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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.


Change of crystallographic orientation of CuSCN and CuSCN/RB hybridthin films by changing concentration of RB added to the SCN– rich and Cu2+ rich baths.
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fig5: Change of crystallographic orientation of CuSCN and CuSCN/RB hybridthin films by changing concentration of RB added to the SCN– rich and Cu2+ rich baths.

Mentions: Changes of XRD patternson RB addition are shown in Figure 4 for SCN– rich and Cu2+ rich baths. All these patternsindicate diffraction peaks assignedto β-CuSCN aside from those originating from SnO2 of the FTO substrate. The relative intensity of the diffractionpeaks of the film samples, however, are different from those of thepowder diffraction standard. It is also changes for different RB concentrationsand for SCN– rich (A) and Cu2+ rich (B)baths, indicating changes of their crystallographic orientation. Tworepresentative diffraction peaks arising from the (003) and the (101)planes are taken to evaluate the orientation change. While the (003)planes are perpendicular to the c-axis, the (101)planes are nearly parallel to the c-axis, crossingwith the (003) planes at 78.5° angle because of the elongatedunit cell structure. Therefore, the relative change of the (003) and(101) peak intensities is a good measure for examining how the c-axis of CuSCN is oriented with respect to the substrateplane. According to the method described in the literature,24 the orientation indices (OI) are calculatedas follows. The intensity factor (IF) of the standard powder sampleis calculated for the respective crystal planes as45taking the intensities indicated in ref (23). The IF of the film samples are calculated from the (003) and (101) peakcounts of each measured XRD pattern.67The ratio of the IF of the film with respectto that of the powder standard is defined as the OI.89When OI(hkl) islarger than 1, the film has a tendency to orient (hkl) planes in parallel with the substrate; when smaller than 1, justthe opposite. The calculated OIs are plotted in Figure 5. Pure CuSCN thin films electrodeposited without RB show highOI(003), indicating their preferential orientation of the c-axis perpendicular with the substrate, irrespective ofthe SCN– rich and Cu2+ rich bath compositions.Such preferential orientation nicely matches with the arguments fortheir morphological features described above, namely, the hexagonalfacet of the columnar grain in Figure 3a1 andthe bevels of the spiky grains in Figure 3b1corresponding to the (003) and (101) planes, respectively. Minor additionof RB to the bath then drastically increases the OI(101) upon decrease of OI(003), indicating the change of thecrystallographic orientation to lay down the c-axisin parallel with the substrate. Such preference is most prominentwhen [RB] = 0.3 mM, for both the SCN– rich and Cu2+ rich baths. However, the higher addition of RB abruptlychanges the orientation back to the one in which the c-axis is perpendicular with the substrate in the case of the SCN– rich bath, whereas the OI(101) value onlymoderately decreases for the Cu2+ rich bath. Consequently,highly porous CuSCN thin films with totally different crystallographicorientations, namely, the c-axis perpendicular andparallel with the substrate are obtained for the highest end of theRB addition to the SCN– rich and Cu2+ rich baths, respectively. The reason for the complex change of thecrystallographic orientation is unclear. However, it is obvious thatsuch changes are caused by the difference of the chemical stabilityof the facets of CuSCN crystals in different environments, not onlyby the SCN–/Cu2+ balance but also bythe added RB molecules.


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)

Change of crystallographic orientation of CuSCN and CuSCN/RB hybridthin films by changing concentration of RB added to the SCN– rich and Cu2+ rich baths.
© Copyright Policy
Related In: Results  -  Collection

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fig5: Change of crystallographic orientation of CuSCN and CuSCN/RB hybridthin films by changing concentration of RB added to the SCN– rich and Cu2+ rich baths.
Mentions: Changes of XRD patternson RB addition are shown in Figure 4 for SCN– rich and Cu2+ rich baths. All these patternsindicate diffraction peaks assignedto β-CuSCN aside from those originating from SnO2 of the FTO substrate. The relative intensity of the diffractionpeaks of the film samples, however, are different from those of thepowder diffraction standard. It is also changes for different RB concentrationsand for SCN– rich (A) and Cu2+ rich (B)baths, indicating changes of their crystallographic orientation. Tworepresentative diffraction peaks arising from the (003) and the (101)planes are taken to evaluate the orientation change. While the (003)planes are perpendicular to the c-axis, the (101)planes are nearly parallel to the c-axis, crossingwith the (003) planes at 78.5° angle because of the elongatedunit cell structure. Therefore, the relative change of the (003) and(101) peak intensities is a good measure for examining how the c-axis of CuSCN is oriented with respect to the substrateplane. According to the method described in the literature,24 the orientation indices (OI) are calculatedas follows. The intensity factor (IF) of the standard powder sampleis calculated for the respective crystal planes as45taking the intensities indicated in ref (23). The IF of the film samples are calculated from the (003) and (101) peakcounts of each measured XRD pattern.67The ratio of the IF of the film with respectto that of the powder standard is defined as the OI.89When OI(hkl) islarger than 1, the film has a tendency to orient (hkl) planes in parallel with the substrate; when smaller than 1, justthe opposite. The calculated OIs are plotted in Figure 5. Pure CuSCN thin films electrodeposited without RB show highOI(003), indicating their preferential orientation of the c-axis perpendicular with the substrate, irrespective ofthe SCN– rich and Cu2+ rich bath compositions.Such preferential orientation nicely matches with the arguments fortheir morphological features described above, namely, the hexagonalfacet of the columnar grain in Figure 3a1 andthe bevels of the spiky grains in Figure 3b1corresponding to the (003) and (101) planes, respectively. Minor additionof RB to the bath then drastically increases the OI(101) upon decrease of OI(003), indicating the change of thecrystallographic orientation to lay down the c-axisin parallel with the substrate. Such preference is most prominentwhen [RB] = 0.3 mM, for both the SCN– rich and Cu2+ rich baths. However, the higher addition of RB abruptlychanges the orientation back to the one in which the c-axis is perpendicular with the substrate in the case of the SCN– rich bath, whereas the OI(101) value onlymoderately decreases for the Cu2+ rich bath. Consequently,highly porous CuSCN thin films with totally different crystallographicorientations, namely, the c-axis perpendicular andparallel with the substrate are obtained for the highest end of theRB addition to the SCN– rich and Cu2+ rich baths, respectively. The reason for the complex change of thecrystallographic orientation is unclear. However, it is obvious thatsuch changes are caused by the difference of the chemical stabilityof the facets of CuSCN crystals in different environments, not onlyby the SCN–/Cu2+ balance but also bythe added RB molecules.

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.