Performance Regulation of Perovskite Solar Cells via Bifacial Modification by F4-TCNQ and PFN-Br

Interfacial engineering is significantly important for achieving the high performance of perovskite solar cells. Exploring and developing universally efficient methods and strategies for interlayer optimization are greatly demanded by perovskite solar cells to reduce photovoltaic losses. By introducing small-molecule F4-TCNQ and conjugated polyelectrolyte PFN-Br as dopants, the performance regulation of inverted perovskite solar cells was systematically investigated. The results demonstrate the great effectiveness of F4-TCNQ to improve the VOC (from 0.959 to 1.032 V) and PFN-Br to enhance the current density (from 21.50 to 24.41 mA/cm2) of devices, as their ability to passivate defects, optimize energy-level alignment, and promote charge extraction. The synergistic/bifacial modification accomplished simultaneous enhancement of the parameters, thus improving the efficiency. The basic morphology and optical property of perovskite films were characterized to understand the performance parameters. This work provides a simple effective method for interface modification to reduce photovoltaic loss in perovskite solar cells and demonstrates the promising potential of bifacial modification to enhance the device performance.