-Research-

Development of Optically Functionalized Materials Based on Electronic Structure and Local Coordination!!

There are many luminescent materials and devices around us such as white LED lighting, laser projectors, TV and smartphone displays. These luminescent devices include inorganic phosphors with luminescence center (rare earth and transition metal ions). The optical properties of the phosphors vary greatly depending on the type of luminescence center, its geometrical and chemical coordination environment, and the electronic structure of the host material. Our research group investigate the factors to determine the optical properties and design new optical functional materials.

Generation of while light!

White LEDs and laser-excited white light sources consist of blue LED (or laser) and visible phosphors. Recently, green and red phosphors with a narrow luminescence band width for display application and non-quenching phosphors by high power laser excitation are studied. Through the elucidation of physical phenomena, we strategically create phosphors with higher properties.

Storage of light energy!

Persistent phosphors can show contentious luminescence even after stopping excitation source. We design persistent phosphors by controlling the photoinduced electron transfer process based on the electronic structures of inorganic compound with luminescence ions.

Sensor　using luminescence!

The luminescence properties vary by temperature and pressure. Thus, the phosphors can be used as optical thermometers and pressure sensors.

Persistent phosphors
tragged by magnet

By controlling the host composition, luminescence ions and carrier trapping ions, the white persistent phosphor dragged by magnet were successfully developed.

Quantum Dots

Quantum dots have a great deal of attentions because of the strong absorption and luminescnece.　　However, many of quantum dots incluede toxic ions. Thus, we are trying to preapre non-toxic quantum dots.

Other research topics

Wavelength converter for solar cells, Pigments, Photochromism, luminescence quenching, Mechano-luminescence, pressure induced phase transition.