Tri-tert-butyl Arylamine Zinc Phthalocyanine Derivatives as p-type Self-assembled Molecules for Efficient Perovskite Solar Cells

Abstract

Self-assembled monolayers (SAMs) offer a promising alternative to conventional charge-selective contacts in perovskite solar cells by effectively tuning the interface to enhance device performance. This work presents the development of phthalocyanine-based self-assembled monolayers (SAMs) designed for hole-selective contacts in inverted perovskite solar cells (iPSCs). These SAMs, ZnPc-1 and ZnPc-2, incorporate tri-tert-butyl groups to prevent aggregation, methoxy arylamine substituents to enhance hole mobility, and one or two carboxylic acid anchoring groups. We investigated the influence of these anchoring groups on device performance demonstrating that ZnPc-1 and ZnPc-2 function as efficient hole transport materials, achieving power conversion efficiencies (PCEs) of 14.92% and 14.06%, respectively—significantly outperforming the reference device (No HTM, 8.65%), being currently the record of Pcs SAMS in iPSCs. The enhanced performance is attributed to improved charge extraction and reduced hysteresis, minimising charge accumulation at the interface. These findings contribute to advancing high-efficiency iPSCs and offer valuable insights into developing next-generation phthalocyanine-based SAMs.