Rare-earth-free Sr(Ca)2Ga2GeO7 phosphors with Ca-substitution-induced red-shift emission, perfectly aligned for Chlorophyll's absorption

Rare-earth-free Sr(Ca) 2 Ga 2 GeO 7 phosphors exhibiting self-activated luminescence properties were synthesized by solid-state method. The incorporation of Ca in place of Sr resulted in a pronounced redshift in the emission spectrum , enabling a closer alignment with the absorption spectrum of chlorophyll. This advancement offers increased flexibility in designing blue LEDs optimized for diverse crop growth applications. The substitution of Ca allows the phosphor's PL spectrum to precisely align with the absorption spectrum of chlorophyll. • Sr(Ca) 2 Ga 2 GeO 7 phosphors were synthesized by solid-state method. • This rare-earth-free phosphor exhibits self-activated photoluminescence. • The PL spectra of the phosphor can be modulated through Ca incorporation. • After modulation, the PL spectra match perfectly with the absorption spectra of chlorophyll a and b .