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Thermal Development of Free Volumes in Nafion Membrane

100%

Melikhova O., Čížek J., Košinová L., Hruška P.

Acta Physica Polonica A

2017

vol. 132

issue 5

1538-1542

In this work we employed positron lifetime spectroscopy for investigation of the thermal development of free volumes in H⁺ Nafion membrane over a broad range of temperatures from -150 to 150°C. Positron lifetime studies were combined with differential scanning calorimetry. Size distribution of free volumes was determined from ortho-positronium contribution to positron lifetime spectra. Our investigations revealed that the mean size of free volume holes strongly increases with temperature. On the other hand, the width of the size distribution and the positronium yield decreases with temperature. Transition temperatures corresponding to a change in the slope of the temperature dependence of ortho-positronium lifetime were identified. Results of positron lifetime spectroscopy agree well with the curve obtained by differential scanning calorimetry.

Continuous lateral gradients in film morphology for position sensitive detection and organic solar cell optimization

84%

Campoy-Quiles M., Randon V., Mróz M. M., Jarzaguet M., Garriga M., Cabanillas-González J.

Organic Photonics and Photovoltaics

2013

vol. 1

11-23

We present a method to fabricate binary organic donor and acceptor blends exhibiting a controlled lateral gradient in morphology. Upon combining photometry, ellipsometry and Xray maps together with photoinduced absorption measurements, we show how the gradual exposure to solvent vapor results in a varying degree of polymer crystallinity for the polythiophene/soluble fullerene system along one direction. These morphologically graded samples are characterized by a spectral photoresponse that depends on the specific location in the area of the device where the light beam impinges, a property that stands as proof-of-concept for position sensitive detection. Moreover, we demonstrate that the development of graded morphologies is an effective one-step method which allows for fast performance optimization of organic solar cells. Finally, the appropriateness of eight different solvents for morphology control via vapor annealing is evaluated in a time-effective way using the advanced method, which helps to identify boiling point and solubility as the key processing parameters.

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1 Acta Physica Polonica A

1 Organic Photonics and Photovoltaics

1 2017

1 2013

1 Cabanillas-González J.

1 Campoy-Quiles M.

1 Garriga M.

1 Hruška P.

1 Jarzaguet M.

1 Košinová L.

1 Melikhova O.

1 Mróz M. M.

1 Randon V.

1 Čížek J.

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Thermal Development of Free Volumes in Nafion Membrane

Continuous lateral gradients in film morphology for position sensitive detection and organic solar cell optimization