Fluorine substitution in molecular design has become an effective strategy for improving the overall performance of organic photovoltaics. In this study, three low-cost small molecules of spiro-linked hole transporting materials (SFX-o-2F, SFX-m-2F, and SFX-p-2F) endowed with two-armed triphenylamine moieties were synthesized via tuning of the fluorine substitution position, and they were employed for use in highly efficient perovskite solar cells (PSCs). Despite the fluorine substitution position playing a negligible role in the optical and electrochemical properties of the resulting small molecules, the photovoltaic performance thereof was observed to vary significantly. The planar n-i-p PSCs based on SFX-m-2F demonstrated superior performance (18.86%) when compared to that of the corresponding SFX-o-2F (9.7%) and SFX-p-2F (16.33%) under 100 mW cm^-2 AM1.5G solar illumination, which is competitive with the performance of the benchmark spiro-OMeTAD-based device (18.98%). Moreover, the SFX-m-2F-based PSCs were observed to be more stable than the spiro-OMeTAD-based devices under ambient conditions. The improved performance of SFX-m-2F is primarily associated with improved morphology, more efficient hole transport, and extraction characteristics at the perovskite/HTM interface. This work demonstrated the application of fluorination engineering to the tuning of material film morphology and charge transfer properties, showing the promising potential of fluorinated SM-HTMs for the construction of low-cost, high-efficiency PSCs.

分子设计中的氟取代已成为改善有机光伏整体性能的有效策略。在这项研究中，三种低成本的螺环连接空穴传输材料小分子（SFX- o -2F，SFX- m -2F和SFX- p -2F通过调节氟取代位置合成了具有二臂三苯胺部分的α），并将其用于高效钙钛矿太阳能电池（PSC）。尽管氟取代位置在所得小分子的光学和电化学性质中起可忽略的作用，但观察到其光电性能显着变化。在100 mW cm ^-2下，基于SFX- m -2F的平面压区PSC与相应的SFX- o -2F（9.7％）和SFX- p -2F（16.33％）相比，表现出优异的性能（18.86％）。AM1.5G太阳照度，这是与基准的性能的竞争螺- OMeTAD为基础的设备（18.98％）。此外，观察到基于SFX- m -2F的PSC在环境条件下比基于spiro-OMeTAD的设备更稳定。SFX- m -2F的改进性能主要与钙钛矿/ HTM界面处的形态改善，空穴传输效率更高和萃取特性有关。这项工作证明了氟化工程技术在调节材料膜形态和电荷转移性质方面的应用，显示了氟化SM-HTM在构建低成本，高效率PSC方面的潜在潜力。