One-step constructed dual interfacial layers for stable perovskite solar cells

The highly efficient perovskite solar cells (PSCs) along with excellent long-term stability can be obtained by fabricating two-dimensional (2D) perovskites (PVKs) over the three-dimensional (3D) PVKs film. However, the additional step of forming 2D PVKs before depositing the hole/electron transporting layer would make the device fabrication processes complicated, increasing costs for the manufacture of PSCs. In the present work, 2D PVKs were in-situ formed on surface of the 3D PVKs film by a self-assembly method, together with the deposition of the hole transporting material (HTM) at the same time, which tremendously simplified the fabrication of PSCs based on 3D PVKs/2D PVKs. Based on the one-step constructed 2D PVKs/HTM dual interfacial layers , density of trap states in devices were decreased remarkably owing to efficient interfacial passivation . In the meantime, the hydrophobicity , conductivity and hole extraction ability of the HTM were generally improved, enhancing the operational stability and performance of the solar cells. Thus, the corresponding solar cells increased 10% of average power conversion efficiency , where the highest open circuit voltage is up to 1.174 V. After 672 h of exposure under full 1-sun simulation in ambient conditions, the device still retained more than 82% of its initial PCE which was almost 50% higher than that of the control device.