Ultra-broadband near-infrared Gd3MgScGa2SiO12: Cr, Yb phosphors: Photoluminescence properties and LED applications

Developing novel broadband near-infrared (NIR) phosphors is crucial to promote NIR phosphor-converted light emitting diodes (pc-LEDs) development. In this work, a new ultra-broadband NIR phosphor Gd3MgScGa2SiO12: Cr3+ (GMSGS) was achieved by replacing Sc3+-Ga3+ in Gd3Sc2Ga3O12 with Mg2+-Si4+. Under the excitation of blue light, the peak emission wavelength of GMSGS: 0.04Cr3+ is about 820 nm with a full width at half maximum (FWHM) of ∼180 nm and an internal quantum efficiency (IQE) of 50 %. Benefited from the superposition of Cr3+ emission and highly efficient Yb3+ emission excited by energy transfer (ET) from Cr3+, the codoped GMSGS: 0.04Cr3+, 0.007Yb3+ phosphor shows an ultra-broadband of 300 nm. Moreover, Yb3+-codoping improves the thermal stability due to the ET from Cr3+ to more thermally stable Yb3+ emitters, and the integrated intensity of GMSGS: 0.04Cr3+, 0.007Yb3+ at 400 K was 63 % of that at room temperature. The packaging results exhibit that ~20 mW output power was achieved at 100 mA input current, which suggests promising potential of GMSGS: Cr3+, Yb3+ phosphor in NIR pc-LED applications.