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Electrochemical Self-Assembly of Nanostructured CuSCN/Rhodamine B Hybrid Thin Film and Its Dye-Sensitized Photocathodic Properties.

Iwamoto T, Ogawa Y, Sun L, White MS, Glowacki ED, Scharber MC, Sariciftci NS, Manseki K, Sugiura T, Yoshida T - J Phys Chem C Nanomater Interfaces (2014)

Bottom Line: High loading of RB into the film has been achieved to reach a CuSCN:RB volume ratio of approximately 2:1.The crystallographic orientation of the nanostructure with respect to the substrate can be controlled.Photoelectrochemical study on the porous crystalline CuSCN obtained after the DMA treatment and sensitized with RB revealed sensitized photocathodic action under visible light illumination, indicating the potential usefulness of the porous CuSCN electrodes for construction of tandem dye-sensitized solar cells.

View Article: PubMed Central - PubMed

Affiliation: Center of Innovative Photovoltaic Systems (CIPS), Gifu University , Yanagido 1-1, Gifu, Gifu 501-1193, Japan.

ABSTRACT
Nanostructured hybrid thin films of CuSCN and rhodamine B (RB) are electrochemically self-assembled (ESA) by cathodic electrolysis in an ethanol/water mixture containing Cu(2+), SCN(-), and RB. By selecting the solvent, Cu(2+)/SCN(-) ratio, and the concentration of RB, we demonstrate several control parameters in the film formation. High loading of RB into the film has been achieved to reach a CuSCN:RB volume ratio of approximately 2:1. The RB solid could almost completely be extracted from the hybrid film by soaking the film in dimethylacetamide (DMA), leading to a large increase of the surface area. The crystallographic orientation of the nanostructure with respect to the substrate can be controlled. Efficient quenching of fluorescence of RB has been observed for the CuSCN/RB hybrid film, implying hole injection from RB excited state to CuSCN. Photoelectrochemical study on the porous crystalline CuSCN obtained after the DMA treatment and sensitized with RB revealed sensitized photocathodic action under visible light illumination, indicating the potential usefulness of the porous CuSCN electrodes for construction of tandem dye-sensitized solar cells.

No MeSH data available.


Related in: MedlinePlus

SEM pictures of the surface of the FTO glass substratesafter electrolysisfor 20 s (a) and 30 s (b) in an ethanol/water (75/25, v/v) mixed solutioncontaining 3 mM Cu(ClO4)2, 9 mM LiSCN, 0.1 MLiClO4, and 1.0 mM RB.
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fig2: SEM pictures of the surface of the FTO glass substratesafter electrolysisfor 20 s (a) and 30 s (b) in an ethanol/water (75/25, v/v) mixed solutioncontaining 3 mM Cu(ClO4)2, 9 mM LiSCN, 0.1 MLiClO4, and 1.0 mM RB.

Mentions: Our previous studies on electrodepositionof CuSCN employing arotating disk electrode revealed that the growth of CuSCN is typicallylimited by transport of complexes of Cu2+ and SCN– that form in solution, achieving practically 100% Faradaic efficiencyfor the formation of CuSCN.7 In aqueoussolutions, only a 1-to-1 complex is formed,7 while a neutral 1-to-2 complex is also formed and participates inthe electrochemical reaction in ethanolic solutions containing excessof SCN–.10 Thus, theoverall reaction is expressed by eq 1 for theaqueous solution and both eqs 1 and 2 operate in the ethanolic solution.12The chronoamperograms measuredduring theelectrodeposition can be seen in Figure 1.Following the initial rise of the current, diffusion-limited steady-statecurrent is reached both for the Cu2+ rich and SCN– rich solutions. However, a slightly higher current is seen for theSCN– rich solution. This should reflect the formationof a bis-coordinated Cu(II) thiocyanato complex which has a diffusioncoefficient that is somewhat higher than that of the monocoordinatedcomplex in ethanol as revealed in our electrochemical analysis.10 The addition of RB to the bath causes a slightdecrease of the steady-state current in the SCN– rich bath, whereas a slight increase of the current was observedin the Cu2+ rich bath, which could be caused by the chemicalinteraction of the complexes with RB molecules. Even though the additionof RB caused a slight decrease of Faradaic efficiency for the precipitationof CuSCN (vide infra), the film thickness increased linearly withthe consumed charge (see Figure 1S of SupportingInformation). As the current is almost constant, the film thicknesscan simply be controlled by the time of the electrolysis. However,it should be mentioned that the high addition of RB at 1.0 mM bringsabout a characteristic change in the initial profile of the current.In such baths, the current stays small in the beginning of the electrolysisthen abruptly increases to achieve the steady-state current. The surfaceof the FTO glass substrates was observed by SEM before and after thejump of the current (Figure 2). There is apparentlyno change before the jump as the bare surface of the FTO layer isseen. After the jump, tiny CuSCN particles are deposited, especiallyat the bottom of the valleys and along the ridges of the pyramidalFTO grains. Although the reason for the incubation time is unclear,it is probable that RB molecules are adsorbed on the FTO surface,hindering the nucleation of CuSCN.


Electrochemical Self-Assembly of Nanostructured CuSCN/Rhodamine B Hybrid Thin Film and Its Dye-Sensitized Photocathodic Properties.

Iwamoto T, Ogawa Y, Sun L, White MS, Glowacki ED, Scharber MC, Sariciftci NS, Manseki K, Sugiura T, Yoshida T - J Phys Chem C Nanomater Interfaces (2014)

SEM pictures of the surface of the FTO glass substratesafter electrolysisfor 20 s (a) and 30 s (b) in an ethanol/water (75/25, v/v) mixed solutioncontaining 3 mM Cu(ClO4)2, 9 mM LiSCN, 0.1 MLiClO4, and 1.0 mM RB.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4120671&req=5

fig2: SEM pictures of the surface of the FTO glass substratesafter electrolysisfor 20 s (a) and 30 s (b) in an ethanol/water (75/25, v/v) mixed solutioncontaining 3 mM Cu(ClO4)2, 9 mM LiSCN, 0.1 MLiClO4, and 1.0 mM RB.
Mentions: Our previous studies on electrodepositionof CuSCN employing arotating disk electrode revealed that the growth of CuSCN is typicallylimited by transport of complexes of Cu2+ and SCN– that form in solution, achieving practically 100% Faradaic efficiencyfor the formation of CuSCN.7 In aqueoussolutions, only a 1-to-1 complex is formed,7 while a neutral 1-to-2 complex is also formed and participates inthe electrochemical reaction in ethanolic solutions containing excessof SCN–.10 Thus, theoverall reaction is expressed by eq 1 for theaqueous solution and both eqs 1 and 2 operate in the ethanolic solution.12The chronoamperograms measuredduring theelectrodeposition can be seen in Figure 1.Following the initial rise of the current, diffusion-limited steady-statecurrent is reached both for the Cu2+ rich and SCN– rich solutions. However, a slightly higher current is seen for theSCN– rich solution. This should reflect the formationof a bis-coordinated Cu(II) thiocyanato complex which has a diffusioncoefficient that is somewhat higher than that of the monocoordinatedcomplex in ethanol as revealed in our electrochemical analysis.10 The addition of RB to the bath causes a slightdecrease of the steady-state current in the SCN– rich bath, whereas a slight increase of the current was observedin the Cu2+ rich bath, which could be caused by the chemicalinteraction of the complexes with RB molecules. Even though the additionof RB caused a slight decrease of Faradaic efficiency for the precipitationof CuSCN (vide infra), the film thickness increased linearly withthe consumed charge (see Figure 1S of SupportingInformation). As the current is almost constant, the film thicknesscan simply be controlled by the time of the electrolysis. However,it should be mentioned that the high addition of RB at 1.0 mM bringsabout a characteristic change in the initial profile of the current.In such baths, the current stays small in the beginning of the electrolysisthen abruptly increases to achieve the steady-state current. The surfaceof the FTO glass substrates was observed by SEM before and after thejump of the current (Figure 2). There is apparentlyno change before the jump as the bare surface of the FTO layer isseen. After the jump, tiny CuSCN particles are deposited, especiallyat the bottom of the valleys and along the ridges of the pyramidalFTO grains. Although the reason for the incubation time is unclear,it is probable that RB molecules are adsorbed on the FTO surface,hindering the nucleation of CuSCN.

Bottom Line: High loading of RB into the film has been achieved to reach a CuSCN:RB volume ratio of approximately 2:1.The crystallographic orientation of the nanostructure with respect to the substrate can be controlled.Photoelectrochemical study on the porous crystalline CuSCN obtained after the DMA treatment and sensitized with RB revealed sensitized photocathodic action under visible light illumination, indicating the potential usefulness of the porous CuSCN electrodes for construction of tandem dye-sensitized solar cells.

View Article: PubMed Central - PubMed

Affiliation: Center of Innovative Photovoltaic Systems (CIPS), Gifu University , Yanagido 1-1, Gifu, Gifu 501-1193, Japan.

ABSTRACT
Nanostructured hybrid thin films of CuSCN and rhodamine B (RB) are electrochemically self-assembled (ESA) by cathodic electrolysis in an ethanol/water mixture containing Cu(2+), SCN(-), and RB. By selecting the solvent, Cu(2+)/SCN(-) ratio, and the concentration of RB, we demonstrate several control parameters in the film formation. High loading of RB into the film has been achieved to reach a CuSCN:RB volume ratio of approximately 2:1. The RB solid could almost completely be extracted from the hybrid film by soaking the film in dimethylacetamide (DMA), leading to a large increase of the surface area. The crystallographic orientation of the nanostructure with respect to the substrate can be controlled. Efficient quenching of fluorescence of RB has been observed for the CuSCN/RB hybrid film, implying hole injection from RB excited state to CuSCN. Photoelectrochemical study on the porous crystalline CuSCN obtained after the DMA treatment and sensitized with RB revealed sensitized photocathodic action under visible light illumination, indicating the potential usefulness of the porous CuSCN electrodes for construction of tandem dye-sensitized solar cells.

No MeSH data available.


Related in: MedlinePlus