The Commission of the grant agency VEGA for machinery engineering, information and communication technologies and materials science evaluated the research projects, which have ended in 2017. The project 1/0631/14 entitled New inorganic rare earth based phosphors emitting white light for applications in LEDs, led by dr. Robert Klement was selected by the commission as the project, which achieved excellent results. The project was also selected as one the research highlights, which will be published at the VEGA website.
The project team worked on development of glass-polycrystalline phosphors doped with Ce3+-Mn2+/Mn4+ a Eu2+/Eu3+ in chemically stabile matrices that emit white light with enhanced emission in red spectral range under NUV excitation. The controlled crystallization of glasses enables preparation of systems emitting the white light under NUV excitation (Ce3+ in YAG matrix yellow-green emission, Ce3+ in residual glass blue emission). Very promising results have been achieved for Y2O3-Al2O3 system doped with Eu2+/Eu3+ ions. Due to the presence of both Eu oxidation states in host matrix, white light emission was achieved, and by tuning of excitation wavelength the intensity of red light portion in the emitted white light can be effectively increased. Undoubted benefit is that the prepared phosphors contain only one RE ion at low concentration in the host matrix compared to known phosphors in which for white light emission the presence of 2-3 RE ions in one or several phases is essential.
Congratulations to dr. Klement and his team.