Compound based on an alkaline-earth metal, sulphur and aluminium, gallium or indium, its method of preparation and its use as a phosphor

• US 6,926,848 B2
• Filed: 01/13/2004
• Issued: 08/09/2005
• Est. Priority Date: 06/13/2001
• Status: Expired due to Term

• Current Assignee: Rhodia Electronics & Catalysis
• Original Assignee: Rhodia Electronics & Catalysis
• Inventors: Le Roux, Olivier, Le Mercier, Thierry
• Primary Examiner(s): Koslow, C. Melissa
• Application Number:
  US10/755,481
• Publication Number:
  US 20040140454A1
• Time in Patent Office: 574 Days
• Field of Search: 252/301.4 S
• US Class Current: 252/301.40S
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/7703 with alkaline earth metals
• CPC Class Codes: C09K 11/7731 with alkaline earth metals

Abstract

The invention relates to a compound based on at least one element A chosen from alkaline-earth metals, on at least one element B chosen from aluminium, gallium and indium, on sulphur and on a dopant capable of giving the compound luminescence properties, which is characterized in that it is in the form of a mixture of predominantly an AB₂S₄-type crystallographic phase and a B₂S₃-type crystallographic phase. This compound is prepared by a method in which a solution or suspension comprising salts or sols of the elements A, B and of the dopant is formed in a proportion such that the B/(A+dopant) atomic ratio is at least 2.06; the solution or suspension is spray-dried; the product thus obtained is sulphurized. This compound may be used as a phosphor, especially in cathodoluminescence.

Claims

1. A composition of matter based on at least one element A chosen from alkaline-earth metals, on at least one element B chosen from aluminium, gallium and indium, on sulphur and on a dopant imparting to the composition luminescence properties, and comprising a mixture of predominantly an AB₂S₄-type crystallographic phase and a B₂S₃-type crystallographic phase, wherein the composition is obtained by a process in which the elements A, B and the dopant are used in a proportion such that an atomic ratio B/(A+dopant) is at least 2.06, wherein the dopant comprises europium^II or ytterbium^II.

2. The composition of matter according to claim 1, wherein the composition is in powder form, and constituent particles of the powder have a mean size of at most 10 μ

m.

3. The composition of matter according to claim 2, wherein the constituent particles of the powder have a spherical shape.

4. The composition of matter according to claim 2, wherein the constituent particles of the powder include a transparent oxide coating layer.

5. The composition of matter according to claim 1, wherein the atomic ratio is 2.06 to 2.25.

6. The composition of matter according to claim 1, wherein the element A is strontium.

7. The composition of matter according to claim 6, wherein the atomic ratio is 2.06 to 2.25.

8. A cathodoluminescent or photoluminescent device, wherein the device comprises the composition of matter according to claim 1.

9. The composition of matter according to claim 4, wherein the transparent oxide coating layer includes silicon oxide, aluminium oxide, zirconium oxide, titanium oxide, zirconium silicate or rare-earth metal oxide.