Solar cell substrate and solar cell

Abstract

The utility model relates to a solar cell substrate and a solar cell. The solar cell substrate comprises a supporting layer and a metal layer which are arranged in a stacked mode. And the metal layer contains metal vanadium. According to the solar cell substrate, the reaction activity of the vanadium metal layer and the perovskite is low, and the stability of the carrier transport layer and the perovskite layer is facilitated. The solar cell substrate provided by the utility model can further improve the sunlight absorption rate of a perovskite cell, thereby improving the photoelectric conversion efficiency of the cell. Meanwhile, metal has good ductility, so that the solar cell substrate is suitable for being applied to a flexible solar cell device.

Description

Technical Field

[0001] This utility model relates to the field of solar cell technology, and in particular to a solar cell substrate and a solar cell. Background Technology

[0002] Due to their low cost, aesthetic appeal, lightweight nature, and impressive photoelectric conversion efficiency, an increasing number of researchers are investing in the study of perovskite solar cells (PSCs). To date, the vast majority of PSCs are constructed on rigid glass substrates coated with transparent conductive oxides (TCOs), such as indium tin oxide (ITO) or fluorine-doped tin oxide (FTO). A very few PSCs are constructed on metal film substrates, such as Pb-Sn perovskite solar cells and all-perovskite tandem solar cells fabricated by evaporating copper films on glass, and inverted perovskite solar cells fabricated by inserting a layer of IZO onto molybdenum. However, copper and molybdenum metals can potentially react chemically with perovskite, which is detrimental to the stability of perovskite devices.

[0003] Therefore, it is necessary to develop a new type of substrate that does not react with perovskite to improve the stability of perovskite solar cells. Utility Model Content

[0004] Therefore, it is necessary to provide a solar cell substrate and a solar cell to address the problem that existing substrates react with perovskite thin films, thereby reducing the stability of perovskite cells.

[0005] A solar cell substrate includes a support layer and a metal layer stacked together; the metal layer contains vanadium.

[0006] In the aforementioned solar cell substrate, the vanadium metal layer exhibits low reactivity with the perovskite layer, which is beneficial to the stability of both the carrier transport layer and the perovskite layer. This novel solar cell substrate can further enhance the solar energy absorption rate of perovskite cells, thereby improving the photoelectric conversion efficiency. Furthermore, due to the good ductility of the metal, this solar cell substrate is suitable for application in flexible solar cell devices.

[0007] In one embodiment, the metal layer contains an alloy of metallic vanadium. The vanadium alloy includes, but is not limited to, vanadium-nickel alloys, vanadium-molybdenum alloys, vanadium-copper alloys, and vanadium-aluminum alloys.

[0008] In one embodiment, the metal layer is one of copper / vanadium composite film, molybdenum / vanadium composite film, silver / vanadium composite film, gold / vanadium composite film, vanadium / ITO, vanadium / AZO, vanadium / IWO, vanadium / BZO, vanadium / IZO, and vanadium\PEDOT:PSS (1000) composite film.

[0009] In one embodiment, the thickness of the metal layer is 50~300nm.

[0010] In one embodiment, the support layer is a glass layer, a stainless steel layer, a PET layer, a PEN layer, or a PI layer.

[0011] In one embodiment, the support layer is a glass layer.

[0012] In one embodiment, the thickness of the support layer is 1 to 3.2 mm.

[0013] In one embodiment, a transparent conductive layer is further included, which is disposed on the side of the metal layer away from the support layer.

[0014] In one embodiment, the thickness of the transparent conductive layer is 10~100nm.

[0015] In one embodiment, the transparent conductive layer contains a transparent conductive oxide. The solar cell substrate of this invention, by depositing a transparent conductive layer on top of a metal layer, can ensure energy level matching.

[0016] In one embodiment, the transparent conductive oxide includes at least one of indium tin oxide (ITO) and fluorine-doped tin dioxide (FTO).

[0017] In one embodiment, the solar cell substrate further includes a conductive layer disposed between the support layer and the metal layer; the conductive layer contains at least one of copper, silver, gold, and molybdenum.

[0018] In one embodiment, the thickness of the conductive layer is 10~200nm.

[0019] In one embodiment, the target material has a vanadium metal purity greater than 99%.

[0020] This invention also provides a solar cell, including the solar cell substrate described above.

[0021] In one embodiment, the solar cell is a perovskite solar cell.

[0022] In one embodiment, the solar cell includes the following structure stacked in sequence: a solar cell substrate, a first charge transport layer, a perovskite layer, a second charge transport layer, and an electrode layer as described above.

[0023] In one embodiment, the charge transport layer comprises at least one layer of p-type semiconductor material or n-type semiconductor material; the p-type semiconductor material includes one of NiOx, PTAA, PEDOT:PSS (4083), self-assembled small molecules, and polymeric self-assembled molecules.

[0024] In one embodiment, the polymeric self-assembled molecule contains an anchoring group, including at least one selected from carboxylic acid group, borate group, mercapto group, siloxane group, sulfonic acid group, o-diphenyl group, phenol, and silicate group; the n-type semiconductor includes SnO2, ZnO, TiO2, PCBM, and C. 60 At least one of them.

[0025] In one embodiment, the first charge transport layer and the second charge transport layer are either p-type or n-type semiconductor materials. That is, if the first charge transport layer is a p-type semiconductor material, then the second charge transport layer is an n-type semiconductor material, and vice versa.

[0026] In one embodiment, the perovskite material in the perovskite layer has an ABX3 structure, wherein A is at least one of methylamine, formamidinium, cesium, and rubidium, B is at least one of lead and tin, and X is at least one of chlorine, bromine, and iodine.

[0027] In one embodiment, the electrode layer contains at least one of ITO, IWO, IZO, AZO, and BZO.

[0028] In one embodiment, the first charge transport layer is a hole transport layer and the second charge transport layer is an electron transport layer.

[0029] This invention also provides a photovoltaic module, including the solar cell described above.

[0030] This invention also provides a stacked battery, including the solar cell described above.

[0031] This invention also provides a power generation device, including the solar cell described above.

[0032] This invention also provides an electrical device, including the solar cell described above.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention discloses a solar cell substrate and a solar cell. The vanadium metal layer exhibits low reactivity with the perovskite layer, which is beneficial to the stability of the carrier transport layer and the perovskite layer. This solar cell substrate further enhances the absorption rate of sunlight by the perovskite cell, thereby improving the photoelectric conversion efficiency. Simultaneously, due to the good ductility of the metal, this solar cell substrate is suitable for application in flexible solar cell devices. Furthermore, the addition of a transparent conductive layer on the metal layer ensures energy level matching. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of one structure of the solar cell substrate of this utility model;

[0036] Figure 2 This is a schematic diagram of one structure of the solar cell substrate of this utility model;

[0037] Figure 3 This is a schematic diagram of one structure of the solar cell substrate of this utility model;

[0038] Figure 4 This is a schematic diagram of the structure of the solar cell in this utility model.

[0039] Explanation of reference numerals in the attached figures: 1. Solar cell substrate; 11. Support layer; 12. Conductive layer; 13. Metal layer; 14. Transparent conductive layer; 2. Solar cell; 21. First charge transport layer; 22. Perovskite layer; 23. Second charge transport layer; 24. Electrode layer. Detailed Implementation

[0040] To facilitate understanding of this utility model, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of this utility model are shown in the drawings. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] Example 1

[0043] A solar cell substrate 1, such as Figure 1As shown, it includes a support layer 11 and a metal layer 13 stacked sequentially from bottom to top; the metal layer 13 contains vanadium and has a thickness of 50~300nm; the support layer 11 is a glass layer, stainless steel layer, PET layer, PEN layer or PI layer and has a thickness of 1~3.2mm.

[0044] Example 2

[0045] A solar cell substrate 1, such as Figure 2 As shown, the structure includes a support layer 11, a metal layer 13, and a transparent conductive layer 14 stacked sequentially from bottom to top. The support layer 11 is a glass layer, a stainless steel layer, a PET layer, a PEN layer, or a PI layer, and the thickness of the support layer 11 is 1~3.2 mm. The metal layer 13 contains vanadium metal and has a thickness of 50~300 nm. The transparent conductive layer 14 contains a transparent conductive oxide, which includes at least one of indium tin oxide (ITO) and fluorine-doped tin dioxide (FTO), and the thickness of the transparent conductive layer 14 is 10~100 nm.

[0046] Example 3

[0047] A solar cell substrate 1, such as Figure 3 As shown, the structure includes a support layer 11, a conductive layer 12, a metal layer 13, and a transparent conductive layer 14, which are stacked sequentially from bottom to top. The support layer 11 is a glass layer, a stainless steel layer, a PET layer, a PEN layer, or a PI layer, and the thickness of the support layer 11 is 1~3.2 mm. The conductive layer 12 contains at least one of copper, silver, gold, and molybdenum, and the thickness of the conductive layer 12 is 10~200 nm. The metal layer 13 contains vanadium and the thickness of the metal layer 13 is 50~300 nm. The transparent conductive layer 14 contains a transparent conductive oxide, which includes at least one of indium tin oxide (ITO) and fluorine-doped tin dioxide (FTO), and the thickness of the transparent conductive layer 14 is 10~100 nm.

[0048] Example 4

[0049] A solar cell substrate 1, such as Figure 1 As shown, it includes a support layer 11 and a metal layer 13 stacked sequentially from bottom to top; the support layer 11 is a glass layer, and the metal layer 13 is a vanadium metal layer (the vanadium metal target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%). The thickness of the support layer 11 is 2mm, and the thickness of the metal layer 13 is 130nm.

[0050] Example 5

[0051] A solar cell substrate 1, such as Figure 1As shown, it includes a support layer 11 and a metal layer 13 stacked sequentially from bottom to top; the support layer 11 is a glass layer, and the metal layer 13 is a vanadium metal layer (the vanadium metal target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%). The support layer 11 has a thickness of 2 mm, and the metal layer 13 has a thickness of 100 nm.

[0052] Example 6

[0053] A solar cell substrate 1, such as Figure 1 As shown, it includes a support layer 11 and a metal layer 13 stacked sequentially from bottom to top; the support layer 11 is a glass layer, and the metal layer 13 is a vanadium metal layer (the vanadium metal target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%). The support layer 11 has a thickness of 2 mm, and the metal layer 13 has a thickness of 80 nm.

[0054] Example 7

[0055] A solar cell substrate 1, such as Figure 2 As shown, the structure includes a support layer 11, a metal layer 13, and a transparent conductive layer 14, which are stacked sequentially from bottom to top. The support layer 11 is a glass layer, the metal layer 13 is a vanadium metal layer (the vanadium metal target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%), and the transparent conductive layer 14 is an indium tin oxide layer. The thickness of the support layer 11 is 2 mm, the thickness of the metal layer 13 is 130 nm, and the thickness of the transparent conductive layer 14 is 40~50 nm.

[0056] Example 8

[0057] A solar cell substrate 1, such as Figure 2 As shown, the structure includes a support layer 11, a metal layer 13, and a transparent conductive layer 14, which are stacked sequentially from bottom to top. The support layer 11 is a glass layer, the metal layer 13 is a vanadium metal layer (the vanadium metal target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%), and the transparent conductive layer 14 is an indium tin oxide layer. The thickness of the support layer 11 is 2 mm, the thickness of the metal layer 13 is 100 nm, and the thickness of the transparent conductive layer 14 is 40~50 nm.

[0058] Example 9

[0059] A solar cell substrate 1, such as Figure 2 As shown, the structure includes a support layer 11, a metal layer 13, and a transparent conductive layer 14 stacked sequentially from bottom to top. The support layer 11 is a glass layer, the metal layer 13 is a vanadium metal layer (the vanadium metal target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%), and the transparent conductive layer 14 is an indium tin oxide layer. The thickness of the support layer 11 is 2 mm, the thickness of the metal layer 13 is 80 nm, and the thickness of the transparent conductive layer 14 is 40~50 nm.

[0060] Example 10

[0061] A solar cell 2, such as Figure 4 As shown, the structure includes the following layers stacked sequentially from bottom to top: a solar cell substrate 1, a first charge transport layer 21, a perovskite layer 22, a second charge transport layer 23, and an electrode layer 24. The first charge transport layer 21 is a hole transport layer, and the second charge transport layer 23 is an electron transport layer. The first charge transport layer 21 contains PTAA, and the second charge transport layer 23 contains C. 60 At least one of tin oxide and perovskite, the perovskite in perovskite layer 22 has the structural formula Cs 0.05 FA 0.83 MA 0.12 PbI 2.6 Br 0.4 Electrode layer 24 is a composite electrode of indium tin oxide and metallic silver.

[0062] Example 11

[0063] A solar cell 2, such as Figure 4 As shown, the structure includes the following layers stacked sequentially from bottom to top: a solar cell substrate 1, a first charge transport layer 21, a perovskite layer 22, a second charge transport layer 23, and an electrode layer 24. The first charge transport layer 21 is a PTAA hole transport layer, and the perovskite in the perovskite layer 22 has the structural formula Cs. 0.05 FA 0.83 MA 0.12 PbI 2.6 Br 0.4 The second charge transport layer 23 is an electron transport layer, which is a C layer with a thickness of 20 nm. 60 and The solar cell substrate 1 consists of a 30nm thick SnO2 phase composite layer and an electrode layer 24, which is a 40nm thick indium tin oxide and a 150nm thick elemental silver phase composite electrode. The substrate includes a support layer 11 and a metal layer 13 stacked sequentially from bottom to top. The support layer 11 is a glass layer, and the metal layer 13 is a vanadium metal layer (the vanadium target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%). The support layer 11 is 2mm thick, and the metal layer 13 is 130nm thick.

[0064] Example 12

[0065] A solar cell 2, such as Figure 4 As shown, the structure includes the following layers stacked sequentially from bottom to top: a solar cell substrate 1, a first charge transport layer 21, a perovskite layer 22, a second charge transport layer 23, and an electrode layer 24. The first charge transport layer 21 is a PTAA hole transport layer, and the perovskite in the perovskite layer 22 has the structural formula Cs. 0.05FA 0.83 MA 0.12 PbI 2.6 Br 0.4 The second charge transport layer 23 is an electron transport layer, which is a C layer with a thickness of 20 nm. 60 and The solar cell substrate 1 consists of a 30nm thick SnO2 phase composite layer and an electrode layer 24, which is a 40nm thick indium tin oxide and a 150nm thick elemental silver phase composite electrode. The substrate 1 comprises a support layer 11 and a metal layer 13 stacked sequentially from bottom to top. The support layer 11 is a glass layer, and the metal layer 13 is a vanadium metal layer (the vanadium metal target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%). The support layer 11 has a thickness of 2mm, and the metal layer 13 has a thickness of 100nm.

[0066] Example 13

[0067] A solar cell 2, such as Figure 4 As shown, the structure includes the following layers stacked sequentially from bottom to top: a solar cell substrate 1, a first charge transport layer 21, a perovskite layer 22, a second charge transport layer 23, and an electrode layer 24. The first charge transport layer 21 is a PTAA hole transport layer, and the perovskite in the perovskite layer 22 has the structural formula Cs. 0.05 FA 0.83 MA 0.12 PbI 2.6 Br 0.4 The second charge transport layer 23 is an electron transport layer, which is a C layer with a thickness of 20 nm. 60 and The solar cell substrate 1 consists of a 30nm thick SnO2 phase composite layer and an electrode layer 24, which is a 40nm thick indium tin oxide and a 150nm thick elemental silver phase composite electrode. The substrate includes a support layer 11 and a metal layer 13 stacked sequentially from bottom to top. The support layer 11 is a glass layer, and the metal layer 13 is a vanadium metal layer (the vanadium target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%). The support layer 11 is 2mm thick, and the metal layer 13 is 80nm thick.

[0068] Example 14

[0069] A solar cell 2, such as Figure 4 As shown, the structure includes the following layers stacked sequentially from bottom to top: a solar cell substrate 1, a first charge transport layer 21, a perovskite layer 22, a second charge transport layer 23, and an electrode layer 24. The first charge transport layer 21 is a PTAA hole transport layer, and the perovskite in the perovskite layer 22 has the structural formula Cs. 0.05 FA 0.83 MA 0.12 PbI2.6 Br 0.4 The second charge transport layer 23 is an electron transport layer, which is a C layer with a thickness of 20 nm. 60 and The solar cell substrate 1 comprises a 30 nm thick SnO2 phase composite layer, and an electrode layer 24 consisting of a 40 nm thick indium tin oxide and a 150 nm thick elemental silver phase composite electrode. The substrate 1 includes a support layer 11, a metal layer 13, and a transparent conductive layer 14, stacked sequentially from bottom to top. The support layer 11 is a glass layer, the metal layer 13 is a vanadium metal layer (the vanadium target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%), and the transparent conductive layer 14 is an indium tin oxide layer. The support layer 11 has a thickness of 2 mm, the metal layer 13 has a thickness of 130 nm, and the transparent conductive layer 14 has a thickness of 40-50 nm.

[0070] Example 15

[0071] A solar cell 2, such as Figure 4 As shown, the structure includes the following layers stacked sequentially from bottom to top: a solar cell substrate 1, a first charge transport layer 21, a perovskite layer 22, a second charge transport layer 23, and an electrode layer 24. The first charge transport layer 21 is a PTAA hole transport layer, and the perovskite in the perovskite layer 22 has the structural formula Cs. 0.05 FA 0.83 MA 0.12 PbI 2.6 Br 0.4 The second charge transport layer 23 is an electron transport layer, which is a C layer with a thickness of 20 nm. 60 and The solar cell substrate 1 comprises a 30 nm thick SnO2 phase composite layer, and an electrode layer 24 consisting of a 40 nm thick indium tin oxide and a 150 nm thick elemental silver phase composite electrode. The substrate 1 includes a support layer 11, a metal layer 13, and a transparent conductive layer 14, stacked sequentially from bottom to top. The support layer 11 is a glass layer, the metal layer 13 is a vanadium metal layer (the vanadium target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%), and the transparent conductive layer 14 is an indium tin oxide layer. The support layer 11 has a thickness of 2 mm, the metal layer 13 has a thickness of 100 nm, and the transparent conductive layer 14 has a thickness of 40-50 nm.

[0072] Example 16

[0073] A solar cell 2, such as Figure 4 As shown, the structure includes the following layers stacked sequentially from bottom to top: a solar cell substrate 1, a first charge transport layer 21, a perovskite layer 22, a second charge transport layer 23, and an electrode layer 24. The first charge transport layer 21 is a PTAA hole transport layer, and the perovskite in the perovskite layer 22 has the structural formula Cs.0.05 FA 0.83 MA 0.12 PbI 2.6 Br 0.4 The second charge transport layer 23 is an electron transport layer, which is a C layer with a thickness of 20 nm. 60 and The solar cell substrate 1 comprises a 30 nm thick SnO2 phase composite layer, and an electrode layer 24 consisting of a 40 nm thick indium tin oxide and a 150 nm thick elemental silver phase composite electrode. The substrate 1 includes a support layer 11, a metal layer 13, and a transparent conductive layer 14, stacked sequentially from bottom to top. The support layer 11 is a glass layer, the metal layer 13 is a vanadium metal layer (the vanadium target was purchased from Zhongnuo New Materials, CAS7440-62-2, purity 99.9%), and the transparent conductive layer 14 is an indium tin oxide layer. The support layer 11 has a thickness of 2 mm, the metal layer 13 has a thickness of 80 nm, and the transparent conductive layer 14 has a thickness of 40-50 nm.

[0074] Experimental Example

[0075] A solar simulator was used to test the solar cells 2 of Examples 11-16 and the control group solar cells (both with an effective area of ​​0.142 cm²). 2 Performance tests were conducted on open-circuit voltage, short-circuit current density, fill factor, and energy conversion efficiency, with the calibrated light intensity set at 1000 W / m². 2 .

[0076] Control Group 1: A solar cell comprising, from bottom to top, the following structure stacked sequentially: a solar cell substrate, a first charge transport layer, a perovskite layer, a second charge transport layer, and an electrode layer. The first charge transport layer is a PTAA hole transport layer, and the perovskite in the perovskite layer has the structural formula Cs. 0.05 FA 0.83 MA 0.12 PbI 2.6 Br 0.4 The second charge transport layer is an electron transport layer, which is a 20nm thick C layer. 60 and The solar cell substrate consists of a 30 nm thick SnO2 phase composite layer and an electrode layer consisting of a 40 nm thick indium tin oxide and a 150 nm thick elemental silver phase composite electrode. The substrate comprises a support layer and a metal layer stacked sequentially from bottom to top; the support layer is a glass layer, and the metal layer is a molybdenum metal layer. The support layer has a thickness of 2 mm, and the metal layer has a thickness of 130 nm.

[0077] Control Group 2: A solar cell comprising, from bottom to top, the following structure stacked sequentially: a solar cell substrate, a first charge transport layer, a perovskite layer, a second charge transport layer, and an electrode layer. The first charge transport layer is a PTAA hole transport layer, and the perovskite in the perovskite layer has the structural formula Cs. 0.05 FA 0.83 MA 0.12 PbI 2.6 Br 0.4 The second charge transport layer is an electron transport layer, which is a 20nm thick C layer. 60 and The solar cell substrate consists of a 30 nm thick SnO2 phase composite layer and an electrode layer composed of a 40 nm thick indium tin oxide and a 150 nm thick elemental silver phase composite electrode. The substrate comprises a support layer and a metal layer stacked sequentially from bottom to top; the support layer is a glass layer, and the metal layer is a copper metal layer. The support layer has a thickness of 2 mm, and the metal layer has a thickness of 130 nm.

[0078] The test results are shown in Table 1. The solar cell 2 in Example 15 has the highest conversion efficiency.

[0079]

[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A solar cell substrate, characterized in that: The material comprises a support layer (11), a metal layer (13), and a transparent conductive layer (14) stacked sequentially from bottom to top. The support layer (11) is a glass layer, the metal layer (13) is a vanadium metal layer, and the thickness of the metal layer (13) is 80 nm, 100 nm, or 130 nm. The transparent conductive layer (14) is an indium tin oxide layer, and the thickness of the transparent conductive layer (14) is 40-50 nm. The thickness of the support layer (11) is 2 mm.

2. A solar cell, characterized in that: This includes the following structures stacked sequentially from bottom to top: The solar cell substrate, first charge transport layer (21), perovskite layer (22), second charge transport layer (23), and electrode layer (24) as described in claim 1, wherein the first charge transport layer (21) is a PTAA hole transport layer; and the perovskite structure in the perovskite layer (22) is Cs 0.05 FA 0.83 MA 0.12 PbI 2.6 Br 0.4 The second charge transport layer (23) is an electron transport layer, and the electron transport layer is a C material with a thickness of 20 nm. 60 The electrode layer (24) is a composite electrode consisting of a 40 nm thick indium tin oxide layer and a 150 nm thick elemental silver layer superimposed on a SnO2 layer.

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