We have investigated a series of non-conjugated polyelectrolytes (NPEs) which are based on a polyethylenimine (PEI) backbone with various counterions, such as Br- I- and BIm4-, as interfacial layers at the electrodes of solar cells and transistor devices to improve the power conversion efficiency (PCE) and device performance. This new series of NPEs with different counterions are capable of forming electric dipoles at NPE/metal electrode interfaces; as a consequence tuning of the energy levels, and work function (WF) of the electrodes is possible. Using this approach, the PCE of organic solar cells could be improved from 1.05% (without NPEs) to 6.77% (with NPEs) while the charge carrier mobility and on/off ratio of FET devices could be improved, showing the broad utility of this type of material. This study provides a novel approach towards investigating the influence of ions on interfacial dipoles and electrode WFs in solution-processed semiconducting devices.
Bibliographical noteFunding Information:
This research was supported by the National Research Foundation of Korea (2017R1C1B1010627 and 2017R1A2B2012971) and through the Kyung Hee University Research Equipment Support Project (KHU-20181297) This work was supported by Busan Institute of Science and Technology Evaluation and Planning (BISTEP) grant (2019 Busan Open Lab. Program) funded by the Korea government (Ministry of Trade, Industry 5 and Energy) and Busan metropolitan city. This research was also supported by the National Research Foundation of Korea (NRF) Grant funded by the Ministry of Science and ICT for First-Mover Program for Accelerating Disruptive Technology Development (NRF-2018M3C1B9088457).
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)