Highly efficient broadband NIR phosphor Y2CaHfScAl3O12:Cr3+,Yb3+ with superior thermal stability for spectroscopy applications

Abstract

The rising demand for spectroscopy applications in the fields of information encryption, non-invasive detection and component analysis has attracted extensive attention to achieve high power near-infrared (NIR) light sources. Near-infrared phosphor-converted light emitting diodes (NIR pc-LEDs) are regarded as ideal light sources to meet the current needs due to their advantages of high power, low cost, and portability. However, it remains a huge challenge to design a NIR phosphor with high emission efficiency, superior thermal stability, and broadband emission. Herein, a novel NIR phosphor, Y₂CaHfScAl₃O₁₂:Cr³⁺ (YCHSA:Cr³⁺), is reported from a fundamental study of garnet type inorganic materials. YCHSA:Cr³⁺ displays an intense broadband NIR emission covering from 650 to 900 nm with a full width at half maximum (FWHM) of 110 nm and good thermal stability (I_423K/303K = 76%). Furthermore, we reasonably utilized the energy transfer from the Cr³⁺ to Yb³⁺ ions and obtained the YCHSA:0.08Cr³⁺,0.03Yb³⁺ phosphor, and achieved performance improvement with a broader NIR emission band (FWHM = 327 nm) as well as better thermal stability (up to I_423K/303K = 83%). The excellent performance of NIR pc-LED is crucial for spectroscopy applications. The optimal samples and 450 nm commercial blue chips are packaged into NIR pc-LEDs, and give a high output power of 63.6 mW at a drive current of 100 mA. Finally, the superior performance in information encryption and non-invasive detection is demonstrated.