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Photoelectrochemical and Electrochemical Characterization of Sub-Micro-Gram Amounts of Organic Semiconductors Using Scanning Droplet Cell Microscopy.

Kollender JP, Gasiorowski J, Sariciftci NS, Mardare AI, Hassel AW - J Phys Chem C Nanomater Interfaces (2014)

Bottom Line: The most attractive features of the PE-SDCM are represented by the possibility of addressing small areas on the investigated substrate and the need of small amounts of electrolyte.A very small amount (ng) of the material under study is sufficient for a complete electrochemical and photoelectrochemical characterization due to the scanning capability of the cell.The electrochemical behavior of the polymer was studied in detail using potentiostatic and potentiodynamic investigations as well as electrochemical impedance spectroscopy.

View Article: PubMed Central - PubMed

Affiliation: Institute for Chemical Technology of Inorganic Materials, Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, and Christian Doppler Laboratory for Combinatorial Oxide Chemistry at the Institute for Chemical Technology of Inorganic Materials, Johannes Kepler University Linz , Altenberger Str. 69, 4040 Linz, Austria.

ABSTRACT
A model organic semiconductor (MDMO-PPV) was used for testing a modified version of a photoelectrochemical scanning droplet cell microscope (PE-SDCM) adapted for use with nonaqueous electrolytes and containing an optical fiber for localized illumination. The most attractive features of the PE-SDCM are represented by the possibility of addressing small areas on the investigated substrate and the need of small amounts of electrolyte. A very small amount (ng) of the material under study is sufficient for a complete electrochemical and photoelectrochemical characterization due to the scanning capability of the cell. The electrochemical behavior of the polymer was studied in detail using potentiostatic and potentiodynamic investigations as well as electrochemical impedance spectroscopy. Additionally, the photoelectrochemical properties were investigated under illumination conditions, and the photocurrents found were at least 3 orders of magnitude higher than the dark (background) current, revealing the usefulness of this compact microcell for photovoltaic characterizations.

No MeSH data available.


Related in: MedlinePlus

Cyclicvoltammograms of MDMO-PPV for various reverse potentials.All scans with reverse potentials up to 1.5 V and scans with reversepotentials up to 0.95 V (inset).
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fig4: Cyclicvoltammograms of MDMO-PPV for various reverse potentials.All scans with reverse potentials up to 1.5 V and scans with reversepotentials up to 0.95 V (inset).

Mentions: In order to get a betterunderstanding of the polymer oxidationand reduction processes, a series of cyclic voltammograms was measuredwith a scan rate of 10 mV s–1 on a single spot.In this experiment, the maximum potential was incrementally increasedin steps of 0.05 V up to the final potential of 1.5 V. The resultsare plotted in Figure 4. During experiments,all curves with the maximum potential up to 0.8 V, showed only backgroundcurrent. This is observable in the inlet of Figure 4, where only the first five experiments (with final potentialup to 0.95 V) are presented. In the scan with a final potential of0.85 V, a sharp and well-defined peak with maximum at 0.84 V, wasfound. In the next scan, with a final potential of 0.9 V the intensityof this peak reduces and a broadening can be observed. Additionally,a second anodic peak can now be observed at 0.68 V. The presence ofthis new peak is related to an initial oxidation of the MDMO-PPV.This peak was not measured before, probably due to the formation ofan interfacial barrier on the polymer surface causing the previouslydiscussed peak at 0.84 V. The next scan with a final potential of0.95 V has only the initial oxidation peak centered at 0.68 V witha slightly higher current density than in the previous scan. For finalpotentials above 0.95 V, the peak characterizing the first oxidationstep shifts toward higher potentials. The current density value atthe peak maximum increases gradually up to 0.03 mA cm–2 in the case of the scan with the highest final potential. For thelast three measured scans (1.4–1.5 V) the position of the firstoxidation peak is shifted for about 50 mV up to 0.8 V for each additionalexperiment. For cyclic voltammograms with the final potential above1 V, a strong increase in the current can be observed at the end ofthe anodic sweep. This peak can be related to a second oxidation stepof the polymer. All performed cyclic voltammograms that show a clearFaradaic current have a rather undefined broad reduction peak. Whenincreasing the maximum potentials of the scans, the maximum currentdensity of the reductive current is shifted toward more positive potentials.


Photoelectrochemical and Electrochemical Characterization of Sub-Micro-Gram Amounts of Organic Semiconductors Using Scanning Droplet Cell Microscopy.

Kollender JP, Gasiorowski J, Sariciftci NS, Mardare AI, Hassel AW - J Phys Chem C Nanomater Interfaces (2014)

Cyclicvoltammograms of MDMO-PPV for various reverse potentials.All scans with reverse potentials up to 1.5 V and scans with reversepotentials up to 0.95 V (inset).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4120669&req=5

fig4: Cyclicvoltammograms of MDMO-PPV for various reverse potentials.All scans with reverse potentials up to 1.5 V and scans with reversepotentials up to 0.95 V (inset).
Mentions: In order to get a betterunderstanding of the polymer oxidationand reduction processes, a series of cyclic voltammograms was measuredwith a scan rate of 10 mV s–1 on a single spot.In this experiment, the maximum potential was incrementally increasedin steps of 0.05 V up to the final potential of 1.5 V. The resultsare plotted in Figure 4. During experiments,all curves with the maximum potential up to 0.8 V, showed only backgroundcurrent. This is observable in the inlet of Figure 4, where only the first five experiments (with final potentialup to 0.95 V) are presented. In the scan with a final potential of0.85 V, a sharp and well-defined peak with maximum at 0.84 V, wasfound. In the next scan, with a final potential of 0.9 V the intensityof this peak reduces and a broadening can be observed. Additionally,a second anodic peak can now be observed at 0.68 V. The presence ofthis new peak is related to an initial oxidation of the MDMO-PPV.This peak was not measured before, probably due to the formation ofan interfacial barrier on the polymer surface causing the previouslydiscussed peak at 0.84 V. The next scan with a final potential of0.95 V has only the initial oxidation peak centered at 0.68 V witha slightly higher current density than in the previous scan. For finalpotentials above 0.95 V, the peak characterizing the first oxidationstep shifts toward higher potentials. The current density value atthe peak maximum increases gradually up to 0.03 mA cm–2 in the case of the scan with the highest final potential. For thelast three measured scans (1.4–1.5 V) the position of the firstoxidation peak is shifted for about 50 mV up to 0.8 V for each additionalexperiment. For cyclic voltammograms with the final potential above1 V, a strong increase in the current can be observed at the end ofthe anodic sweep. This peak can be related to a second oxidation stepof the polymer. All performed cyclic voltammograms that show a clearFaradaic current have a rather undefined broad reduction peak. Whenincreasing the maximum potentials of the scans, the maximum currentdensity of the reductive current is shifted toward more positive potentials.

Bottom Line: The most attractive features of the PE-SDCM are represented by the possibility of addressing small areas on the investigated substrate and the need of small amounts of electrolyte.A very small amount (ng) of the material under study is sufficient for a complete electrochemical and photoelectrochemical characterization due to the scanning capability of the cell.The electrochemical behavior of the polymer was studied in detail using potentiostatic and potentiodynamic investigations as well as electrochemical impedance spectroscopy.

View Article: PubMed Central - PubMed

Affiliation: Institute for Chemical Technology of Inorganic Materials, Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, and Christian Doppler Laboratory for Combinatorial Oxide Chemistry at the Institute for Chemical Technology of Inorganic Materials, Johannes Kepler University Linz , Altenberger Str. 69, 4040 Linz, Austria.

ABSTRACT
A model organic semiconductor (MDMO-PPV) was used for testing a modified version of a photoelectrochemical scanning droplet cell microscope (PE-SDCM) adapted for use with nonaqueous electrolytes and containing an optical fiber for localized illumination. The most attractive features of the PE-SDCM are represented by the possibility of addressing small areas on the investigated substrate and the need of small amounts of electrolyte. A very small amount (ng) of the material under study is sufficient for a complete electrochemical and photoelectrochemical characterization due to the scanning capability of the cell. The electrochemical behavior of the polymer was studied in detail using potentiostatic and potentiodynamic investigations as well as electrochemical impedance spectroscopy. Additionally, the photoelectrochemical properties were investigated under illumination conditions, and the photocurrents found were at least 3 orders of magnitude higher than the dark (background) current, revealing the usefulness of this compact microcell for photovoltaic characterizations.

No MeSH data available.


Related in: MedlinePlus