Hierarchical Nanostructures CuBi2O4 Integrated with Polyaniline Nanofibrous for Boosting Hole Extraction in Carbon-Based Perovskite Solar Cells

Toward commercialization of carbon-based perovskite solar cells (C-PSCs), it is crucial to innovatively design inorganic hole transport layer materials that excel in extracting and transporting charge carriers to promote their photoelectric conversion efficiency (PCE). In this work, a novel and high-connectivity CuBi2O4-polyaniline nanofibrous (CuBi2O4-PN) reticular structure is created by integrating CuBi2O4 hierarchical microspheres (CuBi2O4 MS) with polyaniline nanofibrous. The introduction of CuBi2O4-PN as a hole transport layer (HTL) notably enhances the contact quality of the devices and substantially reduces the surface defects of C-PSCs. In a comparative analysis under identical experimental conditions, MAPbI(3) devices incorporating CuBi2O4-PN HTL demonstrated a PCE of 14.79%, achieving a 44.3% increase over the reference device (10.25%). CuBi2O4-treated C-PSCs retained 89.9% of their original PCE after 45 days in storage, and they demonstrated improved stability over a longer time frame. This remarkable improvement in device performance can be attributed to the effective suppression of nonradiative recombination and the enhancement of the carrier transfer process in the device. Additionally, the unique interconnected reticular structure of CuBi2O4-PN provides efficient pathways for hole transfer, significantly contributing to the enhanced efficiency of the device.