| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1400627 | European Polymer Journal | 2011 | 8 Pages |
We show that both the morphology and crystal structure of regioregular poly(3-hexylthiophene) (RR-P3HT) films in organic field effect transistor (OFET) devices with top surface contacts are altered, when an electric field is applied. Grazing incidence X-ray diffraction (GIXD) analysis reveals a dramatic decrease in structural order in the non-linear current regime and, by contrast, much less pronounced structural changes of the (h 0 0) peaks in the linear current regime. Using for the first time resonance soft X-ray reflectivity (RSoXR) on RR-P3HT to avoid radiation damaged and to enhance the scope of the attained depth resolved information, we show that these changes are located in a several tens of nanometer thin sub-surface layer of the active polymer in the device. Furthermore, the RSoXR data reveal that the changes are strongly related to the C 1s → π∗ and C 1s → σ∗-resonances. In situ AFM measurements of the RR-P3HT device surface support the reciprocal space analysis results by showing a substantial softening and lateral expansion of the RR-P3HT films, when 20 V are applied between the contacts. These morphological and structural changes are partially reversible in nature.
Graphical abstractWe show by novel resonance soft X-ray reflectivity and AFM measurements that both the morphology and crystal structure of regioregular poly(3-hexylthiophene) films in organic field effect transistor (OFET) devices with top surface contacts are altered, when an electric field is applied.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Electric field affects RR-P3HT in OFET devices with top surface contacts. ► Both morphology and crystal structure of RR-P3HT films are altered. ► First resonance soft X-ray reflectivity data on RR-P3HT films in electric field. ► Changes are strongly related to the C 1s → π∗ and C 1s → σ∗-resonances. ► AFM shows softening when 20 V are applied.
