MTiTaO6: Cr3+ (M = Al3+, Ga3+, Sc3+) Phosphors with Ultra-Broadband Excitation Spectra and Enhanced Near-Infrared Emission for Solar Cells

Achieving ultra-broadband absorption and enhancing the near-infrared (NIR) emitting properties of NIR phosphors is a key challenge to realize its multiple applications, such as solar spectrum conversion, spectral analysis, and night vision. Here, a novel NIR phosphor system MTiTaO6: Cr3+ (M = Al3+, Ga3+, Sc3+), with an excitation spectrum as broad as 421 nm and enhanced NIR emission is reported. It is the widest excitation spectrum among the known Cr3+-doped NIR phosphors. Structural and spectroscopic analysis shows that the ultra-broadband excitation spectrum originates from the overlap of multiple luminescence centers. Additionally, the emission peak is red-shifted from 816 to 871 nm with increasing M ion radius, and the emission intensity is enhanced, which not only makes the emission spectra more compatible with the response curve of c-Si solar cells, but also gives it an advantage in NIR spectroscopy applications. Comparison of the excitation spectra with the solar spectrum and spectral analysis of the emission spectra of water and alcohol demonstrate its promising applications.