Twisted Nanoribbon‐Like Electron Acceptor With Suppressed Non‐Radiative Loss and Seed‐Assisted Crystallization for High‐Efficiency Organic Solar Cells

Abstract

ABSTRACT While large π‐conjugated nanoribbons possess highly tunable electronic properties, their potential in high‐performance organic photovoltaics (OPVs) remains largely untapped. Herein, we report a π‐extended nanoribbon‐like electron acceptor, PDIY, featuring a molecular length of 4.85 nm (11 fused rings) and near‐infrared absorption extending to 900 nm. PDIY is engineered with a perylene diimide core fused to dual rylene units and end‐capped with Y‐type acceptor moieties. The rigid conjugated framework effectively suppresses conformational/vibronic relaxation, weakens electron‐phonon coupling, and yields an intrinsically low non‐radiative voltage loss (Δ V nr ) of 0.146 eV, among the lowest values reported to date, thereby enabling higher open‐circuit voltage. Despite its large size, the twisted geometry of PDIY leads to a unique “low crystallinity, strong aggregation” behavior. This allows PDIY to serve as a potent morphology‐directing additive that acts in a manner consistent with heterogeneous nucleation, inducing the formation of robust, large‐diameter fibrillar networks within bulk‐heterojunction blends. Consequently, the integration of PDIY yields a simultaneous enhancement across all photovoltaic parameters, boosting power conversion efficiencies (PCEs) from 19.62% to 20.57%. This work establishes twisted nanoribbon‐like acceptor as a versatile molecular platform for the dual regulation of excited‐state dynamics and active‐layer morphology in next‐generation OSCs.