A study of light-converting composites used in white light-emitting diodes

An experimental wedge method was suggested for obtaining ample information on the properties light-converting composites used in light-emitting diodes. The parameter determining the luminous emittance of the composite layer is the photoluminophore mass in it. It can be optimized experimentally using the suggested procedure. The composite based on Eu-doped Sialon luminophore upon excitation at a wavelength of 450 nm exhibits the optimal luminous emittance and emission color at a specific load of approximately 5 mg cm-2. With variation of the excitation wavelength in the interval 430-470 nm, the observed trends in the luminous emittance of the Sialon composites are preserved in a wide interval of concentrations and thicknesses of the composite layer. The luminous emittance varies in the same direction as the wavelength. © 2013 Pleiades Publishing, Ltd.