Efficient and Stable Pure-Blue Perovskite Light-Emitting Diodes for High-Color-Purity Advanced Displays

Metal halide perovskite light-emitting diodes (PeLEDs) have garnered substantial attention owing to their exceptional optoelectronic properties, enabling rapid advancements in red and green devices with external quantum efficiencies (EQEs) approaching 30%. However, blue PeLEDs continue to lag behind in both efficiency and spectral stability, posing a critical barrier to achieving full-color, ultrahigh-definition displays. Although sky-blue PeLEDs (470–490 nm) have demonstrated relatively high efficiencies, their emission spectra have failed to meet the stringent chromaticity requirements defined by Rec.2020 and NTSC standards. Deep-blue emitters (440–460 nm), however, raise safety concerns owing to potential photobiological hazards, such as retinal damage. These limitations underscore the urgent need for pure-blue PeLEDs (460–470 nm) that offer an optimal balance between spectral accuracy, device safety, and performance. In this paper, we explore strategies aimed at improving the spectral stability and emission efficiency of pure-blue PeLEDs. Specifically, we highlight the impact of dimensional engineering and ion substitution on enhancing spectral stability and discuss additive engineering, ligand engineering, and interface engineering as key approaches for boosting emission efficiency. Together, these strategies offer a comprehensive framework for addressing the critical limitations of pure-blue PeLEDs and advancing their integration into next-generation display technologies.