Luminescent device including nanofibers and light stimulable particles disposed on a surface of or at least partially within the nanofibers

• US 7,999,455 B2
• Filed: 11/13/2006
• Issued: 08/16/2011
• Est. Priority Date: 11/13/2006
• Status: Expired due to Fees

• Current Assignee: Research Triangle Institute
• Original Assignee: Research Triangle Institute
• Inventors: Han, Li, Davis, James Lynn, Ensor, David S., Andrady, Anthony L., Walls, Howard J.
• Primary Examiner(s): Ton; Toan
• Assistant Examiner(s): Hanley; Britt D
• Application Number:
  US11/559,260
• Publication Number:
  US 20080113214A1
• Time in Patent Office: 1,737 Days
• Field of Search: None
• US Class Current: 313/503
• CPC Class Codes: C09K 11/565 with zinc cadmium
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: D01D 5/0007 Electro-spinning non-woven fabrics produced by electro-spinning D04H1/728
• CPC Class Codes: D01F 11/00 Chemical after-treatment of artificial filaments or the like during manufacture
• CPC Class Codes: D04H 1/413 containing granules other than absorbent substances
• CPC Class Codes: D04H 1/42 characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
• CPC Class Codes: D04H 1/43838 Ultrafine fibres, e.g. microfibres
• CPC Class Codes: D06M 11/52 with selenium, tellurium, polonium or their compounds; with sulfur, dithionites or compounds containing sulfur and halogens, with or without oxygen; by sulfohalogenation with chlorosulfonic acid; by sulfohalogenation with a mixture of sulfur dioxide and free halogens
• CPC Class Codes: G02B 6/0008 the light being emitted at the end of the fibre
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder

Abstract

A device for stimulable light emission that includes a fiber mat of nanofibers having an average fiber diameter in a range between 100 and 2000 nm, and includes plural stimulable particles disposed in association with the nanofibers. The stimulable particles produce secondary light emission upon receiving primary light at a wavelength λ. The average fiber diameter is comparable in size to the wavelength λ in order to provide scattering sites within the fiber mat for the primary light. Various methods for making suitable luminescent nanofiber mats include: electrospinning a polymer solution including or not including the stimulable particles and forming from the electrospun solution nanofibers having an average fiber diameter between 100 and 2000 nm. Methods, which electrospin without the stimulable particles, introduce the stimulable particles during electrospinning or after electrospinning to the fibers and therefore to the resultant fiber mat.

Claims

1. A lighting device for stimulable light emission, comprising:

a fiber mat configured to receive a primary light at a visible wavelength λ

, and including,

nanofibers having an average fiber diameter in a range between 100 and 2000 nm, and

plural light stimulable particles disposed on a surface of or at least partially within a volume of the nanofibers and configured to produce secondary light emission upon receiving the primary light; and

said average fiber diameter of a size such that the nanofibers provide scattering sites within the fiber mat for the primary light and, within the fiber mat, at least one ray of the primary light is scattered multiple times and exits the fiber mat with the secondary light to visibly illuminate an object removed from the fiber mat.

2. The device of claim 1, wherein the average fiber diameter is in a range between 300 to 600 nm.

3. The device of claim 2, wherein the average fiber diameter is in a range between 400 nm to 500 nm.

4. The device of claim 1, wherein the average fiber diameter is in a range of 0.50 to 1.50 of the wavelength λ

.

5. The device of claim 4, wherein the average fiber diameter is in a range of 0.9 to 1.10 of the wavelength λ

.

6. The device of claim 1, wherein the wavelength λ

is in a range between 300 and 600 nanometers.

7. The device of claim 6, wherein the wavelength λ

is in a range between 400 and 500 nanometers.

8. The device of claim 1, wherein the fiber mat has a thickness in a range between 0.01 microns and 2,000 microns.

9. The device of claim 1, wherein the fiber mat has a thickness in a range between 1 to 500 microns.

10. The device of claim 1, wherein the stimulable particles comprise luminescent particles.

11. The device of claim 10, wherein the luminescent particles comprise at least one of phosphors, quantum dots, and nano-phosphors.

12. The device of claim 11, wherein the quantum dots comprise at least one of silicon, germanium, indium phosphide, indium gallium phosphide, indium phosphide, cadmium sulfide, cadmium selenide, lead sulfide, copper oxide, copper selenide, gallium phosphide, mercury sulfide, mercury selenide, zirconium oxide, zinc oxide, zinc sulfide, zinc selenide, zinc silicate, titanium sulfide, titanium oxide, and tin oxide.

13. The device of claim 11, wherein at least one of the phosphors and nono-phosphors comprise at least one of a rare-earth doped metal oxide including Y₂O₃:

Tb, Y₂O₃;

Eu³⁺, Lu₂O₃;

Eu³⁺, CaTiO₃;

Pr³⁺, CaO;

Er³⁺, and (GdZn)O;

Eu³⁺, a rare-earth doped yttrium aluminum garnet (YAG) including YAG;

Ce³⁺, a rare-earth doped zirconium oxide including ZrO₂;

Sm³⁺and ZrO₂;

Er³⁺, rare earth doped vanadates and phosphates including (YVO₄;

Eu) and (La,Ce,Tb)PO₄, doped materials having a host matrix including one Gd₂O₃, GdO₂S, PbO, ZnO, ZnS, and ZnSe and including one of a dopant of Eu, Tb, Tm and Mn, and metal-doped forms of zinc sulfide and zinc selenide including ZnS;

Mn²⁺and ZnS;

Cu⁺.

14. The device of claim 11, wherein at least one of the phosphors and nano-phosphors comprise at least one of rare-Earth doped YAG, rare-Earth doped ZnS, and rare-Earth doped ZnSe.

15. The device of claim 1, wherein the stimulable particles comprise a plurality of color-distinctive light emitters configured to produce respective secondary light emissions from the primary light.

16. The device of claim 15, wherein the primary light transmitted from the fiber mat and the secondary light emissions from the fiber mat produce a resultant white light having a color rendering index greater than 70.

17. The device of claim 15, wherein the primary light transmitted from the fiber mat and the secondary light emissions from the fiber mat produce a resultant white light having a color rendering index greater than 80.

18. The device of claim 15, wherein the secondary light emissions from the fiber mat produce a resultant white light having a color rendering index greater than 70.

19. The device of claim 15, wherein the secondary light emissions from the fiber mat produce a resultant white light having a color rendering index greater than 80.

20. The device of claim 1, wherein the stimulable particles are disposed on surfaces or within a volume of the nanofibers.

21. The device of claim 1, wherein the stimulable particles are entrained in the fiber mat.

22. The device of claim 1, further comprising:

a transparent encapsulant encasing the fiber mat.

23. The device of claim 1, further comprising:

a light emitting diode configured to produce the primary light.

24. The device of claim 23, further comprising:

a transparent encapsulant encasing the light emitting diode and the fiber mat.

25. The device of claim 1, wherein the nanofibers comprise organic fibers.

26. The device of claim 1, wherein the nanofibers comprise polymers including at least one of poly(alkyl acrylate), poly(methyl methacrylate), poly(ethylene oxide), polystyrene, polysulfone, polylactides, polycarbonate, polyamides, poly(vinyl alcohol), derivatives thereof, polysilicones, polysulfones, and combinations thereof.

27. The device of claim 1, wherein the nanofibers include additives to alter at least one of a refractive index and an electrical conductivity of the nanofibers in the fiber mat.

28. The device of claim 1, wherein the nanofibers comprise two groups of fibers.

29. The device of claim 28, wherein the two groups comprise fibers having different materials.

30. The device of claim 28, wherein the two groups comprise fibers having different average fiber diameters.

39. The device of claim 1, wherein the nanofibers comprise inorganic fibers.

40. The device of claim 1, wherein the fiber mat and the scattering sites within the fiber mat comprise an optical medium which mixes the primary light and the secondary light.

41. The device of claim 1, wherein the fiber mat and the scattering sites within the fiber mat comprise an optical medium which mixes the primary light and the secondary light to produce white light.

42. The device of claim 1, wherein the fiber mat and the scattering sites within the fiber mat comprise an optical medium which mixes the primary light and the secondary light to produce non-white light.

46. The device of claim 1, wherein the stimulable particles comprise phosphors and quantum dots.

47. The device of claim 1, wherein the stimulable particles disposed on the surface of or at least partially within the volume of the nanofibers are exposed on the surface of the nanofibers.

48. The device of claim 1, wherein the stimulable particles comprise particles emitting the secondary light upon illumination with a visible light greater than 350 nm for said primary light at a wavelength λ

to produce red, green, and blue emissions from the fiber mat.

49. The device of claim 1, wherein said average fiber diameter being comparable in size to the wavelength λ

provides for Mie scattering.

31. A lamp for illuminating an object, comprising:

a primary light source configured to emit a primary light at a visible wavelength λ

, and;

a fiber mat configured to receive the primary light and including,

nanofibers having an average fiber diameter in a range between 100 and 2000 nm, and

plural light stimulable particles disposed on a surface of or at least partially within a volume of the nanofibers and configured to produce secondary light emission upon receiving the primary light; and

said average fiber diameter of a size such that the nanofibers provide scattering sites within the fiber mat for the primary light and, within the fiber mat, at least one ray of the primary light is scattered multiple times and exits the fiber mat with the secondary light to visibly illuminate an object removed from the fiber mat.

32. The lamp of claim 31, wherein the average fiber diameter is in a range between 400 nm to 500 nm.

33. The lamp of claim 31, wherein the primary light source comprises a light emitting diode configured to emit said wavelength λ

in a range between 400 and 500 nanometers.

34. The lamp of claim 31, wherein the fiber mat has a thickness in a range between 1 to 500 microns.

35. The lamp of claim 31, wherein the stimulable particles comprise at least one of phosphors, quantum dots and nano-phosphors.

36. The lamp of claim 31, wherein the stimulable particles comprise a plurality of color-distinctive light emitters configured to produce respective secondary light emissions from the primary light.

37. The lamp of claim 31, further comprising:

a transparent encapsulant encasing the primary light source and the fiber mat.

38. The lamp of claim 31, wherein the primary light source comprise at least one of a light emitting diode, a light emitting diode array, a laser, and a laser diode array.

43. The lamp of claim 31, wherein the fiber mat and the scattering sites within the fiber mat comprise an optical medium which mixes the primary light and the secondary light.

44. The lamp of claim 31, wherein the fiber mat and the scattering sites within the fiber mat comprise an optical medium which mixes the primary light and the secondary light to produce white light.

45. The lamp of claim 31, wherein the fiber mat and the scattering sites within the fiber mat comprise an optical medium which mixes the primary light and the secondary light to produce non-white light.

50. A light scattering device comprising:

a fiber mat configured to receive a primary light at a visible wavelength λ

, and including,

nanofibers having an average fiber diameter in a range between 100 and 2000 nm, and

said average fiber diameter of a size such that the nanofibers provide scattering sites within the fiber mat for the primary light and, within the fiber mat, at least one ray of the primary light is scattered multiple times and exits the fiber mat with the secondary light to visibly illuminate an object removed from the fiber mat.

51. A lamp for illuminating an object, comprising:

a primary light source configured to emit a primary light at a visible wavelength λ

, and;

a fiber mat configured to receive the primary light and including,

nanofibers having an average fiber diameter in a range between 100 and 2000 nm, and

said average fiber diameter of a size such that the nanofibers provide scattering sites within the fiber mat for the primary light and, within the fiber mat, at least one ray of the primary light is scattered multiple times and exits the fiber mat with the secondary light to visibly illuminate an object removed from the fiber mat.