EFFICIENCY ENHANCEMENT OF SOLAR CELLS USING LIGHT MANAGEMENT

• US 20110315219A1
• Filed: 03/09/2010
• Published: 12/29/2011
• Est. Priority Date: 03/09/2009
• Status: Abandoned Application

• Current Assignee: University of North Carolina At Charlotte (University of North Carolina System)
• Original Assignee: University of North Carolina At Charlotte (University of North Carolina System)
• Inventors: Hasan, Mohamad-Ali, Fiddy, Michael A., Goveas, Terence A.
• Application Number:
  US13/255,487
• Publication Number:
  US 20110315219A1
• Time in Patent Office: Days
• US Class Current: 136/257
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: H01L 31/02322 comprising luminescent members, e.g. fluorescent sheets upon the device
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/03529 Shape of the potential jump barrier or surface barrier
• 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: H01L 31/055 where light is absorbed and re-emitted at a different wavelength by the optical element directly associated or integrated with the PV cell, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

A photovoltaic cell includes a junction, formed from an n-type semiconductor material and a p-type semiconductor material, a trench, opening toward the light-incident side of the junction, for trapping reflected light, and two photon conversion layers. A first photon conversion layer, arranged at the light-incident side of the junction, converts photons from a higher energy to a lower energy suitable for absorption by the semiconductor material, and a second photon conversion layer, arranged at the opposite side of the junction, converts photons from a lower energy to a higher energy suitable for absorption by the semiconductor material.

Claims

1. A photovoltaic cell comprising:

a junction formed from an n-type semiconductor material and a p-type semiconductor material and having a light-incident side and an opposite side;

a trench, opening toward the light-incident side of the junction, for trapping reflected light;

a first photon conversion layer that converts photons from a higher energy to a lower energy suitable for absorption by the semiconductor material; and

a second photon conversion layer that converts photons from a lower energy to a higher energy suitable for absorption by the semiconductor material.

2. The photovoltaic cell of claim 1, wherein the trench includes a top, a lowermost surface, and at least one plateau elevated above the lowermost surface but disposed below the top of the trench.

3. The photovoltaic cell of claim 2, wherein the trench further includes an additional plateau disposed between the at least one plateau and the top of the trench.

4. The photovoltaic cell of claim 2, wherein the trench further includes an additional plateau disposed between the lowermost surface and the at least one plateau.

5. The photovoltaic cell of claim 2, wherein the at least one plateau is inclined or declined relative to other surfaces of the trench.

6. The photovoltaic cell of claim 2, wherein the lowermost surface is inclined or declined relative to other surfaces of the trench.

7. The photovoltaic cell of claim 1, wherein the second photon conversion layer is arranged on the opposite side of the junction.

8. The photovoltaic cell of claim 7, wherein the first photon conversion layer is arranged on the light-incident side of the junction.

9. The photovoltaic cell of claim 8, wherein the first photon conversion layer is an antireflective coating layer.

10. The photovoltaic cell of claim 7, wherein the second photon conversion layer includes phosphor particles embedded therein, the phosphor particles selected to convert photons passing through the junction unabsorbed from a lower energy to a higher energy.

11. The photovoltaic cell of claim 10, wherein the phosphor particles are nano-particles.

12. The photovoltaic cell of claim 10, wherein the phosphor particles are micro-particles.

13. The photovoltaic cell of claim 7, wherein the second photon conversion layer is a reflective coating layer.

14. The photovoltaic cell of claim 1, wherein the composition of the first photon conversion layer is selected to optimize subsequent absorption of the lower-energy photons, converted thereby, by the semiconductor material.

15. The photovoltaic cell of claim 1, wherein the composition of the second photon conversion layer is selected to optimize subsequent absorption of the higher-energy photons, converted thereby, by the semiconductor material.

16. The photovoltaic cell of claim 1, wherein an upper wall of the trench is inclined or declined relative to other surfaces of the trench.

17. The photovoltaic cell of claim 1, wherein a lower wall of the trench is inclined or declined relative to other surfaces of the trench.

18. The photovoltaic cell of claim 1, further comprising a hollow, opening toward the opposite side of the junction, for minimizing carrier travel path to one or more contacts, for minimizing attenuation of long wavelength light used for up-conversion, or both.

19. The photovoltaic cell of claim 18, further comprising an electrical contact disposed in the hollow.

20. The photovoltaic cell of claim 18, wherein the second photon conversion layer is arranged at least partially in the hollow.

21. The photovoltaic cell of claim 1, wherein at least a portion of the cross-section or profile of the trench is hexagonal in shape.

22. The photovoltaic cell of claim 21, wherein the hexagonally-shaped portion of the trench profile opens directly to the light-incident side of the junction.

23. The photovoltaic cell of claim 21, wherein the hexagonally-shaped portion of the trench profile opens to the light-incident side of the junction via a passage that is narrower than the width of the hexagonally-shaped portion.

24-98. -98. (canceled)