Li ₂ SrSiO ₄ :Ce ³⁺ , Pr ³⁺ Phosphor with Blue, Red, and Near‐Infrared Emissions Used for Plant Growth <scp>LED</scp>

Abstract

Ce 3+ /Pr 3+ codoped Li 2 SrSiO 4 ( LSS ) phosphors with blue, red, and near‐infrared ( NIR ) tri‐emission have been prepared via a high‐temperature solid‐state reaction method. Under the excitation of 200 to 400 nm near‐ultraviolet ( n ‐ UV ), the photoluminescence ( PL ) spectra of phosphors are composed of visible and NIR two parts. The former exhibits blue and red emission bands centered at around 428 nm from 5 d –4 f transition of Ce 3+ and 611 nm from 1 D 2 → 3 H 4 transition of Pr 3+ , those overlap with photosynthesis action spectra of plants and absorption spectra of chlorophylls and carotenoids. While the later presents a broad NIR emission band peaking near 1039 nm caused by the 1 G 4 → 3 H 4 of Pr 3+ , matching with the absorption of bacteriochlorophyll. Their emission intensity ratios (B: R: NIR ) could be tuned by altering the relative ratios of Ce 3+ and Pr 3+ concentration in the phosphors to meet the requirements of multifarious plants and bacteria. The efficient energy transfer from Ce 3+ to Pr 3+ takes place in the LSS host, which ascribed to an exchange interaction according to PL spectra and decay curves of phosphors. Results suggest that the present LSS : Ce 3+ , Pr 3+ phosphors have great potential applications in plant growth n ‐ UV LED .