Spiro-thiophene derivatives as hole-transport materials for perovskite solar cells

This work reports a promising hole transportingmaterial using a spirothiophene derivative with 4,4'-spirobi[cyclopenta[2,1-b;3,4-b']dithiophene] as the spiro core for perovskite solar cells, exhibiting an overall power conversion efficiency of 10.4% with an open circuit voltage of 0.94 V, and a short circuit current density of 16.54 mA cm(-2) under standard testing conditions.