Simultaneous adjustment of afterglow wavelength and intensity in indium-substituted Ga1.99−xInxO3:0.01Cr3+

Near-infrared persistent luminescent nanoparticles (PLNPs) are widely used for deep tissue penetration in bio-imaging. Ga2O3:Cr3+, a promising phosphor material, has been extensively studied for its suitable band gap and tunable emission wavelength. Although a redshift in the fluorescence wavelength has been achieved, the persistent luminescence properties of Ga2O3:Cr3+ following this redshift have not been extensively explored. Herein, we have prepared Ga1.99−xInxO3:0.01Cr3+ (x = 0–1.99)(GIO) PLNPs utilizing a hydrothermal method followed by calcination. Replacing gallium with indium in the crystal structure of Ga2O3:Cr3+ redshifts the emission wavelength to 830 nm and induces persistent luminescence, which is attributed to lattice distortion caused by the substitution of gallium with indium, which modifies the crystal field around the Cr3+ ions. The as-prepared GIO nanoparticles show potential for future low-cost, deep-tissue bioimaging applications.