Monolithic multiple solar cells

Patent metadata

Field	Value
Publication number	US-9252313-B2
Application number	US-201414203669-A
Country	US
Kind code	B2
Filing date	Mar 11, 2014
Priority date	Jan 4, 2005
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

A monolithic multiple solar cell includes at least three partial cells, with a semiconductor mirror placed between two partial cells. The aim of the invention is to improve the radiation stability of said solar cell. For this purpose, the semiconductor mirror has a high degree of reflection in at least one part of a spectral absorption area of the partial cell which is arranged above the semiconductor mirror and a high degree of transmission within the spectral absorption range of the partial cell arranged below the semiconductor mirror.

First claim

What is claimed is:

1. A solar cell comprising:
a first cell formed of GaInP, the first cell absorbing a first portion of incident light to thereby generate a first current;
a second cell formed of GaInAs, the second cell arranged below the first cell in a direction of the incident light, the second cell absorbing a second portion of the incident light to thereby generate a second current, the second cell having a thickness between 800 nm to 2000 nm;
a semiconductor mirror arranged below the second cell in the direction of incident light, the semiconductor mirror reflecting a non-absorbed portion of the second portion of light back towards the second cell thereby the absorption of the second portion of the incident light is increased in the second cell, the semiconductor mirror comprising a plurality of layers, each of the plurality of layers having a thickness between 10 nm and 150 nm, a half width value of reflection of the semiconductor mirror being in a range between 50 nm to 300 nm; and
a third cell formed of Ge, the third cell arranged below the semiconductor mirror, the third cell absorbing a third portion of the incident light to thereby generate a third current.

2. The solar cell according to claim 1 , wherein the second cell is arranged directly under the first cell, wherein the semiconductor mirror is arranged directly under the second cell, or wherein the third cell is arranged directly under the semiconductor mirror.

3. The solar cell according to claim 1 , wherein the second cell is formed without a multi-quantum well.

4. The solar cell according to claim 1 , wherein the semiconductor mirror is formed of at least ten layers.

5. The solar cell according to claim 1 , wherein each layer of the plurality of layers of the semiconductor mirror is formed of a compound semiconductor material.

6. The solar cell according to claim 1 , wherein a first layer of the semiconductor mirror is lattice-matched with a directly adjacent cell.

7. The solar cell according to claim 1 , wherein at least one layer of the semiconductor mirror has a different refraction index than another layer of the semiconductor mirror.

8. The solar cell according to claim 1 , wherein the semiconductor mirror has a total thickness from 500 nm to 4000 nm, the total thickness being based on the direction of incident light.

9. The solar cell according to claim 1 , wherein at least two layers of the semiconductor mirror have a different thickness or a different refraction index or are made of different materials.

10. The solar cell according to claim 1 , wherein the semiconductor mirror is structured such that a higher degree of reflection is achieved for wavelengths of the incident light between 800 nm and 900 nm than wavelengths greater than 900 nm.

11. The solar cell according to claim 1 , wherein a first layer of the semiconductor mirror in a direction of incident light is made of GaInP.

12. The solar cell according to claim 1 , wherein at least one layer of the semiconductor mirror is formed from the Group III and the Group V of the periodic table.

13. The solar cell according to claim 1 , wherein at least one layer of the semiconductor mirror contains aluminum.

14. The solar cell according to claim 1 , wherein the reflection of the second portion of incident light from the semiconductor mirror to the second cell facilitates that the second cell generates a greater amount of current with a reduced thickness.

15. The solar cell according to claim 1 , wherein the second cell is formed without GaAsP.

16. The solar cell according to claim 1 , wherein the semiconductor mirror is structured such that a higher degree of transmission is achieved for wavelengths of the incident light greater than 900 nm than wave lengths less than 900 nm.

17. The solar cell according to claim 1 , wherein the semiconductor mirror has a transmission degree of radiation in a spectral absorption range of the third cell.

18. The solar cell according to claim 1 , wherein the layers of the semiconductor mirror are doped with at least one of Si, Te, Zn, C, Mg and Se.

19. The solar cell according to claim 1 , wherein the semiconductor mirror has at least two materials with a high difference in a refraction index being between 0.4 and 0.65.

20. The solar cell according to claim 1 , wherein the semiconductor mirror has materials with a band gap energy that is equal with or greater than the second cell.

21. The solar cell according to claim 1 , wherein the semiconductor mirror is made of GaInAs and/or AlGaAs and/or AlGaInAs.

22. The solar cell according to claim 1 , further comprising a substrate formed of Ge.

23. The solar cell according to claim 1 , wherein a reflection degree of the semiconductor mirror of radiation in at least one part of the spectral absorption range of the second cell is greater than 0.3 or greater than 0.7 or between a range of 0.7 and 1.

24. The solar cell according to claim 1 , wherein a transmission degree of the semiconductor mirror of radiation in a spectral absorption range of the third cell is greater than 0.5 or greater than 0.85 or in a range between 0.8 and 1.

Assignees

• Azur Space Solar Power Gmbh

Inventors

• Meusel Matthias
• Strobl Gerhard
• Dimroth Frank
• Bett Andreas

Classifications

• Y02E10/544

  Solar cells from Group III-V materials · CPC title

• Y02E10/52

  PV systems with concentrators · CPC title

• H10F77/1248

  having three or more elements, e.g. GaAlAs, InGaAs or InGaAsP · CPC title

• H10F77/488

  Reflecting light-concentrating means, e.g. parabolic mirrors or concentrators using total internal reflection · CPC title

• H10F77/413

  directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42) · CPC title