|
The rising demands for spectroscopy applications in the fields of information encryption, non-invasive detection and component analysis have attracted extensive attention to 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 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 (I423 K / 303 K = 76%). Furthermore, we reasonably constructed the energy transfer from the Cr3+ to Yb3+ ions and obtained YCHSA:0.08Cr3+,0.03Yb3+ phosphor, performance improvement with a broader NIR emission band (FWHM = 327 nm) as well as better thermal stability (up to I423 K / 303 K = 83%). The excellent performance of NIR pc-LED is crucial for the spectroscopy application. The optimal samples and 450 nm commercial blue chips are packaged into NIR pc-LEDs, and give 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 are demonstrated.
|