Montmorillonite as bifunctional buffer layer material for hybrid perovskite solar cells with protection from corrosion and retarding recombination

4-tert-Butylpyridine (TBP) has been an important component in hole transport layer for hybrid perovskite solar cells. However, our study shows that TBP can corrode the perovskite absorption layer (CH(3)NH(3)Pbl(3)) and interfere with the stability of the solar cells. To address this problem, montmorillonite (MMT) was used to form a buffer layer on top of the hole transport layer. XRD results revealed that TBP was intercalated in the MMT structure and UV-vis spectroscopy analysis revealed that this structure could prevent the corrosion of the CH(3)NH(3)Pbl(3) layer. Moreover, the MMT buffer layer could limit charge recombination in the solar cells. A delayed corrosion led to an increased current density owing to enhanced absorption, while a reduced charge recombination led to an increased fill factor and open voltage circuit values. Consequently, the corresponding efficiency largely increased from 9.0% to 11.9%, with an improvement of 32.2%. Therefore, the application of MMT as a bifunctional buffer coating layer on the hole transport layer is a useful strategy for preparing highly efficient hybrid perovskite solar cells with anti-corrosion and delayed charge recombination properties.