Potential of luminescent materials in phototherapy.

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.

Luminescence study of Eu(3+) doped Li6 Y(BO3 )3 phosphor for solid-state lighting.

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.