Supramolecular Ladder-Type Conjugated Polymers Used as Hole Transporting Materials for High Efficiency Perovskite Solar Cells
Intramolecular S-O interaction is firstly adopted for designing conjugated polymer HTMs in perovskites solar cells. It can lock the flat conformation of polymer backbones that enables the polymer molecules pack closely in solid state, facilitating hole transporting. The solubility of conjugated polymers can be improved by introducing alkyloxy side chains, whereas their planarity in solid state will not be interfered. Furthermore, high hole mobility of 1.72×10-3 cm2 V-1 s-1 and suitable HOMO energy level of -5.43 eV can be achieved by side chains engineering. Finally, a PCE of 18.30% is obtained in P1-based dopant free devices, which most importantly, show much better long-term ambient stability than those based on traditional spiro-MeOTAD.