Synthesis and Properties of Dithiafulvenyl Functionalized Spiro[fluorene-9,9'-xanthene] Molecules.

Two spiroannulated molecular structures with dithiafulvenyl units functionalized at the 2,2',7,7'- (SFX-DTF1) and 2,3',6,'7- (SFX-DTF2) positions of a spiro[fluorene-9,9'-xanthene] core were synthesized. Studies revealed the hole mobility was significantly influenced by the dithiafulvenyl functionalized positions in the molecular structure. To explore their primary applications as hole-transporting materials in perovskite solar cells, SFX-DTF1-based devices exhibited a power conversion efficiency of 10.67% without the use of p-type dopants, yielding good air stability.