A Ce3 +-activated germanate blue phosphor for indoor plant lighting and temperature sensing

Indoor plant cultivation requires artificial light sources with broadband blue emission (400–500 nm) to match chlorophyll absorption spectra , yet most phosphors exhibit narrow emission bands. Meanwhile, non-contact optical thermometers face limitations in sensitivity (<1.5 %·K −1 ), hindering precise temperature monitoring. Here, we report a Ce 3+ -activated Sr₂Ga₂GeO₇ (SGGO) phosphor that simultaneously addresses these challenges. Its broad blue emission ( full width at half maximum , FWHM = 74 nm) fully overlaps with chlorophyll a and b absorption, while its temperature-dependent luminescence achieves a record relative sensitivity of 1.62 %·K −1 . The phosphor was synthesized via a high-temperature solid-state method, with Ce 3+ substituting Sr 2+ sites confirmed by Rietveld refinement . Concentration quenching analysis revealed dipole-dipole interactions as the dominant mechanism. This work demonstrates a dual-functional material that bridges the spectral gap for plant growth lighting while demonstrating promising performance in high-sensitivity optical thermometry, advancing smart agricultural technologies.