A Multifunctional Tyrosine‐Immobilized PAH Molecule as a Universal Cathode Interlayer Enables High‐Efficiency Inverted Polymer Solar Cells

Abstract Among the various biological components in the photosynthesis reaction, tyrosine (Tyr) is considered crucial for facilitation of charge/proton transfer. However, the practical realization of this capability in recent artificial solar‐energy conversion systems is limited by the required alignment of Tyr molecules with both host materials and themselves. In this work, Tyr−perylene diimide−Tyr (PDI‐Y) is designed for implementation of a molecular‐based artificial photosystem II, where PDI and Tyr act as an antenna and internal mediator, respectively. The experimental and theoretical investigations prove that the presence of covalently immobilized Tyr can enhance the intramolecular charge separation, leading to a significant reduction of the exciton recombination probability. To explore the feasibility of using Tyr‐immobilized PDI in practical applications, PDI‐Y is applied as a universal cathode interlayer in an inverted polymer solar cell (iPSC). The result demonstrates potential multifunctional roles of PDI‐Y as a sub‐photosensitizer and electron transport layer, leading to a superior photovoltaic performance in both fullerene (PC₇₁BM) and nonfullerene (Y6) based iPSCs. Consequently, the simple yet efficient Tyr‐immobilization approach is expected to offer tremendous opportunities for the advancement of electronic and optoelectronic applications.