All-perovskite tandem solar cell
By introducing a quantum well tunnel junction into an all-perovskite tandem solar cell, the problem of low recombination efficiency of traditional tunnel junctions is solved, achieving efficient recombination of electrons and holes and improving the photoelectric conversion efficiency of the cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING UNIV
- Filing Date
- 2023-12-14
- Publication Date
- 2026-06-19
AI Technical Summary
Traditional tunnel junction recombination efficiency is low, which limits the performance of tandem solar cells and makes it difficult to achieve complete electron-hole recombination.
By employing a quantum well tunnel junction structure, more heavily doped layers are introduced into the traditional tunnel junction to form a quantum well, thereby improving the binding and recombination efficiency of electrons and holes.
The open-circuit voltage, short-circuit current density, and fill factor of the all-perovskite tandem solar cell were improved, and the photoelectric conversion efficiency was increased from 22% to 25%.
Smart Images
Figure CN117460268B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solar cell technology, specifically relating to an all-perovskite tandem solar cell. Background Technology
[0002] Organic-inorganic hybrid metal halide perovskite materials have attracted much attention in photovoltaic devices due to their outstanding photoelectric properties, including long carrier diffusion distance, low defect density, and high light absorption coefficient. In the past decade, the performance of perovskite solar cells has become comparable to that of crystalline silicon solar cells. Their photoelectric conversion efficiency has increased from 3.8% in 2009 to 26% now, approaching the world record of 26.7% for crystalline silicon cells. They are very likely to become the next generation of solar cells in the photovoltaic market in the future.
[0003] The theoretical limit of traditional single-junction solar cells is only 33%. An effective way to break through the theoretical limit of single-junction is to prepare tandem solar cells. The theoretical limit of tandem devices at both ends can reach 45%. Among them, perovskite / perovskite tandem solar cells have attracted much attention in recent years and have made great progress. The highest certified efficiency has now exceeded 29%.
[0004] The structure of an all-perovskite tandem solar cell is relatively complex. It primarily consists of a wide-bandgap perovskite solar cell as the top cell to absorb short-wavelength sunlight, and a narrow-bandgap perovskite solar cell as the bottom cell to absorb long-wavelength sunlight. This maximizes the utilization of the solar spectrum's energy and reduces performance loss due to insufficient photon absorption. Furthermore, the relaxation loss of the all-perovskite tandem solar cell is relatively small. Additionally, there are electron-hole transport layers in both the top and bottom cells to extract and transport electrons and holes generated by light absorption in the perovskite. Because the tandem solar cell has a series structure, a tunneling junction is required to capture and recombine electrons and holes within the tandem layers, thereby achieving efficient series connection.
[0005] Traditional tunnel junctions can be composed of heavily doped n++ layers and heavily doped p++ layers, but they always have low recombination efficiency and cannot achieve complete recombination of electrons and holes, thus limiting the performance of stacked devices. Summary of the Invention
[0006] To address the carrier recombination problem in tandem solar cell devices, this invention provides an all-perovskite tandem solar cell containing a carrier trap tunnel junction.
[0007] The present invention adopts the following technical solution:
[0008] An all-perovskite tandem solar cell includes a transparent conductive substrate, a first sub-cell, a quantum well tunneling junction, a second sub-cell, and a back electrode arranged sequentially along the direction of sunlight incidence. The first sub-cell, the quantum well tunneling junction, and the second sub-cell are one of the following:
[0009] (1) The first sub-cell includes a first hole transport layer, a first perovskite layer and a first electron transport layer arranged sequentially along the direction of sunlight incident; the second sub-cell includes a second hole transport layer, a second perovskite layer and a second electron transport layer arranged sequentially along the direction of sunlight incident; the quantum well tunnel junction includes a first n++ layer, a second n++ layer, a third n++ layer, a first p++ layer, a second p++ layer and a third p++ layer arranged sequentially along the direction of sunlight incident.
[0010] Or (2) the first sub-cell includes a first electron transport layer, a first perovskite layer and a first hole transport layer arranged sequentially along the direction of sunlight incident, the second sub-cell includes a second electron transport layer, a second perovskite layer and a second hole transport layer arranged sequentially along the direction of sunlight incident, and the quantum well tunneling junction includes a first p++ layer, a second p++ layer, a third p++ layer, a first n++ layer, a second n++ layer and a third n++ layer arranged sequentially along the direction of sunlight incident.
[0011] Furthermore, the first n++ layer and the third n++ layer are made of the same material, while the first n++ layer and the second n++ layer are made of different materials.
[0012] Furthermore, the material of the first n++ layer is selected from C 60 C 70 The materials for the second n++ layer are graphene, PCBM, ICBA, Nb2O5, TiO2, SnO2, or ZnO; the materials for the second n++ layer are selected from undoped or doped C. 60 C 70 Graphene, PCBM, ICBA, Nb2O5, TiO2, SnO2, or ZnO, wherein the dopant is selected from organic compounds (Phlm, N-DMBI, N-DPBI) and metal ions (Mn). 7+ Mn 5+ Fe 3+ Mo 6+ ) and atoms (N, C, O).
[0013] Furthermore, the first p++ layer and the third p++ layer are made of the same material, while the first p++ layer and the second p++ layer are made of different materials.
[0014] Furthermore, the material of the first p++ layer is selected from PVK, MeO-2PACz, 2PACz, Me-4PACz, CuI, spiro-TTB, NiO, MoO3, Cu2O, CuI, CuPc, CuSCN, graphene redox, PTAA, PEDOT:PSS, and Poly-TPD; the material of the second p++ layer is selected from undoped or doped PVK, MeO-2PACz, 2PACz, Me-4PACz, CuI, spiro-TTB, NiO, MoO3, Cu2O, CuI, CuPc, CuSCN, graphene redox, PTAA, PEDOT:PSS, and Poly-TPD, wherein the doping is a metal ion (Mg). 2+ Mn 2+ Co 2+ Ga 3+ In 3+ Ce 3+ ) or atoms (Br, I, Cl).
[0015] Furthermore, the thickness of the second n++ layer is less than the thickness of the first n++ layer and the third n++ layer.
[0016] Furthermore, the thickness of the second p++ layer is less than the thickness of the first p++ layer and the third p++ layer.
[0017] The transparent conductive substrate can be any conventional product in the art, including indium tin oxide (ITO) substrates, indium tungsten oxide (IWO) substrates, fluorine-doped tin oxide (FTO) substrates, indium zinc oxide (IZO) substrates, aluminum-doped zinc oxide (AZO) substrates, etc.
[0018] The materials of the first hole transport layer and the second hole transport layer are selected from PVK, MeO-2PACz, 2PACz, Me-4PACz, CuI, spiro-TTB, NiO, MoO3, Cu2O, CuI, CuPc, CuSCN, redox graphene, PTAA, PEDOT:PSS, and Ploy-TPD.
[0019] The materials of the first electron transport layer and the second electron transport layer are selected from C. 60 C 70 Graphene, PCBM, ICBA, Nb2O5, TiO2, SnO2, ZnO.
[0020] The back electrode can be a continuous metal thin film, a metal nanoparticle thin film, or a non-dense metal island structure; the material can be gold, silver, copper, titanium, chromium, nickel, aluminum, etc.
[0021] The band gap of the first perovskite layer is larger than that of the second perovskite layer. The chemical formula of the perovskite in the perovskite layer is ABX3, where the A-site is a cesium ion (Cs). + ), Methylamino (MA) + ) or formamidinyl (FA + A mixture of one or more of these components in any proportion, with lead ions (Pb) at the B site. 2+ The X-position is an iodide ion (I). - ), bromide ions (Br) - ) or chloride ions (Cl - Mix one or more of them in any proportion.
[0022] The preparation methods of each layer of the quantum well tunnel junction described in this invention include spin coating, evaporation, blade coating, slot coating, magnetron sputtering, atomic layer deposition, and electron beam evaporation.
[0023] The preparation methods of the first hole transport layer and the second hole transport layer of the present invention include spin coating, electrochemical deposition, blade coating, slot coating, inkjet printing, evaporation, and electron beam evaporation.
[0024] The preparation methods of the first electron transport layer and the second electron transport layer of the present invention include spin coating, electrochemical deposition, blade coating, slot coating, inkjet printing, evaporation, and electron beam evaporation.
[0025] The preparation methods of the first and second perovskite layers of the present invention include spin coating, blade coating, slot coating, inkjet printing, and evaporation.
[0026] The quantum well tunneling junction structure of this invention introduces more heavily doped layers on the basis of the traditional tunneling junction, thereby creating quantum wells in the band structure of the tunneling junction. This facilitates the binding and recombination of electrons and holes, improves the open-circuit voltage, fill factor, and short-circuit current density of the all-perovskite tandem solar cell, and enhances the photoelectric conversion efficiency. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the structure of the all-perovskite tandem solar cell and tunnel junction of the present invention.
[0028] Figure 2 This is a schematic diagram of the band structure of a tunnel junction.
[0029] Figure 3 The diagram shows the device structure of Examples 1 and 2.
[0030] Figure 4 This is a performance comparison chart of the all-perovskite tandem solar cells of Example 1 and Example 2. Implementation
[0031] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.
[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.
[0033] Unless otherwise specified, all materials and reagents used in the following examples are commercially available. Example 1
[0034] 1. Clean the ITO transparent conductive substrate with tap water, then sonicate it in an ultrasonic machine for 15 minutes each with isopropanol and acetone. Dry the liquid on the surface of the ITO substrate after sonication with a nitrogen gas gun, and then treat it with a UV ozone generator for 15 minutes.
[0035] 2. A layer of [(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (Me-4PACz) with a thickness of approximately 10 nm was prepared on an ITO substrate after UV ozone treatment as the first hole transport layer.
[0036] 3. A wide-bandgap perovskite layer with a thickness of approximately 350-400 nm is prepared on the substrate on which the first hole transport layer has been prepared.
[0037] 4. Prepare a C layer on a wide-bandgap perovskite layer. 60 As the first electron transport layer, it has a thickness of approximately 26 nm.
[0038] 5. A conventional tunneling junction is fabricated on the first transport layer. Specifically, this is done by first fabricating a tunneling junction on the C... 60 A layer of MoO3 with a thickness of approximately 60 nm was prepared on the surface.
[0039] 6. A layer of PEDOT with a thickness of approximately 70 nm was prepared on a conventional tunnel junction as a second hole transport layer.
[0040] 7. A narrow bandgap perovskite layer with a thickness of approximately 800-2000 nm is prepared on the substrate of the second hole transport layer.
[0041] 8. Preparation of a fullerene (C) layer on a narrow bandgap perovskite layer 60 )+BCP serves as the second electron transport layer, where C 60 The thickness is approximately 26 nm, and the thickness of BCP is approximately 6 nm.
[0042] 9. Finally, a copper (Cu) layer was prepared as a metal electrode with a thickness of approximately 200 nm. Example 2
[0043] 1. Clean the ITO transparent conductive substrate with tap water, then sonicate it in an ultrasonic machine for 15 minutes each with isopropanol and acetone. Dry the liquid on the surface of the ITO substrate after sonication with a nitrogen gas gun, and then treat it with a UV ozone generator for 15 minutes.
[0044] 2. A layer of [(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (Me-4PACz) with a thickness of approximately 10 nm was prepared on an ITO substrate after UV ozone treatment as the first hole transport layer.
[0045] 3. A wide-bandgap perovskite layer with a thickness of approximately 350-400 nm is prepared on the substrate on which the first hole transport layer has been prepared.
[0046] 4. Prepare a C layer on a wide-bandgap perovskite layer. 60 As the first electron transport layer, it has a thickness of approximately 13 nm.
[0047] 5. Fabricate a quantum well tunneling junction on the first transport layer. Specifically, this is done by first fabricating a quantum well tunneling junction on the C1000-C ... 60 Prepare a layer of Phlm-doped C 60 Phlm, with a thickness of approximately 5 nm, and then on C 60 Prepare another layer of C on Phlm 60 The thickness is approximately 13 nm; then in C 60 A layer of MoO3 with a thickness of about 30 nm was prepared on the first layer, and then a layer of MoO3:Ce doped with Ce was prepared with a thickness of about 10 nm. Then, another layer of MoO3 with a thickness of about 30 nm was prepared on this first layer.
[0048] 6. A layer of PEDOT with a thickness of approximately 70 nm was fabricated on the quantum well tunneling junction as a second hole transport layer.
[0049] 7. A narrow bandgap perovskite layer with a thickness of approximately 800-2000 nm is prepared on the substrate of the second hole transport layer.
[0050] 8. Preparation of a fullerene (C) layer on a narrow bandgap perovskite layer 60 )+BCP serves as the second electron transport layer, where C 60 The thickness is approximately 26 nm, and the thickness of BCP is approximately 6 nm.
[0051] 9. Finally, a copper (Cu) layer was prepared as a metal electrode with a thickness of approximately 200 nm.
[0052] Figure 2The diagram shows the band structure of a conventional tunneling junction and a quantum well tunneling junction. In a conventional tunneling junction, electrons at the bottom of the conduction band of the electron transport layer and holes at the top of the valence band of the hole transport layer are very close to the Fermi level, so recombination of electrons and holes can occur near the tunneling junction. In a quantum well tunneling junction, due to the presence of the quantum well, electrons and holes are more easily bound in the quantum well structure, thus getting closer to the Fermi level, and therefore the recombination efficiency of electrons and holes is higher. Figure 4 The figure shown is a performance comparison chart of the all-perovskite tandem solar cells in Example 1 and Example 2. It can be seen that due to the use of quantum well tunnel junction, the electron-hole recombination efficiency is higher, and the open-circuit voltage, short-circuit current density and fill factor of the all-perovskite tandem solar cell are improved, and the photoelectric conversion efficiency is increased from 22% to 25%.
Claims
1. A fully perovskite tandem solar cell, comprising a transparent conductive substrate, a first sub-cell, a quantum well tunnel junction, a second sub-cell, and a back electrode arranged sequentially along the direction of sunlight incidence, characterized in that, The first sub-cell, the quantum well tunnel junction, and the second sub-cell are one of the following: (1) The first sub-cell includes a first hole transport layer, a first perovskite layer and a first electron transport layer arranged sequentially along the direction of sunlight incident; the second sub-cell includes a second hole transport layer, a second perovskite layer and a second electron transport layer arranged sequentially along the direction of sunlight incident; the quantum well tunnel junction includes a first n++ layer, a second n++ layer, a third n++ layer, a first p++ layer, a second p++ layer and a third p++ layer arranged sequentially along the direction of sunlight incident. Or (2) the first sub-cell includes a first electron transport layer, a first perovskite layer and a first hole transport layer arranged sequentially along the direction of sunlight incident, the second sub-cell includes a second electron transport layer, a second perovskite layer and a second hole transport layer arranged sequentially along the direction of sunlight incident, and the quantum well tunneling junction includes a first p++ layer, a second p++ layer, a third p++ layer, a first n++ layer, a second n++ layer and a third n++ layer arranged sequentially along the direction of sunlight incident; The thickness of the second n++ layer is less than the thickness of the first n++ layer and the third n++ layer; The thickness of the second p++ layer is less than the thickness of the first p++ layer and the third p++ layer.
2. The all-perovskite tandem solar cell according to claim 1, characterized in that, The first n++ layer and the third n++ layer are made of the same material, while the first n++ layer and the second n++ layer are made of different materials.
3. The all-perovskite tandem solar cell according to claim 2, characterized in that, The material of the first n++ layer is selected from C 60 C 70 The materials for the second n++ layer are graphene, PCBM, ICBA, Nb2O5, TiO2, SnO2, or ZnO; the materials for the second n++ layer are selected from undoped or doped C. 60 C 70 The dopant may be graphene, PCBM, ICBA, Nb2O5, TiO2, SnO2, or ZnO, wherein the dopant is selected from organic matter, metal ions, or atoms.
4. The all-perovskite tandem solar cell according to claim 1, characterized in that, The first p++ layer and the third p++ layer are made of the same material, while the first p++ layer and the second p++ layer are made of different materials.
5. The all-perovskite tandem solar cell according to claim 4, characterized in that, The material of the first p++ layer is selected from PVK, MeO-2PACz, 2PACz, Me-4PACz, CuI, spiro-TTB, NiO, MoO3, Cu2O, CuI, CuPc, CuSCN, graphene redox, PTAA, PEDOT:PSS, and Ploy-TPD; the material of the second p++ layer is selected from undoped or doped PVK, MeO-2PACz, 2PACz, Me-4PACz, CuI, spiro-TTB, NiO, MoO3, Cu2O, CuI, CuPc, CuSCN, graphene redox, PTAA, PEDOT:PSS, and Ploy-TPD, wherein the dopant is metal ions or atoms.
6. A solar energy module, characterized in that, Including the all-perovskite tandem solar cell according to any one of claims 1-5.