A single luminescence center ultra-broadband near-infrared LiScGeO4:Cr phosphor for biological tissue penetration

Abstract

In this work, in order to meet the application of near-infrared phosphor-converted light emitting diodes (pc-LEDs), an ultra-broadband emission phosphor, LiScGeO₄:Cr, was synthesized. Its FWHM reaches 335 nm, and its emission spectrum ranges from 800 nm to 1650 nm, which almost covers the entire near-infrared second window (NIR-II). The broadband emission is thought to be caused by the ⁴T₂ → ⁴A₂ transition of the Cr³⁺ ion. This transition occurs due to the olivine structure of the crystal, which causes the Cr³⁺ ions to inhabit a low-symmetric crystal field, and the crystal field strength is very weak. NIR pc-LEDs were fabricated by combining a 460 nm blue LED with this phosphor, which penetrates 4 cm thick beef. The results indicate that there may be a potential application for this phosphor in the field of biological tissue penetration and non-destructive testing.