1) Fundamental luminescent materials
Visible emission from oxide phosphor materials Zn2Si04:Mn, Ga203:Eu and related compounds is being studied under electroluminescence, photoluminescence and cathodoluminescence. Thin films of these oxide phosphors are being grown by RF sputtering, on glass and ceramic substrates. Defects in II-VI phosphors are being studied to determine the relationship between point defects and luminescence in these materials.
This work shows for the first time that thin films of oxide phosphors can achieve bright EL emission using thin film dielectrics on smooth substrates.
Commercial brightness and efficiency values achieved on glass substrates with the new green phosphor achieved stable operation of Zn2Si0.5Ge0.5O4:Mn thin films paving the way for industrial use of these materials.
2) New luminescent devices
A new and unique type of luminescent “Sphere Supported Thin Film Electroluminescent” (SSTFEL) device has been developed. This involves spherical ceramic particles coated with a thin film semiconductor phosphor material, and then embedded in a polymer sheet.
Flexible light emitting sheets are enabled, which are capable of long life, high brightness performance. A photograph of a recent prototype is shown below:
3) New avalanche injection Devices
Two new research projects involve avalanche-injection electroluminescence. Here, electrons are injected into a semiconductor using high electric fields. High efficiency and low voltage EL devices suitable for flexible display devices may be realized by this research. Two PhD student projects on this are being started.
4/ Optical Fiber Liquid Crystal Display Technology:
A new type of display using the combination of a uniquely woven optical fiber array, light emitting diodes, and liquid crystal-based light modulation achieves an intense full colour display suitable for public information in the form of an electronic poster. New optical components are being developed to optimize the performance of this system.