Hexafluoroisopropanol modified MXene for perovskite surface remodeling and interfacial dipole effect enhancement

The development of high-efficiency and stable perovskite (PVK) solar cells (PSCs) still faces the challenge of non-ideal interfaces between PVK and charge transport layers. Herein, the hexafluoroisopropanol (HFIP) modified two-dimensional Ti3C2Tx MXene is custom-made (MX-HFIP) and employed as the interlayer between the PVK and hole transport layer (HTL) interface by forming hydrogen bonds. The MX-HFIP serves to reinforce the interface contact and remodel the surface of PVK, leading to a high-quality PVK film with a significantly reduced defect density, suppressed nonradiative recombination, and inhibited invasion of water and oxygen. Moreover, the synergistic effect of MXene and HFIP results in an enhanced interfacial dipole effect and an optimized energy-level alignment, thereby increasing the driving force for charge extraction and transport at the PVK/HTL interface. Therefore, the MX-HFIP treated PSC achieves a substantially-enhanced power conversion efficiency (PCE) of 22.33 %, as compared to 20.05 % of the untreated device. Besides, the MX-HFIP treated PSC delivers significantly enhanced stabilities, with 88 % of its initial PCE after 1656 h of storage at 25 °C under 30 %⁓40 % relative humidity. These findings demonstrate the advancement using fluorine-rich molecule modified MXene to improve interfacial properties for enhancing performances and stabilities of optoelectronic devices. [Display omitted] •MX-HFIP is employed to modify the PVK/HTL interface.•MX-HFIP reinforces the interface contact by forming hydrogen bonds.•PVK surface is remodeled and film quality is improved.•Interfacial dipole effect is enhanced to promote charge extraction and transport.•Performances and stabilities of PSCs are substantially enhanced.