Enhanced Stability and Optimized Morphology Induced by Electric‐Field‐Assisted Annealing of Bulk Heterojunction Solar Cells. Issue 10 (27th June 2019)

• Record Type: Journal Article
• Authors: Vijayan, Raaghesh; Azeez, Abdul; Narayan, Kavassery S.
• Is Part Of: Solar RRL. Volume 3:Issue 10(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-27
• Subjects: electric-field-assisted annealing -- noise spectroscopy -- organic solar cells -- stability -- vertical phase segregation; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.201900120
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : The utility of electric fields during the bulk heterojunction (BHJ) film drying process for tuning the morphology and stability of the device is demonstrated. An external electric‐field‐assisted annealing (EFTA) treatment is used to engineer the stability of amorphous donor polymer‐based BHJs without compromising device performance. Residual additive in the device post fabrication is a major source of degradation. Thermal annealing of an active layer effectively removes residual additive, which in case of amorphous polymer donor‐based BHJs, however, leads to unfavorable changes in the morphology. The detrimental effect of thermal annealing in amorphous donor polymer‐based solar cells is mitigated by the presence of an electric field during the drying stage. The complete removal of additive is ensured by this treatment procedure and leads to improved packing and a rigid morphology. The structural stability is reflected in the performance parameters monitored over the long term and electrical noise measurements. The magnitude and polarity of the applied electric field are observed to control the vertical distribution of donor and acceptor components. Abstract : Electric field treatment during thermal annealing is used to control the vertical phase segregation of components in the organic solar cells. Residual additive solvent remaining in the active layer, which is responsible for unfavorable morphological changes, is effectively removed by this treatment. Maintaining the morphology of the active layer over time reflects long‐term stability of solar cells.