Energy-level-dominated luminescence tuning of Mn2+-doped Cs3Cu2I5 perovskites for single-component white LEDs.

In current white-light-emitting diodes (WLEDs), broadband emission is typically achieved by mixing multiple luminescent components. However, challenges such as interfacial incompatibility and energy-level misalignment significantly limit device performance and industrial scalability. To address these limitations of issues, this study proposes an Mn²⁺-doped Cs₃Cu₂I₅ lead-free perovskite for luminescence regulation and successfully constructs a single-component WLED. Through a grinding-calcination process, Mn²⁺ is doped into the Cs₃Cu₂I₅ lattice, introducing additional energy levels and activating d-d transitions. This enables an energy-level-dominated transformation from single-band blue emission to dual-band blue-yellow emission. Based on this strategy, we fabricated a series of color-tunable LED devices. Among them, the optimized WLED exhibits Commission Internationale de l'Éclairage chromaticity coordinates of (0.28, 0.33) and a color rendering index of 64.2, demonstrating excellent operational stability. This work challenges the conventional perception that white-light emission requires multi-component synergy and offers a novel design strategy for future lead-free perovskite-based WLEDs. It also opens up new ways, to the best of our knowledge, for the development of environmentally friendly and energy-efficient lighting appliances.