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

Abstract

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 (CH₃NH₃PbI₃) 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 CH₃NH₃PbI₃ 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.