Defect Passivation in Triple Cation Perovskite Solar Cells Through Crystallization Modulation with Isocyanate Additive

The efficacy of the perovskite photoactive layer is crucial in dictating the operational efficiency of the device. A novel additive engineering approach employing multifunctional 3,5-bis(trifluoromethyl)phenyl isocyanate (TFPC) within the perovskite precursor solution has been introduced to fabricate perovskite films of heightened quality, characterized by improved crystalline structure, hydrophobicity, surface uniformity, and enlarged grain dimensions. This methodology leads to a noticeable reduction in grain boundaries, trap densities, and hysteresis in resultant perovskite solar cells (PSCs). Optimal devices incorporating 4mg/mL TFPC additive demonstrate superior performance, yielding a significantly enhanced power conversion efficiency (PCE) of 20.43 % compared to control devices with the highest PCE of 16.53 %. Furthermore, the TFPC-modified devices at 4mg/mL exhibit augmented stability compared to control devices. In summary, the utilization of TFPC additive represents an efficacious strategy for fabricating high-efficiency, hysteresis-free, and stable PSCs.