Eu2+-doped ultra-broadband VIS-NIR emitting phosphor

Abstract

The discovery of ultra-broadband VIS-NIR emission phosphors is a major challenge for miniature/portable devices in special applications like bio-sensing. In different solid materials, the Eu2+ emission band usually covers the blue to red spectral region. The near infrared spectral range is extremely difficult to obtain with the activator Eu2+, even in nitride host materials. In this work, we design and report a record-breaking oxide-based phosphor, Ba3ScB3O9:Eu2+, which yields VIS-NIR light (510–1100 nm) in response to ultraviolet-blue light excitation. Under a preferred excitation at 376 nm, Ba3ScB3O9:Eu2+ shows a broadband long-wavelength emission with the main peak, full width at half maximum and Stokes shift of 735 nm, 205 nm and 12991 cm−1, respectively. The spectral position and band width can be rationalized by combining the nephelauxetic effect and crystal field. By covering the title phosphor on a blue LED chip (450 nm), a VIS-NIR pc-LED containing Eu2+ emission with NIR out power of 2.3 mW@100 mA and photoelectric efficiency of 9.3%@100 mA is obtained. According to ultra-broadband emission in visible-near infrared region, application in LEDs for real-time non-destructive examination occurs promising.