Super Broadband Emission Across NIR‐I and NIR‐II Under Blue Light Excitation of Cr3+, Ni2+ Co‐Doped Sr2GaTaO6 Phosphor Achieved by Two‐Site Occupation and Effective Energy Transfer

Abstract

AbstractThe performance of the near‐infrared phosphor‐converted light‐emitting diodes (NIR pc‐LEDs) mainly depends on the NIR emitting phosphors used. Cr3+ doped materials can be excited by blue light chips, but their emission is located in the NIR‐I region (650–1000 nm). Ni2+ doped materials are mainly located in the NIR‐II region (1000–1700 nm), but they cannot be effectively excited by blue light chips. Herein, Cr3+, Ni2+ mono‐doped, and co‐doped Sr2GaTaO6 NIR emitting phosphors are prepared and investigated. Cr3+ and Ni2+ ions occupy two octahedral sites of Ga3+ and Ta5+. The co‐doping of Cr3+ ions has achieved two breakthroughs. One is to shift the optimal excitation wavelength from violet light to blue light due to the energy transfer (efficiency up to 70%) from Cr3+ to Ni2+. The other is to achieve the broadband and continuous emission across NIR‐I and NIR‐II regions (650–1700 nm, with a full width at half maximum (FWHM) of 410 nm (173 nm + 237 nm)). The prepared Sr2GaTaO6: 0.02Cr3+, 0.01Ni2+ phosphor is combined with a commercial 460 nm blue chip to realize its application in organic compounds identification, night vision, and biological imaging. This work points out a direction for the future development of efficient super broadband NIR‐emitting phosphors.