Title

New Synthesis of Novel Phosphor for LED Technology: Sr3Y2(BO3)4:Eu Using Sr3B2O6:Eu and SrB4O7:Eu Precursors

Presenter Information

Troy Kilburn
Zachary Way

Document Type

Oral Presentation

Location

SURC 137B

Start Date

16-5-2013

End Date

16-5-2013

Abstract

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 divalent europium (Eu2+). Depending on the host, this dopant can emit anywhere in the visible spectrum. However, in many host compounds, it is difficult to dope Eu2+ due to the stability of trivalent europium (Eu3+). The literature indicates that the phosphor SrB4O7 readily incorporates Eu2+ into its structure, but that Sr3B2O6 does not. Here, we show that we can increase the ratio of Eu2+ emission to Eu3+ emission in Sr3B2O6:Eu by using SrB4O7:Eu2+ as a precursor. Divalent europium emission in Sr3Y2(BO3)4 has not been reported in the literature. To look for Eu2+ emission, we prepared samples of Sr3Y2(BO3)4 by using Sr3B2O6 and SrB4O7 precursors. Samples of SrB4O7:Eu precursor were prepared using traditional methods: grinding stoichiometric amounts of strontium carbonate, boric acid, and europium oxide and firing in a reducing atmosphere. To make the Sr3B2O6:Eu precursor, portions of the SrB4O7:Eu precursor were ground with stoichiometric amounts of SrCO3, and samples were fired in a reducing atmosphere again. To transform the precursors, the SrB4O7 precursor was ground with stoichiometric amounts of yttrium oxide and strontium carbonate, and fired in a reduction furnace. Sr3B2O6 precursor was ground with stoichiometric amounts of yttrium oxide and boric acid, and fired in a reduction furnace. We show that undoped samples of Sr3B2O6 and SrB4O7 can be transformed phase-pure to Sr3Y2(BO3)4. This method may lead to previously unmade novel phosphors.

Faculty Mentor(s)

Anthony Diaz

Additional Mentoring Department

Chemistry

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May 16th, 4:50 PM May 16th, 5:10 PM

New Synthesis of Novel Phosphor for LED Technology: Sr3Y2(BO3)4:Eu Using Sr3B2O6:Eu and SrB4O7:Eu Precursors

SURC 137B

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 divalent europium (Eu2+). Depending on the host, this dopant can emit anywhere in the visible spectrum. However, in many host compounds, it is difficult to dope Eu2+ due to the stability of trivalent europium (Eu3+). The literature indicates that the phosphor SrB4O7 readily incorporates Eu2+ into its structure, but that Sr3B2O6 does not. Here, we show that we can increase the ratio of Eu2+ emission to Eu3+ emission in Sr3B2O6:Eu by using SrB4O7:Eu2+ as a precursor. Divalent europium emission in Sr3Y2(BO3)4 has not been reported in the literature. To look for Eu2+ emission, we prepared samples of Sr3Y2(BO3)4 by using Sr3B2O6 and SrB4O7 precursors. Samples of SrB4O7:Eu precursor were prepared using traditional methods: grinding stoichiometric amounts of strontium carbonate, boric acid, and europium oxide and firing in a reducing atmosphere. To make the Sr3B2O6:Eu precursor, portions of the SrB4O7:Eu precursor were ground with stoichiometric amounts of SrCO3, and samples were fired in a reducing atmosphere again. To transform the precursors, the SrB4O7 precursor was ground with stoichiometric amounts of yttrium oxide and strontium carbonate, and fired in a reduction furnace. Sr3B2O6 precursor was ground with stoichiometric amounts of yttrium oxide and boric acid, and fired in a reduction furnace. We show that undoped samples of Sr3B2O6 and SrB4O7 can be transformed phase-pure to Sr3Y2(BO3)4. This method may lead to previously unmade novel phosphors.