Introducing Jahn-Teller distortion to enhance the practicability of (Ga,Sc)2O3:Cr3+ near-infrared phosphor

Herein, we report a series of tunable and highly efficient Ga1.594-2xSc0.4MgxGexO3:0.006Cr3+ phosphors via regulating the crystal field environment in (Ga,Sc)2O3:Cr3+ system. This material exhibits a gradual red-shift of the emission spectra from 784 to 814 nm, and a spectral broadening with FWHM increased from 138 nm to 169 nm as the increase of x value. However, the position of excitation peak has almost no variations in the blue light region, enabling it to be perfectly matched with blue LED chip. Upon 450 nm excitation, the IQE remains above 90% when x ≤ 0.08 (784 ≤λem ≤ 803 nm); while the thermal stability decreases as the increase of x in the whole range. Finally, a prototype NIR pc-LED was fabricated via combining Ga1.354Sc0.4Mg0.12Ge0.12O3:Cr3+ phosphor with 450 nm blue LED chip, which shows an excellent NIR output power of 26.91 mW with high photoelectronic conversion efficiency of 9.70% under a driving current of 100 mA. Thus, this work provided a series of efficient NIR phosphors through local structure regulation, which may have great potential for spectroscopy application. •A series of tunable (784 ≤λem ≤ 814 nm) broadband NIR Ga1.6-2xSc0.4MgxGexO3:Cr3+ phosphors were synthesized.•A spectral broadening with FWHM increased from 138 nm to 169 nm can be achieved.•The IQE remains above 90% when 784 ≤λem ≤ 803 nm.