Controlling growth of lead halide perovskites on organic semiconductor buffer layers

The performance of perovskite solar cells (PSCs) has been greatly influenced by the surface morphology and orientational growth of organometal halide perovskite, which can be controlled by buffer layers located underneath the perovskite layer. In this study, organic semiconductors such as rubrene and pentacene were selected as the buffer layer materials. We deposited CH₃NH₃PbI₃ (MAPbI₃) layers by the laser evaporation method onto the rubrene/pentacene bilayer, pentacene single layer, and rubrene single layer, respectively. The MAPbI₃-based solar cell with the rubrene/pentacene bilayer showed a better cell performance compared to other PSCs with rubrene and pentacene single buffer layers. The better PSC performance can be presumably attributed to an orientational growth behavior and a smoother surface of MAPbI₃ thin film on the rubrene/pentacene bilayer, as well as a more efficient hole transport in the organic bilayer.