Site-selective occupation and charge compensation engineering of Ni2+ enables blue-light-excitable emission spanning NIR-II to NIR-III windows

Blue-light-excitable NIR-II/III emission. • Ni 2+ occupies ScO 6 octahedral sites. • Sc substitution enables 1570–1690 nm tuning. • Zr 4+ charge compensation boosts emission 5-fold. • NIR-LED for night-vision and bioimaging. Long-wavelength NIR luminescent materials provide essential support for optoelectronic devices, yet realizing blue-light-pumped broadband emission across the NIR-II/III windows remain challenging. Herein, we successfully synthesized a series of Sr 2 Ga 1- x Sc x SbO 6 :Ni 2+ phosphors with tunable emission from 1570 to 1690 nm under 435–465 nm excitation. Corroborating evidence from DFT calculations, XANES spectroscopy, and structural refinement consistently confirms that the doped Ni 2+ ions occupy Ga/ScO 6 octahedron rather than SbO 6 sites. Furthermore, the introduction of Zr 4+ as a charge compensator effectively mitigates lattice defects induced by aliovalent substitution, leading to a remarkable enhancement in luminescence intensity across the entire composition series. The NIR pc-LED fabricated by integrating the optimized Sr 2 ScSbO 6 :Ni 2+ , Zr 4+ phosphor with commercial GaN chip exhibits promising performance for applications in night-vision imaging and chemical composition analysis. This work proposes a lattice-site engineering strategy to achieve ultralong-wavelength NIR emission and optimize luminescence performance, thereby establishing a new design paradigm for next-generation NIR phosphors. Download: Download high-res image (160KB) Download: Download full-size image Ga-site crystal-field engineering enables broadband NIR emission (1570–1690 nm), while Zr 4+ defect compensation enhances luminescence intensity, offering a new design paradigm for blue-light-excited NIR-II/III phosphors.