Homojunction Doping for Efficient Hole Extraction in Polymer Solar Cells

• Published in: Solar RRL Vol. 7; no. 2
• Main Authors: Feaugas, Francis, Nicolini, Tommaso, Roche, Gilles H., Hirsch, Lionel, Dautel, Olivier J., Wantz, Guillaume
• Format: Journal Article
• Language: English
• Published: Wiley 01.02.2023
• Subjects: Engineering Sciences; homojunctions; magic blue; organic photovoltaics; Physics; polymer doping; work function tuning; Polymer Doping -Organic Photovoltaic -Work Function Tuning -Magic Blue -Homojunction
• ISSN: 2367-198X; 2367-198X
• DOI: 10.1002/solr.202200815

Hole transporting layers (HTL) in polymer solar cells remain a subject of importance to enable enhanced efficiency and stability compared to the benchmark PEDOT:PSS. The design of an interlayer based on the same polymer as the one used in the bulk heterojunction (BHJ) is reported here. In this HTL, the polymer is doped, thus forming a so‐called homojunction. The conductivity of PTQ10 doped with magic blue is optimized for varying dopant concentrations. The resulting solar cells show competing power conversion efficiency as the widely used PEDOT:PSS and improved stability. This strategy opens the route toward the development of deep‐lying work function HTL and is promising for future BHJ materials with deep‐lying highest occupied molecular orbital polymers. Polymer solar cells are shown with a hole transport layer based on the same polymer as the one used in the bulk heterojunction. By doping, its work function is strongly affected to maximize the open‐circuit voltage. This homojunction approach is promising and applies to recent trending semiconducting polymers with deep‐lying energetics.