New Synthesis of Novel Phosphor for LED Technology: Sr3B2O6:Eu2+ Using SrB4O7:Eu2+ as a Precursor

Phosphors, used in plasma screens, medical imaging, and LED lighting, are materials that absorb energy and emit light. A promising activator for use in phosphors is Europium2+. Depending on the host, this dopant can emit anywhere in the visible spectrum. According to the literature, it is difficult to dope Eu2+ into Sr3B2O6 due to the stability of Eu3+. The literature indicates that the phosphor SrB4O7 readily incorporates Eu2+ into its structure. This work describes an investigation of a new method of making Sr3B2O6:Eu that uses SrB4O7:Eu2+ as a precursor. If SrB4O7:Eu2+ is used as a starting material for Sr3B2O6:Eu, then there should be less Eu3+ and more Eu2+ in the resulting compound than when prepared by traditional methods. Samples of Sr3B2O6:Eu were prepared using traditional methods: grinding stoichiometric amounts of strontium carbonate (SrCO3), boric acid (H3BO4), and europium oxide (Eu2O3) and firing in a reducing atmosphere. Samples using the new method were prepared by grinding stoichiometric amounts of SrCO3, H3BO4 and Eu2O3 and firing in a reduction atmosphere to form SrB4O7:Eu2+. Stoichiometric amounts of SrCO3 were added, and samples were fired in a reducing atmosphere again. Samples prepared by the new method had a higher ratio of Eu2+ to Eu3+ emission than samples prepared by the traditional method. This method may be applied to other phosphors to incorporate Eu2+, such as Sr3Y2(BO3)4:Eu. This method may also lead to previously unmade novel phosphors