ULTRA-LOW REFLECTANCE BROADBAND OMNI-DIRECTIONAL ANTI-REFLECTION COATING

• US 20110120554A1
• Filed: 03/27/2009
• Published: 05/26/2011
• Est. Priority Date: 03/27/2008
• Status: Abandoned Application

• Current Assignee: Rensselaer Polytechnic Institute
• Original Assignee: Rensselaer Polytechnic Institute
• Inventors: Kuo, Mei-Ling, Mont, Frank W., Chhajed, Sameer, Lin, Shawn-Yu, Poxson, David J., Schubert, Martin F., Schubert, E. Fred, Kim, Jong Kyu
• Application Number:
  US12/736,278
• Publication Number:
  US 20110120554A1
• Time in Patent Office: Days
• US Class Current: 136/259
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
• CPC Class Codes: C09D 5/006 Anti-reflective coatings
• CPC Class Codes: G02B 1/115 Multilayers
• CPC Class Codes: H01L 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10T 428/24124 Fibers
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/249924 Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity
• CPC Class Codes: Y10T 428/249962 Void-containing component has a continuous matrix of fibers only [e.g., porous paper, etc.]

Abstract

An anti-reflection coating has an average total reflectance of less than 10%, for example less than 5.9% such as from 4.9% to 5.9%, over a spectrum of wavelengths of 400-1100 nm and a range of angles of incidence of 0-90 degrees with respect to a surface normal of the anti-reflection coating. An anti-reflection coating has a total reflectance of less than 10%, for example less than 6% such as less than 4%, over an entire spectrum of wavelengths of 400-1600 nm and an entire range of angles of incidence of 0-70 degrees with respect to a surface normal of the anti-reflection coating.

Claims

1. An anti-reflection coating, wherein the anti-reflection coating has an average total reflectance of less than 10% over a spectrum of wavelengths of 400-1100 nm and a range of angles of incidence of 0-90 degrees with respect to a surface normal of the anti-reflection coating.

2. The anti-reflection coating of claim 1, wherein the anti-reflection coating has an average total reflectance of from 4.9 to 10% over a spectrum of wavelengths of 400-1100 nm and a range of angles of incidence of 0-90 degrees with respect to a surface normal of the anti-reflection coating.

3. The anti-reflection coating of claim 1, comprising at least one porous layer and at least one non-porous layer.

4. The anti-reflection coating of claim 3, wherein the at least one porous layer comprises nano-scale structures or porous silica.

5. The anti-reflection coating of claim 3, wherein the at least one porous layers comprises one or more slanted nanorod layers.

6. The anti-reflection coating of claim 5, wherein:

the one or more slanted nanorod layers comprises at least a first slanted nanorod layer and a second slanted nanorod layer located over the first slanted nanorod layer;

the first slanted nanorod layer has a first porosity; and

the second slanted nanorod layer has a second porosity greater than the first porosity.

7. The anti-reflection coating of claim 6, wherein:

the first slanted nanorod layer comprises nanorods slanted in a first direction; and

the second slanted nanorod layer comprises nanorods slanted in a second direction different from the first direction.

8. The anti-reflection coating of claim 6, further comprising a barrier layer located between the first slanted nanorod layer and the second slanted nanorod layer.

9. The anti-reflection coating of claim 8, wherein the barrier layer is transparent and chemically resistive.

10. The anti-reflection coating of claim 5, wherein:

the one or more slanted nanorod layers comprise nanorods made of at least one of silicon oxide, titanium oxide, silicon oxynitride, aluminum oxide, zinc oxide, transparent organic materials, or combinations thereof;

each of the one or more slanted nanorod layers has a thickness of 20 nm to 500 nm; and

the one or more slanted nanorod layers having a porosity from 10% to 90%

11. The anti-reflection coating of claim 5, wherein:

the one or more slanted nanorod layers comprise nanorods made of at least one of silicon oxide, titanium oxide, silicon oxynitride, aluminum oxide, zinc oxide, transparent organic materials, or combinations thereof;

each of the one or more slanted nanorod layers has a thickness of 20 nm to 100 nm; and

the nanorods have a tilt angle of 0 to 60 degrees with respect to surface normal.

12. The anti-reflection coating of claim 3, wherein:

the anti-reflection coating comprises at least three layers having index of refraction values that vary discretely from about 3.6 to about 1; and

an index of refraction profile of the anti-reflection coating has an approximate Gaussian or Quintic distribution and is smooth to a first derivative and a second derivative.

13. The anti-reflection coating of claim 3, wherein:

the anti-reflection coating comprises at least three layers having index of refraction values that vary discretely from about 2.6 to about 1.09; and

an index of refraction profile of the anti-reflection coating has an approximate Gaussian or Quintic distribution and is smooth to a first derivative and a second derivative.

14. The anti-reflection coating of claim 3, wherein:

the anti-reflection coating has a continuous index of refraction profile varying from about 3.6 to about 1; and

the index of refraction profile has an approximate Gaussian or Quintic distribution.

15. The anti-reflection coating of claim 3, wherein:

the anti-reflection coating has a continuous index of refraction profile varying from about 2.6 to about 1.09; and

the index of refraction profile has an approximate Gaussian or Quintic distribution.

16. The anti-reflection coating of claim 3, wherein:

the at least one non-porous layer has an index of refraction of greater than 1.5; and

the at least one porous layer has an index of refraction of 1.1 to 1.25 and a porosity of 90-95%.

17. The anti-reflection coating of claim 1, wherein:

the anti-reflection coating has a total thickness of 1-5 optical wavelengths;

the anti-reflection coating comprises at least three layers; and

each of the at least three layers has a thickness of around 100 nm or less.

18. A solar cell, comprising:

a first electrode located over a substrate;

at least one photovoltaic layer located over the first electrode;

a second electrode located over the at least one photovoltaic layer; and

the anti-refection coating according to claim 1 located over the second electrode.

19. (canceled)

20. An anti-reflection coating, wherein the anti-reflection coating has a total reflectance of less than 10% over an entire spectrum of wavelengths of 400-1600 nm and an entire range of angles of incidence of 0-70 degrees with respect to a surface normal of the anti-reflection coating.

21. The anti-reflection coating of claim 20, wherein the anti-reflection coating has a total reflectance of less than 6% over a spectrum of wavelengths of 400-1600 nm and an entire range of angles of incidence of 0-70 degrees with respect to a normal to a surface normal of the anti-reflection coating.

22-39. -39. (canceled)

40. An anti-reflection coating, comprising:

one or more titanium oxide layers;

one or more intermixed layers located over the one or more titanium oxide layers; and

one or more slanted nanorod layers, the one or more slanted nanorod layers being located over the one or more intermixed layers.

41-54. -54. (canceled)

55. An anti-reflection coating located over a substrate, the anti-reflection coating comprising:

one or more non-porous layers;

a first slanted nanorod layer having a first porosity located over the non-porous layer; and

a second slanted nanorod layer having a second porosity located over the first slanted nanorod layer.

56. The anti-reflection coating of claim 55, wherein:

the first slanted nanorod layer comprising a first plurality of nanorods slanted in a first direction; and

the second slanted nanorod layer comprising a second plurality of nanorods slanted in a second direction different from the first direction.

57. The anti-reflection coating of claim 55, wherein:

the first nanorod layer and the second nanorod layer comprise independently at least one of silicon oxide, titanium oxide, silicon oxynitride, aluminum oxide, zinc oxide, transparent organic materials, or combinations thereof;

each of the first and second slanted nanorod layers has a thickness of 20 nm to 500 nm;

the second porosity is greater than the first porosity.

58. The anti-reflection coating of claim 55, wherein:

the anti-reflection coating further comprises a third slanted nanorod layer having a third porosity located over the second slanted nanorod layer; and

the third porosity is greater than the second porosity.

59. The anti-reflection coating of claim 55, further comprising a barrier layer located between the first slanted nanorod layer and the second slanted nanorod layer.

60. The anti-reflection coating of claim 59, wherein the barrier layer is transparent and chemically resistive.

61. The anti-reflection coating of claim 55, wherein:

the anti-reflection coating has an index of refraction profile varying discretely from about 3.6 to about 1; and

the index of refraction profile of the anti-reflection coating has an approximate Gaussian or Quintic distribution and is smooth to first derivative and second derivative.

64. The anti-reflection coating of claim 55, wherein:

the anti-reflection coating has a continuous index of refraction profile varying from about 2.6 to about 1.09; and

the index of refraction profile has an approximate Gaussian or Quintic distribution.

62-63. -63. (canceled)

65. (canceled)

66. An anti-reflection coating, comprising:

a first slanted nanorod layer having a first porosity; and

a second slanted nanorod layer having a second porosity located over the first slanted nanorod layer;

wherein the index of refraction profile of the anti-reflection coating has an approximate Gaussian distribution.

67-76. -76. (canceled)

77. A method of making an anti-reflection coating, comprising:

depositing one or more titanium oxide layers;

depositing one or more co-sputtered layers of titanium oxide and silicon oxide over the one or more titanium oxide layers; and

depositing one or more slanted nanorod layers over the one or more co-sputtered layers titanium oxide and silicon oxide.

78. The method of claim 77, wherein the step of depositing one or more slanted nanorod layers comprises:

depositing a first slanted nanorod layer having a first porosity;

depositing a second slanted nanorod layer having a second porosity located over the first slanted nanorod layer; and

the second porosity is greater than the first porosity.

80. The method of claim 78, wherein:

the first slanted nanorod layer comprising nanorods slanted in a first direction; and

the second slanted nanorod layer comprising nanorods slanted in a second direction different from the first direction.

81. The method of claim 78, further comprising depositing a barrier layer over the first slanted nanorod layer, prior to the step of depositing the second slanted nanorod layer.

82. The anti-reflection coating of claim 81, wherein the barrier layer is transparent and chemically resistive.

83. The method of claim 77, wherein the step of depositing one or more slanted nanorod layers comprises depositing slanted nanorods with a predetermined tilt angle and porosity by oblique angle deposition.

84. The method of claim 77, wherein:

during the step of depositing one or more slanted nanorod layers, a plurality of pores are formed between the nanorods; and

during the step of depositing the one or more co-sputtered layers or the step of depositing the one or more titanium oxide layers, substantially no pores are formed.

86. The method of claim 77, wherein an index of refraction profile of the anti-reflection coating is graded and varies from about 3.6 to about 1.

88. The method of claim 77, wherein, during the step of depositing the one or more co-sputtered layers at least one of sputtering parameters varies in real time in such a way that the one or more co-sputtered layers has a continuous composition profile, providing a continuous index of refraction profile.

89. The method of claim 77, further comprising:

depositing a first electrode located over a substrate;

depositing at least one photovoltaic layer over the first electrode;

depositing a second electrode over the at least one photovoltaic layer, prior to the step of depositing the one or more titanium oxide layers.

79. (canceled)

85. (canceled)

87. (canceled)