Positional Isomer Engineering of Carbazole-Based Hole Transport Materials for Perovskite Solar Cells

Abstract

The development of hole transport materials (HTMs) is crucial for advancing the efficiency and long-term stability of perovskite solar cells (PSCs). To address the limitations of conventional Spiro-OMeTAD, such as its complex synthesis and high production cost, we designed two novel carbazole-based HTMs, TCBZ-36 and TCBZ-27, through engineering the substitution position of the tricarbazole core. 2,7substitution of TCBZ-27 was found significantly enhances hole mobility and conductivity while improving film morphology compared to its 3,6-substituted counterpart, TCBZ-36. These superior properties translate into outstanding device performance, achieving a champion power conversion efficiency (PCE) of 25.2% (V oc = 1.16 V, J sc = 26.2 mA cm -2 , FF = 83.5%) along with exceptional environmental stability. This study presents a cost effective molecular design strategy that can simultaneously enhance both efficiency and stability of perovskite photovoltaics devices.