Cu2+ and Cr3+ doped borate glasses and glass-ceramics as light conversion materials for plant photosynthesis

We present a kind of Cu2+/Cr3+ doped borate luminescence glasses and glass-ceramics for potential indoor plant cultivation applications. These materials were prepared using a melt-quenching route and their luminescent and structural properties were investigated. The Cu2+ in the as-obtained materials can generate blue emission under ultraviolet (UV) excitations. The Cr3+ ions doped glasses and glass-ceramics display two intense broadband absorptions located in the UV and green light regions, also exhibit the sharp-line 2E2→4A2 emission and the broadband 4T2→4A2 luminescence. These emissions originating from Cu2+ and Cr3+ have blue (peaking at ∼480 nm) and far-red-emitting components (∼690–780 nm), which play a promising role in regulating the photomorphogenesis of plants. For certain base glass compositions, the crystals ZrO2 were spontaneously precipitated during the melt quenching process and the glass-ceramics were obtained accordingly. The relative emission intensity, position of emission bands, and fluorescence decay kinetics of Cu/Cr doped borate glasses and glass-ceramics can be effectively modulated via a compositional design engineering and the variation of excitation wavelength. The excellent photoluminescence features make these glasses and glass-ceramics very promising for applications in plant growth light-emitting diodes (LEDs).