Polymer Network Modified Perovskite for High-Performance Pure Blue Light-Emitting Diodes

Abstract

Achieving highly efficient and spectrally stable pure-blue perovskite emission remains the most critical outstanding challenge for completing the full-color implementation and commercialization of perovskite-based display technologies. Pure blue perovskites inherently suffer from chloride vacancy defects, crystallization-induced morphological disorder, interfacial lattice strain, and pronounced halide ion migration, all of which collectively limit their radiative efficiency and spectral stability. Here, we introduce a polymer network wrapping strategy using poly(4-vinylphenol) (PVPh) that provides an integrated solution to these tightly coupled limitations. The PVPh network forms dual-site interactions with the perovskite surface, increasing halide vacancy formation energies and suppressing deep trap states; regulates crystallization to form dense, pinhole-free films; mechanically relaxes interfacial lattice strain; and confines halide migration under electrical bias. Supported by combined DFT calculations, structural analyses, and device-level diagnostics, this multifunctional approach directly addresses the intrinsic instability pathways of pure-blue perovskites. As a result, the optimized PeLEDs deliver a record-high external quantum efficiency of 9.82%, a maximum luminance of 1544 cd m- 2 at 467 nm, representing the highest performance reported for 3D-based pure-blue PeLEDs to date. This work establishes a simple, solution-process-compatible material design framework for stabilizing wide-bandgap perovskites and offers a promising pathway toward commercially viable pure-blue display technologies.