LIGHT HARVESTING SYSTEM EMPLOYING SURFACE FEATURES FOR EFFICIENT LIGHT TRAPPING

• US 20170170352A1
• Filed: 02/25/2017
• Published: 06/15/2017
• Est. Priority Date: 07/13/2010
• Status: Active Grant

• Current Assignee: Sergiy Victorovich Vasylyev
• Original Assignee: Sergiy Victorovich Vasylyev
• Inventors: Vasylyev, Sergiy
• Granted Patent: US 10,269,999 B2
• Time in Patent Office: Days
• CPC Class Codes: G01J 1/0407 Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
• CPC Class Codes: G01J 5/0853 having infrared absorbers other than the usual absorber layers deposited on infrared detectors like bolometers, wherein the heat propagation between the absorber and the detecting element occurs within a solid
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 5/0231 the surface having microprismatic or micropyramidal shape macroscopic prism arrays G02B5/045
• CPC Class Codes: G02B 5/0294 adapted to provide an additional optical effect, e.g. anti-reflection or filter
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216
• CPC Class Codes: H01L 31/0525 including means to utilise heat energy directly associated with the PV cell, e.g. integrated Seebeck elements
• CPC Class Codes: H01L 31/0543 comprising light concentrating means of the refractive type, e.g. lenses
• CPC Class Codes: H01L 31/0547 comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

A light harvesting system employing a photoresponsive layer having a plurality of light input ports associated with a light input surface of the layer. Light received by the light input ports is admitted into the photoresponsive layer an incidence angle that is greater than a predetermined critical angle, such as the angle of the total internal reflection (TIR). The admitted light is retained in the photoresponsive layer and is propagated within the layer until it is substantially absorbed.

Claims

1. A light harvesting system, comprising:

a generally planar layer of photoresponsive material defined by a first broad-area surface configured for light input and an opposing second broad-area surface extending generally parallel to the first broad-area surface; and

a plurality of light input ports associated with the first broad-area surface,

wherein each of said light input ports is configured to admit light into said layer

at an incidence angle that is greater than a predetermined critical angle.

2. A light harvesting system as recited in claim 1, wherein said predetermined critical angle is an angle of the total internal reflection (TIR) characterizing at least one surface of said layer of photoresponsive material.

3. A light harvesting system as recited in claim 1, wherein a cumulative area of said light input ports is less than the area of the first broad-area surface.

4. A light harvesting system as recited in claim 1, wherein each of said plurality of light input ports is formed by a surface feature selected from the group consisting of surface interruptions, recesses, indentations, cavities, through holes, blind holes, grooves, diffraction gratings, holograms, textured areas, and light scattering elements.

5. A light harvesting system as recited in claim 1, wherein each of said plurality of light input ports is configured to trap light within said layer of photoresponsive material by at least enhancing the propagation path length through said photoresponsive material.

6. A light harvesting system as recited in claim 1, wherein said layer of photoresponsive material is a part of a photovoltaic cell.

7. A light harvesting system as recited in claim 6 further comprising at least one electrical contact.

8. A light harvesting system as recited in claim 7, wherein said electrical contact is made from an optically transmissive electroconductive material.

9. A light harvesting system as recited in claim 7, wherein said electrical contact is made from an opaque electroconductive material.

10. A light harvesting system as recited in claim 6, comprising a plurality of electrical contacts associated with the first broad-area surface, wherein said light input ports are formed in spaces between said electrical contacts.

11. A light harvesting system as recited in claim 1, comprising a planar array of light focusing elements, wherein each of said plurality of light input ports is disposed in energy receiving relationship with respect to at least one of said light focusing elements.

12. A light harvesting system as recited in claim 11, wherein each of said light focusing elements comprises a micro-lens having a configuration selected from the group consisting of linear, round, rectangular, square, and hexagonal.

13. A light harvesting system as recited in claim 11, wherein each of said plurality of light input ports is disposed in a predetermined alignment with each of said plurality of light focusing elements.

14. A light harvesting system as recited in claim 11, wherein said plurality of light input ports is disposed at a focal distance from said light focusing elements.

15. A light harvesting system as recited in claim 11, comprising an optically transmissive buffer layer disposed between said layer of photoresponsive material and said planar array of light focusing elements, wherein a refractive index of said buffer layer is lower than a refractive index of said layer of photoresponsive material.

16. A light harvesting system as recited in claim 1, comprising a planar array of micro-lenses each having a convex spherical shape, wherein a thickness T of the planar micro-lens array is defined by the following expression:

T≈

nR/n−

1, where R is a radius of curvature of the micro-lenses and n is the refractive index of the material of the micro-lenses.

17. A light harvesting system as recited in claim 1, comprising a plurality of surface relief features formed in a surface of a glass or polymeric material and configured for focusing light onto a plurality of areas that are substantially smaller than the areas of said surface relief features, wherein each of said plurality of light input ports is disposed in energy receiving relationship with respect to at least one of said surface relief features.

18. A light harvesting system as recited in claim 1, wherein each of said plurality of light input ports comprises one or more refractive face inclined at an angle with respect to a prevailing plane of said layer of photoresponsive material.

19. A light harvesting system as recited in claim 1, wherein at least one of said plurality of light input ports comprises surface relief features formed in said first broad-area surface, wherein at least one of said surface relief features is configured to receive a light ray incident onto said the first broad-area surface at a first angle with respect to a normal to said layer of photoresponsive material and admit said ray into said layer of photoresponsive material at a second angle with respect to said normal, wherein the second angle is greater than the first angle.

20. A light harvesting system as recited in claim 1, comprising a reflective layer disposed in contact with said second broad-area surface.