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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

Scan rate dependent cyclic voltammetryon MDMO-PPV.
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fig3: Scan rate dependent cyclic voltammetryon MDMO-PPV.

Mentions: In orderto characterize the electrochemical properties of the MDMO-PPV, cyclicvoltammetry was performed. Using this technique, detailed informationabout the oxidation/reduction processes as well as their kineticscan be obtained. First, cyclic voltammetry with different scan rateswas done. To avoid any interaction, for each measurement, the PE-SDCMwas moved to a different location, and measurements with scan ratesof 1, 3, 10, 30, and 100 mV s–1 were performed onsequentially addressed spots. All these cycles are presented togetherin Figure 3 to allow a direct comparison. Ascan be seen, the observed maximum of the current density increaseswhen increasing the scan rate, which can be easily explained by increasedmass transport at higher scan rates. Due to the strong overlappingof the experimental data, the curves corresponding to the first threepotential scan rates (up to 10 mV s–1) are displayedseparately in the inlet of Figure 3. Interestingobservations can be done, if looking at the shape of the current–voltagecurves as a function of the scan rate. For scan rates up to 10 mVs–1 two oxidation peaks are found (see inlet Figure 3). For the first experiment with a scan rate of1 mV s–1, the oxidation peaks are found at 0.8 and1.3 V. When increasing the speed of change of polarization up to 10mV s–1, the oxidation peaks are shifted to higherpotentials. The lower potential oxidation peak shifts to 0.83 V, whilethe higher potential oxidation peak shifts to 1.44 V. The scan ratedependent peak position suggests a kinetic hindrance of the electrochemicaloxidation process. As a result, higher potentials are needed for thesame oxidation process to occur. Moreover, in all three experiments,no clear reduction peak could be observed, but instead, a very broadnegative current distribution is noticeable. When comparing current–voltagecharacteristics measured with different polarization speeds, the differentbehavior of the reduction part of the voltammograms could be explainedby a dissolution process of the previously oxidized MDMO-PPV, whichbecomes more significant at lower polarization speeds where a secondoxidation peak was detected. For higher scan rates (30 and 100 mVs–1), only one clear oxidation peak is found witha maximum at 0.86 and 0.9 V, respectively. As compared to the previouslydiscussed case of low polarization speeds, the second oxidation peakis absent probably due to kinetic hindrance of the oxidation process.Additionally, for the high scan rate cases, a broad reduction peakcentered at 0.8 V is observed.


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)

Scan rate dependent cyclic voltammetryon MDMO-PPV.
© Copyright Policy
Related In: Results  -  Collection

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

fig3: Scan rate dependent cyclic voltammetryon MDMO-PPV.
Mentions: In orderto characterize the electrochemical properties of the MDMO-PPV, cyclicvoltammetry was performed. Using this technique, detailed informationabout the oxidation/reduction processes as well as their kineticscan be obtained. First, cyclic voltammetry with different scan rateswas done. To avoid any interaction, for each measurement, the PE-SDCMwas moved to a different location, and measurements with scan ratesof 1, 3, 10, 30, and 100 mV s–1 were performed onsequentially addressed spots. All these cycles are presented togetherin Figure 3 to allow a direct comparison. Ascan be seen, the observed maximum of the current density increaseswhen increasing the scan rate, which can be easily explained by increasedmass transport at higher scan rates. Due to the strong overlappingof the experimental data, the curves corresponding to the first threepotential scan rates (up to 10 mV s–1) are displayedseparately in the inlet of Figure 3. Interestingobservations can be done, if looking at the shape of the current–voltagecurves as a function of the scan rate. For scan rates up to 10 mVs–1 two oxidation peaks are found (see inlet Figure 3). For the first experiment with a scan rate of1 mV s–1, the oxidation peaks are found at 0.8 and1.3 V. When increasing the speed of change of polarization up to 10mV s–1, the oxidation peaks are shifted to higherpotentials. The lower potential oxidation peak shifts to 0.83 V, whilethe higher potential oxidation peak shifts to 1.44 V. The scan ratedependent peak position suggests a kinetic hindrance of the electrochemicaloxidation process. As a result, higher potentials are needed for thesame oxidation process to occur. Moreover, in all three experiments,no clear reduction peak could be observed, but instead, a very broadnegative current distribution is noticeable. When comparing current–voltagecharacteristics measured with different polarization speeds, the differentbehavior of the reduction part of the voltammograms could be explainedby a dissolution process of the previously oxidized MDMO-PPV, whichbecomes more significant at lower polarization speeds where a secondoxidation peak was detected. For higher scan rates (30 and 100 mVs–1), only one clear oxidation peak is found witha maximum at 0.86 and 0.9 V, respectively. As compared to the previouslydiscussed case of low polarization speeds, the second oxidation peakis absent probably due to kinetic hindrance of the oxidation process.Additionally, for the high scan rate cases, a broad reduction peakcentered at 0.8 V is observed.

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