Asymmetric phthalocyanine-based hole-transporting materials: evaluating the role of heterocyclic units and PMMA additive

Two novel asymmetric phthalocyanine derivatives, ZnPc-1 and ZnPc-2, are synthesized to enhance charge transfer properties and mitigate deep-level traps on the perovskite surface using electron-rich nitrogen atoms. PSCs with ZnPc-1 and ZnPc-2 as hole-transporting materials (HTMs) achieved power conversion efficiencies (PCEs) of 12.11% and 8.98%, respectively. Incorporating a small amount of PMMA into the HTM solution significantly improved performance, resulting in PCEs of 16.2% and 12.5% for ZnPc-1 and ZnPc-2, respectively. The addition of PMMA enhances conductivity and prevents moisture intrusion, boosting both the efficiency and stability of PSCs.

ZnPcs with pyridine or imidazole units were synthesized as HTMs in PSCs. PMMA addition improved performance and stability, reaching 16.2% PCE for ZnPc-1.