparticles

Effects of meso-M(PPh₃)₂Cl (M = Pd, Ni) substituents on the linear and third-order nonlinear optical properties of chalcogenopyrylium-terminated heptamethines in solution and solid states