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In the present paper, we discuss the synthesis route dependence of luminescence in Li6M(BO3)3:Eu3+ (M = Y, Gd) phosphors. The current phosphors were prepared by two distinct methods of synthesis, viz., combustion and wet chemical methods for varying concentration of Eu3+ activator and the prepared phosphors were compared with those prepared by solid state reaction method. The phosphors were effectively synthesized by combustion and wet chemical methods in an open atmosphere. Each phosphor, thus, derived was further characterized for phase purity, morphology, and luminescent properties at room temperature. The emission and excitation spectra were pursued to discover the luminescence traits. The excitation spectra indicate that the prepared phosphors can be efficiently excited at 395 nm, 467 and 540 nm/550 nm light to give emission at 595 and 614 nm due to 5D0 → 7Fj transition of Eu3+ ions. A strong and dominant red emission is achieved at 614 nm achieved from the 5D0 → 7F2 transition of Eu3+ ions. Li6M1-x(BO3)3:Eux may be a suitable red-emitting component for solid state lighting.

Phototherapy is the use of light in the treatment of skin diseases that show improvement upon exposure to natural sunlight or man-made lamps. Artificial phototherapy treatments like Narrow band UVB (NB-UVB) phototherapy, Photochemotherapy by UVA (PUVA) and Targeted phototherapy are safe and widely used for several skin diseases like psoriasis, vitiligo, acne vulgaris, mycosis fungoides etc. Photodynamic therapy (PDT), a specialized phototherapy involves use of efficient photo sensitizers and optical radiations for the treatment of cancer and various other medical maladies. Efficacy of these treatments depends on proper selection of a phototherapy lamp which is decided by the wavelength of light emitted by the luminescent material present in it. These luminescent materials on account of their unique luminescence features of portability, power efficiency, lesser heat generation and durability find widespread application in bioassay and therapy. Here, we have discussed about the potential of various luminescent materials for phototherapy on the basis of their photoluminescence behaviour and also tabulated their application for various dermatoses. A few more luminescent materials are discussed in view of current developments in phototherapy and bioscience.

Li6Gd(BO3)3 phosphor doped with varying concentrations of europium was synthesized using a solid-state reaction route. Powder X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy methods were used to characterize the prepared phosphor. Photoluminescence excitation spectra of the Li6Gd(BO3)3:Eu3+ phosphors exhibited bands due to both Eu3+ and Gd3+ ions. Upon excitation of the host at 275 nm, the energy absorbed by Gd3+ ions can be transferred to Eu3+ ions in the Li6Gd(BO3)3 luminescent materials. The optimum concentration of Eu3+ ions for maximum luminescence yield was evaluated for the system. Color coordinates of prepared compound were calculated and plotted on the CIE diagram. The fluorescence lifetime of Eu3+ ions was found to be 2.12 ms. TL properties of the phosphor showed dominant peak at around 231 °C in addition to small shoulders at 131 and 367 °C. Various trap parameters and the kinetics for the glow peak were evaluated using the Chen’s peak shape method.

In this study, Li6 Y1-x Eux (BO3 )3 phosphor was successfully synthesized using a modified solid-state diffusion method. The Eu(3+) ion concentration was varied at 0.05, 0.1, 0.2, 0.5 and 1 mol%. The phosphor was characterized for phase purity, morphology, luminescent properties and molecular transmission at room temperature. The XRD pattern suggests a result closely matching the standard JCPDS file (#80-0843). The emission and excitation spectra were followed to discover the luminescence traits. The excitation spectra indicate that the current phosphor can be efficiently excited at 395 nm and at 466 nm (blue light) to give emission at 595 and 614 nm due to the (5) D0 → (7) Fj transition of Eu(3+) ions. Concentration quenching was observed at 0.5 mol% Eu(3+) in the Li6 Y1-x Eux (BO3 )3 host lattice. Strong red emission with CIE chromaticity coordinates of phosphor is x = 0.63 and y = 0.36 achieved with dominant red emission at 614 nm the (5) D0 → (7) F2 electric dipole transition of Eu(3+) ions. The novel Li6 Y1-x Eux (BO3 )3 phosphor may be a suitable red-emitting component for solid-state lighting using double-excited wavelengths, i.e. near-UV at 395 nm and blue light at 466 nm. Copyright © 2015 John Wiley & Sons, Ltd.

In this study, Li6 Y1-x Eux (BO3 )3 phosphor was successfully synthesized using a modified solid-state diffusion method. The Eu(3+) ion concentration was varied at 0.05, 0.1, 0.2, 0.5 and 1 mol%. The phosphor was characterized for phase purity, morphology, luminescent properties and molecular transmission at room temperature. The XRD pattern suggests a result closely matching the standard JCPDS file (#80-0843). The emission and excitation spectra were followed to discover the luminescence traits. The excitation spectra indicate that the current phosphor can be efficiently excited at 395 nm and at 466 nm (blue light) to give emission at 595 and 614 nm due to the (5) D0 → (7) Fj transition of Eu(3+) ions. Concentration quenching was observed at 0.5 mol% Eu(3+) in the Li6 Y1-x Eux (BO3 )3 host lattice. Strong red emission with CIE chromaticity coordinates of phosphor is x = 0.63 and y = 0.36 achieved with dominant red emission at 614 nm the (5) D0 → (7) F2 electric dipole transition of Eu(3+) ions. The novel Li6 Y1-x Eux (BO3 )3 phosphor may be a suitable red-emitting component for solid-state lighting using double-excited wavelengths, i.e. near-UV at 395 nm and blue light at 466 nm. Copyright © 2015 John WileySons, Ltd.