# US 2014/0190559 A1 · Monolithic multiple solar cells > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190559 A1 - Document ID: US20140190559A1 - Status: Published application - Kind: A1 - Application number: 14/203,696 - Filed: 2014-03-11 - Published: 2014-07-10 - Earliest claimed: 2005-01-04 - Assignees: AZUR SPACE Solar Power GmbH - Applicants: AZUR SPACE Solar Power GMBH - Inventors: Matthias MEUSEL; Gerhard STROBL; Frank DIMROTH; Andreas BETT - Web page: https://patentgrep.com/patent/US20140190559A1 ## CPC - H10F 10/161: comprising multiple PN heterojunctions, e.g. tandem cells - H10F 10/142: comprising multiple PN homojunctions, e.g. tandem cells - H10F 10/163: comprising only Group III-V materials, e.g. GaAs/AlGaAs or InP/GaInAs photovoltaic cells - H10F 10/164: comprising heterojunctions with Group IV materials, e.g. ITO/Si or GaAs/SiGe photovoltaic cells - H10F 19/10: comprising photovoltaic cells in arrays in a single semiconductor substrate, the photovoltaic cells having vertical junctions or V-groove junctions - H10F 77/1248: {having three or more elements, e.g. GaAlAs, InGaAs or InGaAsP} - H10F 77/315: {the coatings being antireflective or having enhancing optical properties} - H10F 77/413: {directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42)} - H10F 77/48: Back surface reflectors [BSR] - H10F 77/488: {Reflecting light-concentrating means, e.g. parabolic mirrors or concentrators using total internal reflection} - H10F 77/63: Arrangements for cooling directly associated or integrated with photovoltaic cells, e.g. heat sinks directly associated with the photovoltaic cells or integrated Peltier elements for active cooling - Y02E 10/52: PV systems with concentrators - Y02E 10/544: Solar cells from Group III-V materials - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## 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. ## Claims ### Claim 1 A solar cell comprising: a first cell absorbing a first portion of incident light to thereby generate a first current; a second cell formed of GaInNAs, 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; 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; 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. ### Claim 2 (depends on 1) The solar cell according to claim 1, further comprising a fourth cell, a fifth cell, and/or a sixth cell, each of the fourth fifth and sixth cell absorbing a portion of the incident light to thereby generate a current. ### Claim 3 (depends on 1) the solar cell according to claim 1, wherein the second cell has a thickness between 800 nm to 2000 nm. ### Claim 4 (depends on 1) The solar cell according to claim 1, wherein each of the plurality of layers of the semiconductor mirror have a thickness between 10 nm and 150 nm, and wherein a half width value of reflection of the semiconductor mirror being in a range between 50 nm to 300 nm. ### Claim 5 (depends on 1) The solar cell according to claim 1, further comprising a fourth cell, wherein the first cell is formed of GaInP and the fourth cell is formed of GaInAs. ### Claim 6 (depends on 1) The solar cell according to claim 1, wherein fourth cell is arranged between the first cell and the second cell. ### Claim 7 (depends on 1) The solar cell according to claim 1, wherein the semiconductor mirror is formed of at least ten layers. ### Claim 8 (depends on 1) 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. ### Claim 9 (depends on 1) 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. ### Claim 10 (depends on 1) 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. ### Claim 11 (depends on 1) 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. ### Claim 12 (depends on 1) The solar cell according to claim 1, wherein at least one layer of the semiconductor mirror contains aluminum. ### Claim 13 (depends on 1) 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. ### Claim 14 (depends on 1) 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. ### Claim 15 The solar cell according to clam 1, wherein the layers of the semiconductor mirror are doped with at least one of Si, Te, Zn, C, Mg and Se. ### Claim 16 (depends on 1) 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. ### Claim 17 (depends on 1) 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. ### Claim 18 (depends on 1) The solar cell according to claim 1, wherein the semiconductor mirror is made of GaInAs and/or AlGaAs and/or AlGaInAs. ### Claim 19 (depends on 1) The solar cell according to claim 1, further comprising a substrate formed of Ge. ### Claim 20 (depends on 1) 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. ### Claim 21 (depends on 1) 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. ### Claim 22 (depends on 1) The solar cell according to claim 1, wherein the second cell has a band gap between 1.0 and 1.1 eV.