High efficiency perovskite solar cells with tailorable surface wettability by surfactant

Perovskite solar cells based on nickel oxide (NiOx) attract tremendous attention and develop rapidly. Nevertheless, they are plagued by charge recombination and extraction loss at interfaces between the perovskite absorber and the charge transport layers. Herein, an ultrathin sodium dodecyl benzene sulfonate (SDBS) film is introduced between the perovskite absorber and the NiOx hole transport layer (HTL) to reduce interfacial and extraction losses. The modification on the NiOx HTL by SDBS surfactant can effectively tailor the quality of the perovskite film with larger grain size and better crystallinity by regulating the wettability of the NiOx surface with varied concentration of SDBS solution. Moreover, the charge separation and extraction in the perovskite/HTL interface are enhanced after SDBS treatment on NiOx HTL characterized by electrochemical impedance characterization. As a consequence, these benefits contribute to high power conversion efficiency (PCE) of 20.15%, in comparison with PCE of 16.26% for the reference device. It is hoped that this work will provide new perspectives for preparing perovskite solar cells with an unprecedented performance and the opportunity for commercialization.