Nano-monolayer NiPS ₃ crystal inducing reinforced polymeric π-orbital coherent stack for 20.83% efficiency organic photovoltaics

In organic photovoltaics (OPVs), the π-orbital coherent stack of π-conjugated polymers in the active layer exerts a profound influence on exciton dissociation and charge transport. Nevertheless, the structural flexibility intrinsic of π-conjugated polymers fundamentally restricts ordered π-orbital coherent stack, thereby establishing persistent performance limitations in OPVs. Here, we demonstrate a universal crystal-induced polymeric π-orbital coherent stack reinforcement strategy by incorporating nano-monolayer nickel phosphorus trisulfide (NiPS₃) crystal as a multifunctional additive, to modulates tighter π-π stacking and extended crystallite coherence length. These structural improvements synergistically extend exciton lifetime, suppress carrier recombination, and optimize charge transport. Consequently, OPVs based on D18-Cl:L8-BO system achieves an impressive power conversion efficiency (PCE) of 20.83% with concurrent improvements in short-circuit current density and fill factor. The universality of this approach is further confirmed in PM6:L8-BO (PCE boosts from 17.41±0.21 % to 18.08±0.11 %) and D18:L8-BO (PCE improves from 19.20±0.27 % to 20.19±0.20 %) systems, where nano-monolayer NiPS₃ crystal universally mediates the formation of tightly π-orbital coherent stack of π-conjugated polymers with enhanced crystallite coherence length. This work establishes nano-monolayer NiPS₃ crystal as powerful tools for modulates π-orbital coherent stack of conjugated polymers, offering a materials-agnostic pathway toward high-efficiency OPVs.