Abstract
An evolutionary optimization process involving a genetic algorithm and combinatorial chemistry was employed in an attempt to develop titanate-based red phosphors suitable for use in tricolor white light-emitting diodes. An eight-cation oxide system, including (K,Li,Na)x(Y,Gd,La,Eu) yTizOδ, was screened in terms of luminescence efficiency. The use of a combination of a genetic algorithm and combinatorial chemistry enhanced the efficiency of searching, as it is applied to the screening of phosphors in a limited composition space. As a result, the optimum composition was determined to be (Na0.92Li 0.08)(Y0.8Gd0.2)-TiO4:Eu 3+, the reproducibility of which was achieved by the conventional solid-state reaction method. Using the (Na0.92Li0.08) (Y0.8Gd0.2)TiO4:Eu3+ phosphor and an InGaN chip, a red LED was realized, so that the applicability of this new phosphor to white LEDs was confirmed. The luminescence of this phosphor was 110% that of the well-known scheelite variant phosphor and 600% that of a commercially available Y2O2S:Eu3+ at an excitation of 400 nm.
Original language | English |
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Pages (from-to) | 1768-1772 |
Number of pages | 5 |
Journal | Chemistry of Materials |
Volume | 18 |
Issue number | 7 |
DOIs | |
State | Published - 4 Apr 2006 |