Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 31: Organic Electronics and Photovoltaics III: Mobile and Trapped Charges

HL 31.11: Talk

Tuesday, March 21, 2017, 12:15–12:30, ZEU 260

Significanlty enhanced charging efficiency for higher piezoelectricity in polymer ferroelectrets — •Xunlin Qiu — Department of Physics and Astronomy, University of Potsdam, 14469 Potsdam, Germany

Ferroelectrets are internally charged polymer foams or cavity-containing polymer-film systems. They are charged through a series of dielectric barrier discharges (DBDs) inside the cavities which interact with the internal polymer surfaces [1]. The breakdown strength of the gas strongly influences the charging process. A gas with a lower breakdown strength has a lower charging voltage, but leads to a lower remanent polarization. Charging in gases with higher breakdown strength requires higher voltage but allows higher remanent polarization. Here, a charging scheme involving gas exchange during charging is proposed [2]. The cavities of a tubular-channel fluoroethylenepropylene (FEP) ferroelectret are first filled with helium (lower breakdown strength), so that DBDs can be easily triggered by applying a relatively low voltage. The charging voltage should not be turned off until the gas inside the cavities has been replaced with nitrogen or air (having higher breakdown strength), in order to achieve higher remanent polarization. With the proposed charging scheme, the charging efficiency and hence the resultant piezoelectricity of ferroelectrets can be significantly enhanced.

[1] X. Qiu, W. Wirges and R. Gerhard, J. Appl. Phys. 110, 024108 (2008).

[2] X. Qiu, Appl. Phys. Lett. 109, 222903 (2016).