Electron-deficient intermolecular adhesives: a new class of multifunctional interlayers for efficient and stable perovskite solar cells

Abstract

Since 2009, perovskite solar cells (PSCs) have advanced significantly, achieving over 26% efficiency for single-junction devices and exceeding 34% for silicon-perovskite tandem cells. Despite these successes, the weak adhesion of C60 to perovskite layers, due to van der Waals interactions, hinders long-term stability. In this study, we introduce electron-deficient intermolecular adhesives (EDIAs) as a novel interlayer material to enhance adhesion between perovskite and C60 layers. Comprehensive analyses, including density functional theory calculations, microscopy, and spectroscopy, demonstrate that EDIAs, particularly NDI-C9-Ace comprising of three key functionalities: a π-electron-deficient arene core, a hydrophobic passivation core, and a secondary-bond anchoring core, significantly improve bonding strength and recombination passivation. This leads to enhanced efficiency as well as enhanced mechanical and photochemical stability in PSCs. Long-term stability tests further confirm the superior durability of EDIA-enhanced devices. This study highlights EDIA as a promising strategy for enhancing the robustness and efficiency of PSCs. © 2025 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences