Ultra-low reflectance broadband omni-directional anti-reflection coating

Patent metadata

Field	Value
Publication number	US-11088291-B2
Application number	US-201615216933-A
Country	US
Kind code	B2
Filing date	Jul 22, 2016
Priority date	Mar 27, 2008
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

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.

First claim

What is claimed is:

1. A structure comprising:
a silicon substrate; and
an antireflection coating on the silicon substrate, the antireflection coating comprising:
two bottom layers made of titanium oxide;
three middle layers made of co-sputtered silicon oxide and titanium oxide; and
two top layers made of slanted silicon oxide nanorods, the slanted silicon oxide nanorods are tilted along the same direction, have a diameter of 20-30 nm, and have a rod-to-rod spacing of 50-100 nm.

2. The structure of claim 1 , wherein a first of the top two layers made of slanted silicon oxide nanorods has a refractive index of n=1.22, and a second of the top two layers made of slanted silicon oxide nanorods has a refractive index of n=1.09.

3. The structure of claim 2 , wherein the antireflection coating further comprises a barrier layer located between the two top layers made of slanted silicon oxide nanorods.

4. The structure of claim 1 , wherein the two top layers made of slanted silicon oxide nanorods having a porosity from 10% to 90%.

5. The structure of claim 1 , wherein the slanted silicon oxide nanorods have a tilt angle of 0 to 60 degrees with respect to surface normal.

6. The structure of claim 1 , wherein the antireflection coating has refraction index values varying 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.

7. The structure of claim 1 , wherein the antireflection coating has index of refraction values that vary discretely from about 2.6 to about 1.09; and an index of refraction profile of the antireflection coating has an approximate Gaussian or Quintic distribution and is smooth to a first derivative and a second derivative.

8. The structure of claim 1 , wherein the antireflection 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.

9. The structure of claim 1 , wherein the antireflection 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.

10. The structure of claim 1 , wherein the antireflection coating has a total thickness of 1-5 optical wavelengths.

11. The structure of claim 1 , which is a solar cell comprising a first electrode located over the substrate; at least one photovoltaic layer located over the first electrode; a second electrode located over the at least one photovoltaic layer; and the antireflection coating located over the second electrode.

12. The structure of claim 1 , wherein the antireflection coating is optically smooth to within about 1/10 λ.

13. The structure of claim 1 , wherein the antireflection coating has an angle average total reflectance of about 5.9% over a spectrum of wavelengths of 400-1100 nm and over angles of incidence ranging from 0-90 degrees with respect to a surface normal of antireflection coating.

14. The structure of claim 1 , wherein a first bottom layer has a thickness of 69 nm, a second bottom layer has a thickness of 78 nm, a first middle layer has a thickness of 81 nm, a second middle layer has a thickness of 101 nm, a third middle layer has a thickness of 113 nm, a first top layer has as thickness of 145 nm, and a second top layer has a thickness of 156 nm.

15. The structure of claim 1 , wherein the antireflection coating has an angle average total reflectance of 1-6% over a spectrum of wavelengths of 400-1600 nm and over angles of incidence ranging from 0-60 degrees with respect to a surface normal of the antireflection coating.

Assignees

• Rensselaer Polytech Inst

Inventors

• Chhajed Sameer
• Kim Jong Kyu
• Lin Shawn-Yu
• Kuo Mei-Ling
• Mont Frank W
• Poxson David J
• Schubert E Fred
• Schubert Martin F

Classifications

• H10F77/50

  Encapsulations or containers (for photovoltaic modules H10F19/80) · CPC title

• H10F77/315 Primary

  the coatings being antireflective or having enhancing optical properties · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title

• G02B1/115

  Multilayers · CPC title

• C09D5/006

  Anti-reflective coatings · CPC title