Efficient and Stable Carbon-Based CsPbIBr₂ Solar Cells Using (3-Bromopropyl) Trimethylammonium Bromide

Although carbon-based all inorganic perovskite solar cells (C-PSC) reflect a balance between low cost and stability. However, the inherent structural defects of perovskite films and the energy level mismatch limit the performance of the device. Herein, (3-bromopropyl) trimethylammonium bromide (BPTAB) is used as the interface regulator in all inorganic CsPbIBr2 PSC. Thereby not only effectively reduces energy offset and facilitates hole extraction and delocalization, also improves photosensitive layer quality and inhibited carrier recombination. After gradient concentration optimization, 1 mM-BPTAB-C-PSC achieved a champion efficiency of 11.26% with a high open circuit voltage (1.31 V). In addition, due to the presence of a hydrophobic group (N+(CH3)3–), the unencapsulated device still maintains an original efficiency of 90% after aging for 900 h with excellent stability.