Toshiba Develops Transparent Photoluminescent Phosphor for LED

Toshiba Corporationhas unveiled a technology breakthrough in photoluminescence, a novel phosphor that delivers excellent solubility in polymers or organic solvents, where it is transparent and colorless under visible light, and that emits persistent red-light emissions under UV light, with excellent color purity and a luminescence six times that of current phosphors. These characteristics open up many potential applications in areas that include LED lighting, displays, deep UV sensing, security printing, and pesticide residue testing.

A phosphor is a substance that absorbs energy from a light source, such as UV or visible light, and releases that energy by emitting colored light. Phosphors are commonly used in LED lighting and displays, and in security printing. However, in the field of mini- and micro-LED lighting and displays, where the chips used are very small, the inorganic phosphors typically used have a limited color reproduction capability and luminescence intensity. These phosphors are also insoluble and exist as fine particles, and when used in security printing, printed patterns become faintly visible, depending on the angle of view and light exposure. Toshiba’s new phosphor overcomes these problems.

Toshiba has focused its photoluminescence research on novel lanthanide luminescent complexes. The company has developed a proprietary molecular design method, and used this to bind the ions of a standard Eu(III) luminescent complex with two or more phosphine oxide structures, including a branched tetraphosphine tetraoxide ligand recently discovered by Toshiba.