Conjugated Polyelectrolyte Combined with Ionic Liquid as the Hole Transport Layer for Efficient Inverted Perovskite Solar Cells

Conjugated polyelectrolytes (CPEs) are promising hole transport materials for perovskite solar cells, whereas their severe intermolecular aggregation significantly affects the device performance. Here, long-chain alkyl imidazolium ionic liquid (IL) of 1-dodecyl-3-methylimidazolium bromide ([C 12 mim]Br) and conjugated potassium poly[3-(4-carboxylatebutyl)thiophene (P3CT-K) combined with different mass ratios. The UV–vis spectra dynamic light scattering studies indicate that behavior P3CT-K is suppressed by IL, thus obtaining a smoother layer latter fabrication, which efficiently improves film quality absorber enhances at interface. As consequence, inverted PSCs based on P3CT-K/IL as HTL show considerable improvement in power conversion efficiency (PCE), from 16.21% to 18.81%, compared pristine device. These findings IL can effectively inhibit CPEs, providing new pathway further improve performance CPEs interlayer.