Lanthanide-free amorphous aluminum-borate micropowders: Broadband emitting phosphors for warm-white LED lighting
Résumé
We develop original phosphors based on glassy aluminum borate micropowders without any metal activator for the development of eco-efficient white-LEDs. Thus, these lanthanide-free phosphors allow producing intense photoluminescence broadbands in the whole visible range from carbon-related radicals trapped in glassy grains. The origin of emitting centers has been specified by coupling microcalorimetry, mass spectrometry, thermo- and afterglow-luminescence, NMR, EPR and pulsed ENDOR spectroscopies combined with DFT calculations. Thus, from only one phosphor excited with near-UV LED chips (365-390 nm), we can generate intense warm white light: internal quantum yields around 80-90% and high color rendering indexes (CRI = 92-94).