Interface engineering via pre-engineered black phosphorus quantum dots for highly efficient carbon-based hole-transport-layer-free perovskite solar cells

ions released from BPQDs effectively passivate defects on the perovskite surface, suppressing nonradiative recombination. Consequently, the optimized devices achieve a power conversion efficiency (PCE) of 17.08%, which is 24.1% and 11.9% higher than that of control devices without an interlayer (13.76%) and with a pristine BPQDs interlayer (15.26%), respectively. Furthermore, the encapsulated devices demonstrate improved operational stability, retaining 89.1% of their initial PCE after 360 hours under 1-sun illumination at 85 °C and 85% relative humidity.