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Information × Registration Number 0219U005652, 0119U001605 , R & D reports Title Highly-efficient red-emitting phosphors based on non-rare earth multicomponent oxides popup.stage_title Head Borkovska Lyudmyla, Registration Date 27-12-2019 Organization Institute of Semiconductor Physics popup.description2 The research objects are the powders and ceramics of manganese doped magnesium ortho- and metatitanates, produced by high temperature solid state reaction method. The aims of the work are the development of effective inexpensive environmentally friendly multicomponent red phosphors based on activated by Mn4+ ions magnesium ortho- and metatitanates for illumination application and development of the methods for control of localization and charge state of Mn ions in the crystal lattice of magnesium ortho- and metatitanates. Research methods are the photoluminescence, x-ray diffraction, electron paramagnetic resonance, diffuse reflectance, scanning electron microscopy, energy dispersive X-ray spectroscopy. Multicomponent manganese doped red phosphors based on magnesium ortho- and metatitanates, Mg2TiO4 and MgTiO3,were produced by the high-temperature solid-state reaction for applications in white LEDs. It is shown that Mn in Mg2TiO4 mainly has a charge state +4, Mn4 +, and the largest intensity of red luminescence band of Mn4+ ions peaked at 660 nm is observed at Mn concentrations of 0.1%. It is established that the main reasons of the low intensity of Mn4+ luminescence band in MgTiO3 peaked at 701 nm are the predominant incorporation of Mn in the charge state +2 and considerable thermal quenching of the luminescence intensity at room temperature. It is found that additional annealing of the Mg2TiO4:Mn phosphors in the flow of oxygen at 600 °С results in the increase of intensity of red luminescence in 1.6-1.8 times, and the annealing in the flow of nitrogen - to its decrease in 3-20 times. It is found that excess MgO in the initial charge allows to increase in 1.5-2 times the intensity of red luminescence of Mn4 + ions in Mg2TiO4:Mn phosphors and in 30-50 times in MgTiO3:Mn phosphors. It is proposed that the excess of MgO promotes the incorporation of Mn into titanium cite, Ti4+, and results in more uniform distribution of the impurity in the grain of magnesium titanate. Projected assumptions about the development of the research object are the improvement of the methods of fabrication of the phosphors based on manganese activated magnesium titanates with high intensity of red luminescence that can be used in white light-emitting diodes. Product Description popup.authors Ворона Ігор Петрович Корсунська Надія Овсіївна Стара Тетяна Русланівна popup.nrat_date 2020-04-02 Close