Structural and spectroscopic investigation of an efficient and broadband NIR phosphor InBO3: Cr3+ and its application in NIR pc-LEDs

A broadband NIR phosphor Cr3+-doped InBO3 was successfully prepared and systematically investigated. XRD refinement result reveals that Cr3+ ions locate the octahedral InO6 site in the InBO3 host. Under low crystal field strength (Dq/B = 1.78), InBO3: Cr3+ phosphor exhibits a broadband NIR emission at 820 nm (QE = 46.3%, FWHM = 138 nm) and has a high emission thermal stability, i.e. T1/2 = ~150 °C. The pc-LED prototype using InBO3: Cr3+ phosphor shows a high NIR output power of 37.5 mW with high conversion efficiency of 10.42%. Thus, the efficient broadband NIR emission makes Cr3+-doped InBO3 a good candidate as converted phosphor for high-power broadband NIR sources emitting in the NIR-I region.