Transparent and Conductive Polyimide‐Ionene Hybrid Interlayers for High Performance and Cost‐Effective Semitransparent Organic Solar Cells

Journal Article · Tue Apr 01 00:00:00 EDT 2025 · Advanced Materials

DOI:https://doi.org/10.1002/adma.202500450· OSTI ID:2574186

You, Zuhao; Wen, Junjie; Liu, Wenxu; Fink, Zachary; Wu, Xuefei; Seong, Hong‐Gyu; Wang, Yuxing; Zhang, Lei; Wang, Xu; Russell, Thomas P; Liu, Yao

The contradiction between high transmittance and favorable conductivity poses a great challenge in developing effective cathode interlayer (CIL) materials with sufficient thickness tolerance, which hinders the further advancement of organic solar cells (OSCs). Herein, a completely new class of alcohol processable polyimide-ionene hybrids (PIIHs) is proposed by melding pyromellitic diimide (PMD) subunits into imidazolium-based ionenes backbone covalently. These PIIHs, named PMD-DI and PMD-PD, boast high transparency, suitable energy levels, and decent conductivity. A higher PMD content endows PMD-PD with improved work function tunability, electrical properties, and crystallinity, enabling PMD-PD as CIL material with excellent thickness-insensitive characteristics, while simultaneously improving device stability significantly. Furthermore, PMD-PD also exhibits good compatibility with various electrodes and active layers, offering solar cell efficiencies of up to 19.91% and 19.29% with Ag and Cu cathodes, respectively. More importantly, the application of PMD-PD can improve the performance of semi-transparent OSCs without losing transmittance, thereby drastically enhancing the light utilization efficiency to 4.04% with an ultrathin, low-cost Cu cathode, that competes with leading optical modulation-free semitransparent OSCs with expensive Ag cathodes. This work opens a pathway to realize transparent and conductive interlayers by strategic molecular design, leading to highly efficient, stable, and cost-effective OSCs suitable for diverse applications.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Materials Sciences & Engineering Division (SC-22.2)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 2574186
• Journal Information: Advanced Materials, Journal Name: Advanced Materials Journal Issue: 15 Vol. 37
• Country of Publication: United States
• Language: English