Eu² + -activated fluoride phosphors for narrowband UVA1 phototherapy LEDs

UVA1 phototherapy has been recognised for its therapeutic benefits. A narrow-band UV source should prove more effective for phototherapy. In this work, we describe the fabrication of a narrow-band UVA1 LED based on a commercially available 275 nm UVB chip and a KMgF3:Eu2+ or K2LiAlF6:Eu2+ phosphor. The fabricated LED shows line emission with a maximum at 358 nm and a compressed width of 5 nm, whereas the emission from an LED available in the market (Roithner, xsl-360-se) extends over a relatively wide range with a full width at half maximum of about 15 nm. Such sources have the potential to revolutionise UVA1 therapy.