摘要： Red/Near-infrared (NIR) emitting Mg1-xZnxAl1.98Cr0.02O4 nanoparticles were synthesized by co-precipitation followed by firing(1200°C). Gradual shift of XRD peaks with Zn-content confirmed complete solid-solution formation. HRTEM revealed hexagonal sheet-like structures and lattice fringes revealed their single-crystallinity. Owing to refractory nature of MgAl2O4, particles were smaller(~38nm) in Mg-rich samples and gradually increased(~58nm) with Zn-substitution. Due to trigonal distortion, the fine splitting of the 4T1g level of Cr3+ manifests as asymmetric band(400nm) in the excitation spectrum. Cr3+ emission was clearly observed, comprising of R-line and multi-phonon side-bands on either side, with maximum R-line intensity for x=0.5. With increasing x, side-bands were more pronounced probably due to the band-gap difference of end members. High Dq/B(3.5-3.9), suggested Cr3+ in a strong crystal-field. Racah-parameter(B) variations suggest increased electron delocalization over molecular orbitals for higher Mg2+ substitutions. Longer lifetimes(23-34ms) are well-suited for bioimaging and optoelectronic applications. Such a simple synthesis can be easily extended to other important phosphors.