High-Efficiency, Monolithic, Multi-Bandgap, Tandem, Photovoltaic Energy Converters

A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

Interconnections for Mechanically Stacked Multijunction Solar Cells

Mechanically stacked multijunction solar cells are provided. In one embodiment, a mechanically stacked, multijunction solar cell comprises: a first solar cell having a first bandgap; a second solar cell having a second bandgap; and a plurality of spaced apart metal pillars sandwiched between the first solar cell and the second solar cell. 1. A mechanically stacked , multijunction solar cell comprising:a first solar cell having a first bandgap;a second solar cell having a second bandgap; anda plurality of spaced apart metal pillars sandwiched between the first solar cell and the second solar cell.2. The mechanically stacked claim 1 , multijunction solar cell according to claim 1 , further including an optically transparent bonding material between the plurality of spaced apart metal pillars claim 1 , wherein the optically transparent bonding material is also sandwiched between the first solar cell and the second solar cell.3. The mechanically stacked claim 2 , multijunction solar cell according to claim 2 , wherein the optically transparent bonding material comprises SiO.4. The mechanically stacked claim 2 , multijunction solar cell according to claim 2 , wherein the optically transparent bonding material comprises SiN.5. The mechanically stacked claim 2 , multijunction solar cell according to claim 2 , wherein the optically transparent bonding material comprises TiO.6. The mechanically stacked claim 2 , multijunction solar cell according to claim 2 , wherein the optically transparent bonding material comprises more than one layer of optically transparent materials claim 2 , wherein the more than one layer of optically transparent materials is configured to optimize optical transmission.7. The mechanically stacked claim 2 , multijunction solar cell according to claim 2 , wherein the optically transparent bonding material comprises more than one layer of optically transparent materials claim 2 , wherein the more than one layer of optically transparent materials is ...

LOW-BANDGAP, MONOLITHIC, MULTI-BANDGAP, OPTOELECTRONIC DEVICES

Low bandgap, monolithic, multi-bandgap, optoelectronic devices (), including PV converters, photodetectors, and LED's, have lattice-matched (LM), double-heterostructure (DH), low-bandgap GaInAs(P) subcells () including those that are lattice-mismatched (LMM) to InP, grown on an InP substrate () by use of at least one graded lattice constant transition layer () of InAsP positioned somewhere between the InP substrate () and the LMM subcell(s) (). These devices are monofacial () or bifacial () and include monolithic, integrated, modules (MIMs) () with a plurality of voltage-matched subcell circuits () as well as other variations and embodiments. 1. A monolithic , multi-bandgap , photovoltaic converter , comprising:a first subcell comprising GaInAs(P) with a first bandgap and a first lattice constant;{'sub': y', '1-y, 'a second subcell comprising GaInAs(P) with a second bandgap and a second lattice constant, wherein the second bandgap is less than the first bandgap and the second lattice constant is greater than the first lattice constant, and further, wherein the second lattice constant is equal to a lattice constant of a InAsPalloy with a bandgap greater than the first bandgap; and'}{'sub': y', '1-y, 'a lattice constant transition material positioned between the first subcell and the second subcell, said lattice constant transition material comprising InAsPalloy with a lattice constant that changes gradually from the first lattice constant to the second lattice constant.'}2. The monolithic claim 1 , multi-bandgap claim 1 , photovoltaic converter of claim 1 , wherein the lattice constant transition material is grown epitaxially on the first subcell with a gradually increasing value for y.3. The monolithic claim 1 , multi-bandgap claim 1 , photovoltaic converter of claim 1 , wherein the second subcell is grown epitaxially on the lattice constant transition material.4. The monolithic claim 1 , multi-bandgap claim 1 , photovoltaic converter of claim 1 , wherein the first ...

PHOTOVOLTAIC DEVICE

A multijunction photovoltaic device () is provided. The multijunction photovoltaic device () includes a substrate () and one or more intermediate sub-cells (-) coupled to the substrate (). The multijunction photovoltaic device () further includes a top sub-cell () comprising an AlInP alloy coupled to the one or more intermediate sub-cells (-) and lattice mismatched to the substrate (). 1. A multijunction photovoltaic device , comprising:a substrate;one or more intermediate sub-cells coupled to the substrate; and{'sub': x', '1-x, 'a top sub-cell comprising an AlInP alloy coupled to the one or more intermediate sub-cells and lattice mismatched to the substrate.'}2. The multijunction photovoltaic device of claim 1 , wherein the one or more intermediate sub-cells are lattice-mismatched to the substrate and the top sub-cell is lattice matched to the one or more intermediate sub-cells.3. The multijunction photovoltaic device of claim 1 , further comprising a transitional buffer layer positioned between the substrate and the one or more intermediate sub-cells.4. The multijunction photovoltaic device of claim 1 , wherein each of the one or more intermediate sub-cells comprises a bandgap lower than the bandgap of the AlInP top sub-cell.5. The multijunction photovoltaic device of claim 3 , wherein the AlInP top sub-cell has a bandgap greater than 1.75 eV.6. The multijunction photovoltaic device of claim 1 , further comprising a bottom sub-cell comprising an alloy including germanium or gallium arsenide positioned between the substrate and the one or more intermediate sub-cells.7. The multijunction photovoltaic device of claim 6 , further comprising a transitional buffer layer positioned between the bottom sub-cell and the one or more intermediate sub-cells and wherein the bottom sub-cell is lattice-matched to the substrate and lattice mismatched to the one or more intermediate sub-cells.8. A single junction photovoltaic device claim 6 , comprising:a substrate;a transitional ...

Low-bandgap, monolithic, multi-bandgap, optoelectronic devices

Low bandgap, monolithic, multi-bandgap, optoelectronic devices ( 10 ), including PV converters, photodetectors, and LED's, have lattice-matched (LM), double-heterostructure (DH), low-bandgap GaInAs(P) subcells ( 22, 24 ) including those that are lattice-mismatched (LMM) to InP, grown on an InP substrate ( 26 ) by use of at least one graded lattice constant transition layer ( 20 ) of InAsP positioned somewhere between the InP substrate ( 26 ) and the LMM subcell(s) ( 22, 24 ). These devices are monofacial ( 10 ) or bifacial ( 80 ) and include monolithic, integrated, modules (MIMs) ( 190 ) with a plurality of voltage-matched subcell circuits ( 262, 264, 266, 270, 272 ) as well as other variations and embodiments.

LOW-BANDGAP, MONOLITHIC, MULTI-BANDGAP, OPTOELECTRONIC DEVICES

Low bandgap, monolithic, multi-bandgap, optoelectronic devices (), including PV converters, photodetectors, and LED's, have lattice-matched (LM), double-heterostructure (DH), low-bandgap GaInAs(P) subcells () including those that are lattice-mismatched (LMM) to InP, grown on an InP substrate () by use of at least one graded lattice constant transition layer () of InAsP positioned somewhere between the InP substrate () and the LMM subcell(s) (). These devices are monofacial () or bifacial () and include monolithic, integrated, modules (MIMs) () with a plurality of voltage-matched subcell circuits () as well as other variations and embodiments. 1. A monolithic , multi-bandgap , photovoltaic converter , comprising:a first subcell comprising GaInAs(P) with a first bandgap and a first lattice constant;{'sub': y', '1−y, 'a second subcell comprising GaInAs(P) with a second bandgap and a second lattice constant, wherein the second bandgap is less than the first bandgap and the second lattice constant is greater than the first lattice constant, and further, wherein the second lattice constant is equal to a lattice constant of a InAsPalloy with a bandgap greater than the first bandgap; and'}{'sub': y', '1−y, 'a lattice constant transition material positioned between the first subcell and the second subcell, said lattice constant transition material comprising InAsPalloy with a lattice constant that changes gradually from the first lattice constant to the second lattice constant.'}2. The monolithic claim 1 , multi-bandgap claim 1 , photovoltaic converter of claim 1 , wherein the lattice constant transition material is grown epitaxially on the first subcell with a gradually increasing value for y.3. The monolithic claim 1 , multi-bandgap claim 1 , photovoltaic converter of claim 1 , wherein the second subcell is grown epitaxially on the lattice constant transition material.4. The monolithic claim 1 , multi-bandgap claim 1 , photovoltaic converter of claim 1 , wherein the first ...

High bandgap iii-v alloys for high efficiency optoelectronics

High bandgap alloys for high efficiency optoelectronics are disclosed. An exemplary optoelectronic device may include a substrate, at least one Al1-xInxP layer, and a step-grade buffer between the substrate and at least one Al1-xInxP layer. The buffer may begin with a layer that is substantially lattice matched to GaAs, and may then incrementally increase the lattice constant in each sequential layer until a predetermined lattice constant of Al1-xInxP is reached.

Electrical isolation of component cells in monolithically interconnected modules

A monolithically interconnected photovoltaic module having cells which are electrically connected which comprises a substrate, a plurality of cells formed over the substrate, each cell including a primary absorber layer having a light receiving surface and a p-region, formed with a p-type dopant, and an n-region formed with an n-type dopant adjacent the p-region to form a single pn-junction, and a cell isolation diode layer having a p-region, formed with a p-type dopant, and an n-region formed with an n-type dopant adjacent the p-region to form a single pn-junction, the diode layer intervening the substrate and the absorber layer wherein the absorber and diode interfacial regions of a same conductivity type orientation, the diode layer having a reverse-breakdown voltage sufficient to prevent inter-cell shunting, and each cell electrically isolated from adjacent cells with a vertical trench trough the pn-junction of the diode layer, interconnects disposed in the trenches contacting the absorber regions of adjacent cells which are doped an opposite conductivity type, and electrical contacts.

High bandgap iii-v alloys for high efficiency optoelectronics

Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps

Modeling a monolithic, multi-bandgap, tandem, solar photovoltaic converter or thermophotovoltaic converter by constraining the bandgap value for the bottom subcell to no less than a particular value produces an optimum combination of subcell bandgaps that provide theoretical energy conversion efficiencies nearly as good as unconstrained maximum theoretical conversion efficiency models, but which are more conducive to actual fabrication to achieve such conversion efficiencies than unconstrained model optimum bandgap combinations. Achieving such constrained or unconstrained optimum bandgap combinations includes growth of a graded layer transition from larger lattice constant on the parent substrate to a smaller lattice constant to accommodate higher bandgap upper subcells and at least one graded layer that transitions back to a larger lattice constant to accommodate lower bandgap lower subcells and to counter-strain the epistructure to mitigate epistructure bowing.

Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps

Modeling a monolithic, multi-bandgap, tandem, solar photovoltaic converter or thermophotovoltaic converter by constraining the bandgap value for the bottom subcell to no less than a particular value produces an optimum combination of subcell bandgaps that provide theoretical energy conversion efficiencies nearly as good as unconstrained maximum theoretical conversion efficiency models, but which are more conducive to actual fabrication to achieve such conversion efficiencies than unconstrained model optimum bandgap combinations. Achieving such constrained or unconstrained optimum bandgap combinations includes growth of a graded layer transition from larger lattice constant on the parent substrate to a smaller lattice constant to accommodate higher bandgap upper subcells and at least one graded layer that transitions back to a larger lattice constant to accommodate lower bandgap lower subcells and to counter-strain the epistructure to mitigate epistructure bowing.

Disorder-order homojunctions as minority-carrier barriers

A method for improving the overall quantum efficiency and output voltage in solar cells using spontaneous ordered semiconductor alloy absorbers to form a DOH below the front or above the back surface of the cell.

Disorder-order homojunctions as minority-carrier barriers

A method for improving the overall quantum efficiency and output voltage in solar cells using spontaneous ordered semiconductor alloy absorbers to form a DOH below the front or above the back surface of the cell.

Monolithic multi-color light emission/detection device

A single-crystal, monolithic, tandem, multicolor optical transceiver device (100) is described, including (a) an InP substrate (102) having upper and lower surfaces, (b) a first junction (104) on the upper surface of the InP substrate, (c) a second junction (106) on the first junction. The first junction is preferably GaInAsP of defined composition, and the second junction is preferably InP. The two junctions are lattice matched. The second junction has a larger energy band gap than the first junction. Additional junctions (108) having successively larger energy band gaps may be included. The device is capable of simultaneous and distinct multicolor emission and detection over a single optical fiber.

Monolithic multi-color light emission/detection device

Disorder-order homojunctions as minority-carrier barriers

A method for improving the overall quantum efficiency and output voltage in solar cells using spontaneous ordered semiconductor alloy absorbers to form a DOH below the front or above the back surface of the cell.

High performance, high bandgap, lattice-mismatched, GaInP solar cells

High performance, high bandgap, lattice-mismatched, photovoltaic cells ( 10 ), both transparent and non-transparent to sub-bandgap light, are provided as devices for use alone or in combination with other cells in split spectrum apparatus or other applications.