Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Radosław Lisiecki"

Effect of AlF3 and H3BO3 fluxes on the structure and optical properties of Ca-α-SiAlON:Eu2+ phosphor powders DOI:10.15199/28.2016.1.6

  The continuous increase in demand for electric power necessitates constant search for new energy-efficient and economical light sources. One of them are light-emitting diodes (LEDs), requiring further development of materials enabling generation of warm white light that could replace the conventional light sources used so far. Problems related to the use of white LEDs include relatively low efficiency and light quality. A material that is currently a subject of interest due to its optical properties is Eu2+ doped Ca-α-SiAlON. It is regarded as one of the materials that can potentially be used as a yellow phosphor in white LEDs. The broad emission spectrum of Ca-α-SiAlON:Eu2+, bearing similarities with YAG:Ce3+ emission, is characterized by an emission peak maximum located in the wavelength range of 570÷585 nm, which enables obtaining a high colour temperature of a white LED. This study investigates the effect of addition of 1÷5 wt % AlF3 and H3BO3 as fluxes on the optical properties of phosphors obtained at different temperature. The syntheses were conducted in the temperature range of 1450÷1650°C in an N2/CO atmosphere. On the basis of the examination of the powder phase composition (by XRD), morphology, and chemical composition in microareas (by SEM/EDS), and the comparison of the emission spectra of the Ca-α-SiAlON:Eu2+ powders with a different flux content, it was found that the addition of AlF3 had a positive effect on emission intensity and quality. Key words: phosphors, wLED, sialon, flux, optical properties.1. INTRODUCTION Practically since the invention of the light bulb by Thomas Alva Edison in 1879 and the replacement of the steam engine with the first electric engines in industrial applications, a continuous increase in electric power consumption has been observed. Even at that time Edison realized the significance of his invention and he initiated the establishment of the first public power plant in the world in[...]

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