Structure-modulation-enhanced multi-emission luminescence in Sb3+/Er3+ co-doped double perovskites for single-component white/NIR LEDs and dual-mode thermometry

Lead-free double perovskites (DPs) are emerging as sustainable luminescent materials owing to their low-cost synthesis, low toxicity, and superior stability. However, their practical applications are impeded by low luminescence efficiency and a single emission center. To overcome these challenges, we reported a structure-modulation strategy to develop Sb/Er: Cs 2 Na 0 . 95 Ag 0 . 05 YbCl 6 (Sb/Er: CNAYC) DPs by co-doping Cs 2 NaYbCl 6 with Sb 3+ /Er 3+ ions and substituting Na + with Ag  +  ions. The Sb 3+ /Er 3+ co-doping can introduce multiple emission centers from visible to near-infrared (NIR). Meanwhile, the Na + -Ag + alloying-induced lattice distortion not only enhances the photoluminescence efficiency by breaking the parity-forbidden transitions, but also enables the color of emission to be tuned to the white light range. The Sb/Er: CNAYC DPs simultaneously deliver efficient blue (460 nm@Sb 3+ ), green/red (552/667 nm@ Er 3+ ) and NIR (980/1540 nm@Yb 3+ /Er 3+ ) emissions, providing a promising luminescent material for single-component white/NIR LEDs. Furthermore, the Sb/Er: CNAYC DPs also display pronounced temperature-sensitive fluorescence intensity ratio (FIR) and lifetime characteristics, enabling them well-suited for dual-mode temperature sensing. This study is expected to establish a universal lattice-modulation strategy that yields single-component luminescent materials exhibiting both high-efficiency white/NIR emission and accurate multimode thermometry for next-generation optoelectronic applications.