| 摘要: | The structural modification of hole-transporting materials (HTMs) is an effective strategy for enhancing the photovoltaic performance in perovskite solar cells (PSCs). Herein, we designed and synthesized a series of dithienopyran (DTP)-based HTMs (Me-H, Ph-H, CF3-H, CF3-mF, and CF3-oF) by substituting different functional group on the DTP unit and used them in fabricating PSCs. In comparing with Me-H having two methyl substituents on the dithienopyrano ring, the Ph-H having two phenyl substituents on the ring exhibits higher PCEs. Notably, the incorporation of trifluoromethyl groups in CF3-H endows the molecule with larger dipole moment, deeper HOMO energy level, better film morphology, closer molecular stacking, more efficient defect-passivation, enhanced hydrophobicity, and better photovoltaic performance when compared with the Ph-H counterpart. Furthermore, the HTMs of CF3-mF and CF3-oF, which feature fluorine-substituted triphenylamine, demonstrated excellent film-forming properties, more suitable energy levels, enhanced charge mobility, and improved passivation of the buried interface between HTMs and perovskite. As a result, PSCs employing CF3-mF and CF3-oF gave impressive PCE of 23.41% and 24.13%, respectively. In addition, the large-area (1.00 cm2) PSCs based on CF3-oF achieved a PCE of 22.31%. Moreover, the PSCs devices with CF3 series HTMs exhibited excellent long-term stability under different conditions. |
