Configurable Static Dipole Field Drives Efficient Charge Extraction Across Nonconjugated Polymer Encapsulation Layers of Halide Perovskites for Advanced Photoelectrochemical Functions

ABSTRACT Harnessing the scalability and processing versatility of nonconjugated polymer encapsulation offers a compelling pathway toward the robust practical deployment of halide perovskites. However, its effective implementation in interface‐dependent optoelectronic and energy‐conversion processes remains constrained by the polymers’ insulating nature, which fundamentally impedes charge transport. Herein, a configurable static dipole field is introduced through rationally reconfiguring the polymer encapsulation layer into an asymmetrically charged bridging interface (ACBI) to enable efficient charge transfer across such polymer encapsulation. By designing a charge‐asymmetric poly(cation–anion) nanostructure positioned between the encapsulated perovskite and charge‐acceptor material, the ACBI generates interfacial dipoles that establish a controllable net electric field across the polymer encapsulation. Comprehensive theoretical and experimental analyses confirm the existence of this dipole field, whose intensity is readily tunable by structural configuration. Implemented in a PVP‐protected Cs 3 Bi 2 I 9 system, the optimized ACBI configuration with a strong dipole field significantly accelerates charge‐transfer dynamics (validated by transient absorption spectroscopy), greatly enhancing photoelectrochemical activity. Leveraging this mechanism, a dipole‐field‐mediated photoelectrochemical sensing strategy is demonstrated, achieving a detection limit as low as 0.52 pM for the endocrine disruptor di(2‐ethylhexyl) phthalate. This static dipole engineering converts insulating polymer encapsulants into charge‐transport pathways, unleashing the potential of polymer‐encapsulated perovskites for advanced optoelectronic applications.