Aggregation-Induced Doping Enhancement Enabled by Non-Covalent Conformation Locking on Conjugated Polyelectrolyte...

The development of anode interlayers (AIL) with a non-corrosive nature and good compatibility with large-area fabrication techniques has long been an important topic in the field of organic solar cells (OSCs). However, most AIL materials suffer from low doping density, which results in poor conductivity, ultimately degrading their performances. Here, we demonstrate an aggregation-induced doping enhancement in conjugated polyelectrolytes (CPEs), enabled by the introduction of non-covalent S-O and S-F interactions as conformational locks to yield coplanar conjugated backbones. The characterization results of condensed structure revealed that the ordered and compact molecular aggregation of CPE films can induce a pronounced p-doping effect, which significantly enhances charge-transporting capabilities. In particular, the PEP-2SF exhibited a π-π stacking distance of 3.53 Å and showed an exceptional conductivity of 4.34 × 10^{- 2} S/m after being doped by polyoxometalate (POM). OSCs modified by the PEP-2SF-based AIL exhibited a power conversion efficiency (PCE) of 20.28%. Moreover, the high conductivity enables excellent thickness insensitivity and good compatibility of PEP-2SF:P with large-area processing methods. A 1.2-cm² device was fabricated based on blade-coated PEP-2SF:P, exhibiting a PCE of 17.31%. Our results suggest that aggregation-induced doping enhancement of CPEs will provide an effective approach for developing high-performance AIL materials.