Synergistic effects of push-pull resonance molecules on passivation and charge dynamics in perovskite solar cells

Abstract

Exploring multifunctional interfacial modifiers is an effective approach to addressing interface issues in perovskite solar cells (PSCs) and improving device performance and stability. While most interfacial modifiers focus on passivating defects at the interfaces, there has been limited investigation into the relationship between molecular design and interfacial charge dynamics. This work introduces resonance molecules with a push-pull effect for interfacial modification, allowing for synergistic regulation of passivation effects and charge dynamics. Specifically, FCz-PO, which includes an electron-withdrawing fluorine atom, exhibits superior passivation but poor molecular stacking and charge extraction. In contrast, MCz-PO, featuring an electron-donating methoxy group, provides effective passivation, well-ordered molecular packing, and efficient charge extraction and transport. Consequently, PSCs using MCz-PO achieve high power conversion efficiency (PCE) of 24.74% and excellent operational stability. This study suggests that resonance structures can be an effective molecular design strategy for developing interfacial modifiers with both strong passivation capabilities and well-regulated charge dynamics.