Enhanced broadband NIR luminescence of novel garnet-type Lu3Mg2GaSi2O12:Cr3+ phosphors with different fluxes

The swift progress in portable spectrometer technology has fostered a widespread need for compact light sources. Concurrently, near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs), characterized by their low cost and compact structure, emerge as an optimal choice. Inspired by phase optimization through fluxes, we successfully synthesized pure phase Lu 3 Mg 2 GaSi 2 O 12 (LMGS):Cr 3+ , 3 wt%MgF 2 luminescent materials by incorporating various fluxes including LiF, NaF, MgF 2 , CaF 2 , SrF 2 and BaF 2 . These materials emit broadband NIR light ranging from 620 nm to 1150 nm, with full width at half-maximums (FWHMs) exceeding 125 nm. By employing a dual-fluxes strategy to further enhance the luminescence intensity of Cr 3+ , the LMGS:3%Cr 3+ , 1 wt%NaF, 2 wt%MgF 2 sample exhibits a 2.45 times increase in emission intensity compared to the LMGS:3%Cr 3+ , 3 wt%MgF 2 sample. Concurrently, the quantum efficiency rises from 24 % to 46 %. Moreover, the integrated emission intensity of LMGS:3%Cr 3+ , 1 wt%NaF, 2 wt%MgF 2 retains at 75 %@425 K of its value at RT. Upon coupled with a 430 nm LED chip, the luminescent material exhibits an NIR output power of 43.8 mW@300 mA, indicating promising applications in rapid night identification, night vision and non-destructive testing.