Inverse-architecture perovskite solar cells with 5,6,11,12-tetraphenylnaphthacene as a hole conductor

5,6,11,12-Tetraphenylnaphthacene (rub), an organic small molecular semiconductor widely used in organic field-effect transistors and organic light-emitting diodes, was introduced into MAPbI₃-based inverse-architecture perovskite solar cells as a hole transport layer due to its high hole mobility, good hydrophobic properties, favourable highest occupied molecular orbital (HOMO), low-cost, and low-temperature treatment process of rub. A high open-circuit voltage of 0.96 V, short-circuit current of 22 mA cm^-2, and power conversion efficiency of 14.3% were achieved in the inverted planar heterostructure perovskite solar cells based on the rub hole-transport layer due to the HOMO energy level matching between rub and MAPbI₃, large hole conductivity of rub, and large crystalline grain size of MAPbI₃ formed on rub.