Stacked solar cell

Abstract

The present application discloses a stacked solar cell. The stacked solar cell includes a light absorbing layer group and a heterojunction layer group. The light absorbing layer group includes an excitation layer, a first electron transport layer group disposed on a first side of the excitation layer, and a first hole transport layer group disposed on a second side of the excitation layer. The first side of the heterojunction layer group is a second electron transport layer that contacts the first hole transport layer group, and the second side of the heterojunction layer group is a second hole transport layer. The heterojunction layer group has the effect of amplifying the number of hole-electron pairs generated by excitation of the light absorbing layer group, thereby significantly improving the efficiency of the stacked solar cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic power generation, and particularly to a stacked solar cell.

Background Art

[0002] A solar cell is a photovoltaic semiconductor sheet that directly generates electricity using sunlight. The basic principle of a solar cell is that sunlight irradiates a semiconductor p-n junction, forming hole-electron pairs, and due to the action of the electric field constructed within the p-n junction, the holes generated by light flow to the p region, the electrons generated by light flow to the n region, and when a circuit is connected, an electric current is generated. Currently, the conversion efficiency of solar cells is low and improvement is needed.

Summary of the Invention

[0003] To solve the above problems, the present invention proposes a stacked solar cell. This stacked solar cell includes a light absorption layer group and a heterojunction layer group. The light absorption layer group includes an excitation layer, a first electron transport layer group disposed on a first side surface of the excitation layer, and a first hole transport layer group disposed on a second side surface of the excitation layer. The first side surface of the heterojunction layer group is a second electron transport layer, which is in contact with the first hole transport layer group. The second side surface of the heterojunction layer group is a second hole transport layer. Upon irradiation with sunlight, both the excitation layer and the heterojunction layer group are excited, and the electrons generated in the excitation layer are transported out of the stacked solar cell through the first electron transport layer. The holes generated in the excitation layer flow through the first hole transport layer group to the heterojunction layer group and recombine with the electrons generated in the heterojunction layer group. The holes generated in the heterojunction layer group are transported out of the stacked solar cell from the second hole transport layer.

[0004] In one embodiment, the first hole transport layer group includes a hole transport layer in contact with the excitation layer, a PN junction in contact with the hole transport layer, and a first light transport layer in contact with the PN junction. The first light transport layer is in contact with the second electron transport layer, and the refractive index of the first light transport layer is smaller than the refractive index of the second electron transport layer.

[0005] In one embodiment, the refractive index of the first light transport layer is between 1.15 and 1.35, and the thickness is between 50 nm and 200 nm. The refractive index of the second electron transport layer is between 3.5 and 4.2, and the thickness is between 0 and 30 nm.

[0006] In one embodiment, the first light transport layer includes a first conductive layer in contact with the PN junction, a first protective layer in contact with the first conductive layer, a second conductive layer in contact with the first protective layer, a second protective layer in contact with the second conductive layer, and a light emitting layer in contact with the second protective layer. The first conductive layer has a first refractive index n1 and a first thickness d1, the first protective layer has a second refractive index n2 and a second thickness d2, the second conductive layer has a third refractive index n3 and a third thickness d3, the second protective layer has a fourth refractive index n4 and a fourth thickness d4, and the light emitting layer has a fifth refractive index n5 and a fifth thickness d5. n1 is between 1.8 and 2.1, d1 is between 20 nm and 80 nm, n2 is between 0.1 and 5, d2 is between 0.5 nm and 10 nm, n3 is between 0.1 and 1.5, d3 is between 5 nm and 50 nm, n4 is between 1.3 and 2.1, d4 is between 0.5 nm and 25 nm, and n5 is between 1.4 and 2.4, d5 is between 20 nm and 80 nm.

[0007] In one embodiment, the first conductive layer includes a conductive metal oxide, the first protective layer includes one of a metal, a conductive metal oxide, and a conductive metal nitride, the second conductive layer includes a conductive material and a metal oxide and / or a metal nitride, the second protective layer includes one of a non-metal oxide, a metal nitride, and a metal oxide, and the light emitting layer includes one of a non-metal oxide, nitride, sulfide, fluoride, and carbide.

[0008] In one embodiment, the material of the first conductive layer is one selected from In2O3, SnO2, ZnO, ITO, AZO, IZO, ITiO, IZTO, and FTO. The material of the first protective layer is one selected from Si, Ti, Al, Ni, Cr, NiCr, TiN, ZnO, TiO2, SnO2, SiO2, Nb2O5, Ta2O5, and Si3N4. The conductive material of the second conductive layer is one selected from Ag, Cu, Al, Mo, Ag alloy, Cu alloy, Al alloy, and Mo alloy, and further includes inclusions formed of oxides and / or nitrides of the conductive material of the second conductive layer. The material of the second protective layer is one selected from TiN, ZnO, TiO2, SnO2, SiO2, Si3N4, AZO, IZO, and YZO. The material of the light-emitting layer is one selected from TiO2, SnO2, ZnO, Nb2O5, Ta2O5, Si3N4, ZnS, SiO2, Al2O3, MgF, MgS, SiC, AZO, GZO, and YZO.

[0009] In one embodiment, the hetero-junction layer group includes an N-type Si wafer, a first intrinsic amorphous silicon layer located on the first surface of the N-type Si wafer and doped with oxygen, an N-type amorphous silicon layer located on the first intrinsic amorphous silicon layer and forming the second electron transport layer, a second intrinsic amorphous silicon layer located on the second surface of the N-type Si wafer and the same as the first intrinsic amorphous silicon layer, and a P-type amorphous silicon layer located on the second intrinsic amorphous silicon layer and forming the second hole transport layer.

[0010] In one embodiment, in the first intrinsic amorphous silicon layer, the oxygen content is between 0 and 30 wt%.

[0011] In one embodiment, a second light transport layer is further provided outside the P-type amorphous silicon layer. The second light transport layer is the same as the first light transport layer. The refractive index of the P-type amorphous silicon layer is between 3.2 and 3.8, and the thickness is between 0 and 60 nm.

[0012] In one embodiment, the PN junction includes an N-type nanosilicon layer in contact with the first light transport layer and a P-type nanosilicon layer located on the N-type nanosilicon layer, and the P-type nanosilicon layer is in contact with the hole transport layer.

[0013] In one embodiment, the first electron transport layer group includes an electron transport layer in contact with the excitation layer and a conductive layer in contact with the electron transport layer.

[0014] In one embodiment, the material of the conductive layer is In2O3, and the dopant is one or more of Ga2O3, ZnO2, CeO2, TiO2, Mo2O3, ZrO2, and WO2. The weight content of In2O3 is between 80wt% and 100wt%, and the remaining part is the dopant and inevitable impurities. Alternatively, the material of the conductive layer is ZnO, and the dopant is one or more of SnO2, Al2O3, Ga2O3, and B2O3. The weight content of ZnO is between 80wt% and 100wt%, and the remaining part is the dopant and inevitable impurities.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows. In the stacked solar cell of the present application, the heterojunction layer group has the effect of amplifying the number of hole-electron pairs generated by the excitation of the light absorption layer group, thereby greatly improving the efficiency of the stacked solar cell.

Brief Description of the Drawings

[0016] The drawings described herein are used to provide a further understanding of the present application, form a part of the present application, and the exemplary embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an inappropriate limitation of the present application. In the drawings,

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0017] To further clarify the purpose, technical solution, and advantages of this application, hereinafter, with reference to specific embodiments of this application and the corresponding attached drawings, the technical solutions of the embodiments of this application will be clearly and completely described. Naturally, the embodiments described herein are only a part, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative work should be included within the protection scope of this application.

[0018] FIG. 1 schematically shows the structure of a stacked solar cell 1 according to an embodiment of this application. As shown in FIG. 1, the stacked solar cell 1 includes a light absorption layer group 10 and a heterojunction layer group 20 located inside the light absorption layer group 10 (i.e., in the direction away from the external environment) and in contact therewith. The light absorption layer group 10 includes an excitation layer 11, a first electron transport layer group 12 disposed on the first side surface of the excitation layer 11, and a first hole transport layer group 13 disposed on the second side surface of the excitation layer 11. The first side surface of the heterojunction layer group 20 is a second electron transport layer 203, which is in contact with the first hole transport layer group 13. The second side surface of the heterojunction layer group 20 is a second hole transport layer 205.

[0019] In such a stacked solar cell 1, both the excitation layer 11 and the heterojunction layer group 20 are excited by the irradiation of sunlight. The electrons generated in the excitation layer 11 are transported out of the stacked solar cell 1 through the first electron transport layer 12. The holes generated in the excitation layer 11 flow through the first hole transport layer group 13 to the heterojunction layer group 20 and recombine with the electrons generated in the heterojunction layer group 20. The holes generated in the heterojunction layer group 20 are transported out of the stacked solar cell 1 from the second hole transport layer 205. In this way, the heterojunction layer group 20 has the effect of amplifying the number of hole-electron pairs generated by the excitation of the light absorption layer group 10, thereby greatly improving the efficiency of the stacked solar cell 1.

[0020] In one embodiment, the first hole transport layer group 13 includes a hole transport layer 40 in contact with the excitation layer 11, a PN junction 42 in contact with the hole transport layer 40, and a first light transport layer 41 in contact with the PN junction 42. The first light transport layer 41 is in contact with the second electron transport layer 203, and the refractive index of the first light transport layer 41 is smaller than the refractive index of the second electron transport layer 203. The inventor has found that the PN junction 42 is also excited under sunlight irradiation, further amplifying the number of hole-electron pairs generated by the excitation of the light absorption layer group 10, thereby further improving the efficiency of the stacked solar cell 1. Also, since the refractive index of the first light transport layer 41 is smaller than the refractive index of the second electron transport layer 203, an antireflection layer is formed. As a result, the interior of the stacked solar cell 1 is irradiated with as much solar energy as possible (i.e., the hetero-junction layer group 20 is irradiated with more sunlight), making it easier for the hetero-junction layer group 20 to be excited and improving the efficiency of the stacked solar cell 1.

[0021] In one embodiment, the refractive index of the first light transport layer 41 is between 1.15 and 1.35, and the thickness is between 50 nm and 200 nm, and the refractive index of the second electron transport layer 203 is between 3.5 and 4.2, and the thickness is between 0 and 30 nm. It should be understood that in this application, the thickness of the second electron transport layer 203 is not equal to zero and is greater than zero. The inventor has found that by setting the first light transport layer 41 and the second electron transport layer 203 within this parameter range, sunlight can be more effectively incident on the interior of the stacked solar cell 1, which helps to improve the efficiency of the stacked solar cell 1.

[0022] As shown in FIG. 2, the first light transport layer 41 includes a first conductive layer 410 in contact with the PN junction 42, a first protective layer 411 in contact with the first conductive layer 410, a second conductive layer 412 in contact with the first protective layer 411, a second protective layer 413 in contact with the second conductive layer 412, and a light emitting layer 414 in contact with the second protective layer 413. That is, the first conductive layer 410, the first protective layer 411, the second conductive layer 412, the second protective layer 413, and the light emitting layer 414 are stacked and arranged, and the first conductive layer 410 is electrically connected to the PN junction 42, and the light emitting layer 414 is in contact with the hetero-junction layer group 20.

[0023] The first conductive layer 410 has a first refractive index n1 and a first thickness d1, the first protective layer 411 has a second refractive index n2 and a second thickness d2, the second conductive layer 412 has a third refractive index n3 and a third thickness d3, the second protective layer 413 has a fourth refractive index n4 and a fourth thickness d4, and the light emitting layer 414 has a fifth refractive index n5 and a fifth thickness d5. Here, n1 is between 1.8 and 2.1, and d1 is between 20 nm and 80 nm. n2 is between 0.1 and 5, and d2 is between 0.5 nm and 10 nm. n3 is between 0.1 and 1.5, and d3 is between 5 nm and 50 nm. n4 is between 1.3 and 2.1, and d4 is between 0.5 nm and 25 nm. n5 is between 1.4 and 2.4, and d5 is between 20 nm and 80 nm. The inventor has found that by configuring the first light transport layer 41 with these sub-layers, the refractive index of the first light transport layer 41 can be easily adjusted between 1.15 and 1.35 while maintaining the thickness of the first light transport layer 41 between 50 nm and 200 nm. In this way, sunlight is more effectively irradiated inside the stacked solar cell 1, and the efficiency of the stacked solar cell 1 is improved.

[0024] It should be understood that the number of sub-layers of the first light transport layer 41 may be more or less (even one layer) as long as its thickness and refractive index meet the requirements, but this will not be explained again here.

[0025] The first conductive layer 410 contains a conductive metal oxide. For example, the material of the first conductive layer 410 is one selected from In2O3, SnO2, ZnO, ITO, AZO, IZO, ITiO, IZTO, and FTO. In the case of ITO, the Sn2O doping weight percentage is greater than 0 and less than or equal to 50%. In the case of IZO, the ZnO doping weight percentage is greater than 0 and less than or equal to 50%. In the case of AZO, the Al2O3 doping weight percentage is greater than 0 and less than or equal to 50%. In the case of ITiO, the TiO2 doping weight percentage is greater than 0 and less than or equal to 10%. In the case of IZTO, the TiO2 doping weight percentage is greater than 0 and less than or equal to 10%, and the ZnO doping weight percentage is greater than 0 and less than or equal to 40%. In the case of FTO, the F doping weight percentage is greater than 0 and less than or equal to 10%. The inventor has found that using the above materials can not only achieve the required refractive index, but also have good conductivity, reduce resistance, and contribute to the improvement of the efficiency of the stacked solar cell 1.

[0026] The first protective layer 411 contains one of a metal, a conductive metal oxide, and a conductive metal nitride. For example, the metal may be one of Si, Ti, Al, Ni, Cr, and NiCr. The metal oxide may be one of ZnO, TiO2, SnO2, SiO2, Nb2O5, and Ta2O5. The metal nitride may be one of TiN and Si3N4. The inventor has found that when these materials are selected as the first protective layer 411, not only can the required refractive index be achieved, but also good antioxidation characteristics are provided, thereby preventing oxygen molecules from penetrating into the second conductive layer 412 and ensuring that the second conductive layer 412 has good conductivity. Also, since the thickness of the first protective layer 411 is relatively thin, the metal oxide or metal nitride also has good conductivity due to the quantum tunneling effect and contributes to the improvement of the efficiency of the stacked solar cell 1.

[0027] The second conductive layer 412 includes a conductive material and inclusions of inevitable metal oxides and / or metal nitrides. For example, the conductive material is one selected from Ag, Cu, Al, Mo, Ag alloys, Cu alloys, Al alloys, and Mo alloys. In a specific embodiment, in the Ag alloy layer, the weight ratio of Ag is greater than 50%, and the remaining 50% may be one of metal elements such as Zn, Cu, In, Pt, Pd, Au, Nb, Nd, B, Bi, Ni, etc. In the Cu alloy, the weight ratio of Cu is greater than 50%, and the remaining 50% may be one of metal elements such as Zn, Ag, In, Pt, Pd, Au, Nb, Nd, B, Bi, Ni, etc. In the Mo alloy layer, the weight ratio of Mo is greater than 80%, and the remaining 20% may be one of metal elements such as Zn, Cu, In, Pt, Pd, Au, Nb, Nd, B, Bi, Ni, etc. In the Al alloy layer, the weight ratio of Al is greater than 80%, and the remaining 20% may be one of metal elements such as Zn, Cu, In, Pt, Pd, Au, Nb, Nd, B, Bi, Ni, etc. The inclusions of metal oxides and / or metal nitrides are formed by introducing a small amount of oxygen and nitrogen during the coating process of the metal target material to oxidize and nitride the metal or alloy. These metals or alloys have good electrical conductivity, and even if they contain a small amount of inclusions of metal oxides and / or nitrides, the electrical conductivity of the entire second conductive layer 412 will not decrease. Also, these metal oxides and metal nitrides also improve the light transmittance of the second conductive layer 412. This is helpful for improving the efficiency of the stacked solar cell 1.

[0028] The second protective layer 413 includes one of non-metal oxides, metal nitrides, and metal oxides. For example, the non-metal oxides, metal nitrides, and metal oxides may be TiN, ZnO, TiO2, SnO2, SiO2, Si3N4. The second protective layer 413 formed by these compounds has good weather resistance and good waterproofness, and improves the protective effect on the second conductive layer 412. Since the thickness of the second protective layer 413 is relatively thin, the non-metal oxides, metal nitrides, and metal oxides also have relatively good electrical conductivity due to the quantum tunneling effect. As a result, the second protective layer 413 has relatively good electrical conductivity, which is helpful for improving the efficiency of the stacked solar cell 1.

[0029] The light emitting layer 414 contains one of non-metallic oxides, nitrides, sulfides, fluorides, and carbides. For example, the material of the light emitting layer 414 is selected from TiO2, SnO2, ZnO, Nb2O5, Ta2O5, Si3N4, ZnS, SiO2, Al2O3, MgF, MgS, SiC, AZO, GZO, and YZO. The refractive indices of these materials are relatively high, which helps to meet the refractive index requirements of the light extraction layer 200. Also, due to the quantum tunneling effect, these compounds also have appropriate conductivity, which can reduce the resistance of the light emitting layer 414 (and the light extraction layer 200), contributing to the improvement of the efficiency of the stacked solar cell 1.

[0030] Also, as shown in FIG. 1, the PN junction 42 includes an N-type nanosilicon layer 420 in contact with the first light transport layer 41 and a P-type nanosilicon layer 421 located on the N-type nanosilicon layer 420, and the P-type nanosilicon layer 421 is in contact with the hole transport layer 40. The inventor has found that the PN junction 42 not only amplifies the excitation effect on the excitation layer 11 but also effectively reduces the interface resistance, thus contributing to the improvement of the efficiency of the stacked solar cell 1.

[0031] Furthermore, as shown in FIG. 1, the heterojunction layer group 20 includes an N-type Si wafer 201, a first intrinsic amorphous silicon layer 202 doped with oxygen and located on the first surface of the N-type Si wafer 201, an N-type amorphous silicon layer 203 located on the first intrinsic amorphous silicon layer 202 and forming the aforementioned second electron transport layer 203, a second intrinsic amorphous silicon layer 204 located on the second surface of the N-type Si wafer 201 and identical to the first intrinsic amorphous silicon layer 201, and a P-type amorphous silicon layer 205 located on the second intrinsic amorphous silicon layer 204 and forming the second hole transport layer 205. In addition, the inventor has found that in this heterojunction layer group 20, since the semiconductor layer groups located on both sides of the N-type Si wafer 201 can be excited, the photoexcitation efficiency of the heterojunction layer group 20 is relatively high, thereby further improving the amplification of the photoexcitation effect of the light absorption layer group 10 and further improving the efficiency of the stacked solar cell 1. Furthermore, the inventor has found that doping oxygen into the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204 can further increase the light transmittance of the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204, which is more helpful for improving the excitation effect of the heterojunction layer group 20, thereby further improving the efficiency of the stacked solar cell 1.

[0032] In a specific embodiment, in the first intrinsic amorphous silicon layer 202, the oxygen content is between 0 and 30 wt%. It should be noted that in the first intrinsic amorphous silicon layer 202, the oxygen content is greater than zero. The inventor has found that at this oxygen doping concentration, not only the light transmittance of the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204 is improved, but also Si is not completely synthesized into SiO2. As a result, the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204 still have a high electron / hole transport effect, and the efficiency of the stacked solar cell 1 is further improved.

[0033] Also, as shown in FIG. 1, a second light transport layer 30 is further provided outside the P-type amorphous silicon layer 205, and the second light transport layer is the same as the first light transport layer 41. The refractive index of the P-type amorphous silicon layer 205 is between 3.2 and 3.8, and the thickness is between 0 and 60 nm. Note that the thickness of the P-type amorphous silicon layer 205 is greater than zero. In such a structure, the second light transport layer 30 and the P-type amorphous silicon layer 205 (i.e., the second hole transport layer 205) are also formed as an antireflection layer, which helps sunlight to enter and be excited inside the heterojunction layer group 20, thereby contributing to the improvement of the efficiency of the stacked solar cell 1.

[0034] The first electron transport layer group 12 includes an electron transport layer 120 in contact with the excitation layer 11 and a conductive layer 121 in contact with the electron transport layer 120. In a specific embodiment, the material of the conductive layer 121 is In2O3, and the dopant is one or more of Ga2O3, ZnO2, CeO2, TiO2, Mo2O3, ZrO2, and WO2. The weight content of In2O3 is between 80 wt% and 100 wt%, and the remaining part is the dopant and inevitable impurities. Alternatively, the material of the conductive layer 121 is ZnO, and the dopant is one or more of SnO2, Al2O3, Ga2O3, and B2O3. The weight content of ZnO is between 80 wt% and 100 wt%, and the remaining part is the dopant and inevitable impurities. Compared with ITO used in the prior art, the material of the conductive layer 121 in the present application not only has better light transmittance but also better conductivity, which helps to further improve the efficiency of the stacked solar cell 1.

[0035] It should be understood that a first metal electrode layer 50 is provided outside the conductive layer 121, and a second metal electrode layer 60 is provided outside the second light transport layer 30. The first electrode layer 50 and the second electrode layer 60 are used to conduct electricity in communication with an external wire, but this will not be described again here. 〈Example 1〉

[0036] Regarding the light absorption layer 10, the excitation layer 11 is a perovskite photosensitive layer FAPbI3. The electron transport layer 120 is SnO, and its thickness is 20 nm. The conductive layer 121 is IMO (i.e., In2O3 is doped with Mo2O3, and the content of In2O3 is 95 wt%), and the hole transport layer 40 is NiO.

[0037] Regarding the PN junction 42, the thickness of the P-type nanosilicon layer 421 is 22 nm, and the thickness of the N-type nanosilicon layer 420 is 28 nm.

[0038] Regarding the light transport layer, the first light transport layer 41 and the second light transport layer 30 are the same. The first conductive layer 410 is IZO, with a thickness of 45 nm and a refractive index of 2.0. The first protective layer 411 is Ti, with a thickness of 1 nm and a refractive index of 1.9. The second conductive layer 412 is a mixture of AgIn and AgInO x with a thickness of 8 nm and a refractive index of 0.3. The second protective layer 413 is ZnO, with a thickness of 15 nm and a refractive index of 2.0. The light emitting layer 414 is MgF, with a thickness of 60 nm and a refractive index of 1.45.

[0039] Regarding the heterojunction layer group 20, the thickness of the N-type Si wafer 201 is 0.2 mm. In the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204, the oxygen content is 25 wt% and the thickness is 10 nm. The thickness of the N-type amorphous silicon layer 203 is 10 nm, and the thickness of the P-type amorphous silicon layer 205 is 10 nm.

[0040] The first metal electrode layer 50 is Ag paste, and the second metal electrode layer 60 is Ag paste.

[0041] The efficiency of the stacked solar cell of Example 1 is shown in Table 1. 〈Example 2〉

[0042] Regarding the light absorption layer 10, the excitation layer 11 is a perovskite photosensitive layer FAPbI3. The electron transport layer 120 is ZnO, and its thickness is 15 nm. The conductive layer 121 is IWO (i.e., WO2 is doped into In2O3, and the content of In2O3 is 98 wt%), and the hole transport layer 40 is MoO3.

[0043] Regarding the PN junction 42, the thickness of the P-type nanosilicon layer 421 is 20 nm, and the thickness of the N-type nanosilicon layer 420 is 19 nm.

[0044] Regarding the light transport layer, the first light transport layer 41 and the second light transport layer 30 are the same. The first conductive layer 410 is ZnO, with a thickness of 60 nm and a refractive index of 2.0. The first protective layer 411 is Si, with a thickness of 1 nm and a refractive index of 3.8. The second conductive layer 412 is a mixture of AlTi and AlTiO x and its thickness is 15 nm and refractive index is 1.0. The second protective layer 413 is YZO, with a thickness of 25 nm and a refractive index of 2.0. The light emitting layer 414 is SiC, with a thickness of 75 nm and a refractive index of 1.55.

[0045] Regarding the heterojunction layer group 20, the thickness of the N-type Si wafer 201 is 0.2 mm. In the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204, the oxygen content is 20 wt% and the thickness is 7 nm. The thickness of the N-type amorphous silicon layer 203 is 10 nm, and the thickness of the P-type amorphous silicon layer 205 is 10 nm.

[0046] The first metal electrode layer 50 is Ag paste, and the second metal electrode layer 60 is Ag paste.

[0047] The efficiency of the laminated solar cell of Example 2 is shown in Table 1. 〈Example 3〉

[0048] Regarding the light absorption layer 10, the excitation layer 11 is a perovskite photosensitive layer FAPbI3. The electron transport layer 120 is SnO2, and its thickness is 15 nm. The conductive layer 121 is IWO (that is, WO2 is doped into In2O3, and the content of In2O3 is 90 wt%), and the hole transport layer 40 is WO3.

[0049] Regarding the PN junction 42, the thickness of the P-type nanosilicon layer 421 is 16 nm, and the thickness of the N-type nanosilicon layer 420 is 25 nm.

[0050] Regarding the light transport layer, the first light transport layer 41 and the second light transport layer 30 are the same. The first conductive layer 410 is FTO, with a thickness of 60 nm and a refractive index of 1.9. The first protective layer 411 is Cr, with a thickness of 1.5 nm and a refractive index of 2.7. The second conductive layer 412 is a mixture of AgZn and AgZnO x with a thickness of 9 nm and a refractive index of 0.3. The second protective layer 413 is TiO2, with a thickness of 15 nm and a refractive index of 2.0. The light emitting layer 414 is Ta2O5, with a thickness of 45 nm and a refractive index of 2.0.

[0051] Regarding the heterojunction layer group 20, the thickness of the N-type Si wafer 201 is 0.2 mm. In the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204, the oxygen content is 30 wt% and the thickness is 5 nm. The thickness of the N-type amorphous silicon layer 203 is 10 nm, and the thickness of the P-type amorphous silicon layer 205 is 10 nm.

[0052] The first metal electrode layer 50 is Ag paste, and the second metal electrode layer 60 is Ag paste.

[0053] The efficiency of the stacked solar cell of Example 3 is shown in Table 1. 〈Example 4〉

[0054] Regarding the light absorption layer 10, the excitation layer 11 is a perovskite photosensitive layer FAPbI3. The electron transport layer 120 is TiO2, and its thickness is 7 nm. The conductive layer 121 is AGZO (that is, ZnO is doped with Al2O3 and Ga2O3, the content of ZnO is 96 wt%, the content of Al2O3 is 2 wt%, and the remaining part is Ga2O3 and inevitable impurities), and the hole transport layer 40 is Cu2O.

[0055] Regarding the PN junction 42, the thickness of the P-type nanosilicon layer 421 is 28 nm, and the thickness of the N-type nanosilicon layer 420 is 10 nm.

[0056] Regarding the light transport layer, the first light transport layer 41 and the second light transport layer 30 are the same. The first conductive layer 410 is ITO, its thickness is 50 nm, and its refractive index is 1.9. The first protective layer 411 is SnO2, its thickness is 5 nm, and its refractive index is 2.0. The second conductive layer 412 is a mixture of CuNi and CuNiN x and its thickness is 20 nm, and its refractive index is 0.9. The second protective layer 413 is Si3N4, its thickness is 10 nm, and its refractive index is 2.0. The light emitting layer 414 is YZO, its thickness is 40 nm, and its refractive index is 2.0.

[0057] Regarding the heterojunction layer group 20, the thickness of the N-type Si wafer 201 is 0.2 mm. In the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204, the oxygen content is 15 wt%, and the thickness is 5 nm. The thickness of the N-type amorphous silicon layer 203 is 10 nm, and the thickness of the P-type amorphous silicon layer 205 is 10 nm.

[0058] The first metal electrode layer 50 is Ag paste, and the second metal electrode layer 60 is Ag paste.

[0059] The efficiency of the laminated solar cell of Example 4 is shown in Table 1. 〈Example 5〉

[0060] Regarding the light absorption layer 10, the excitation layer 11 is a perovskite photosensitive layer FAPbI3. The electron transport layer 120 is Al2O3 with a thickness of 5 nm. The conductive layer 121 is BGZO (that is, ZnO is doped with B2O3 and Ga2O3, the content of ZnO is 98 wt%, the content of B2O3 is 1 wt%, and the remaining part is Ga2O3 and inevitable impurities), and the hole transport layer 40 is CuO.

[0061] Regarding the PN junction 42, the thickness of the P-type nanosilicon layer 421 is 25 nm, and the thickness of the N-type nanosilicon layer 420 is 25 nm.

[0062] Regarding the light transport layer, the first light transport layer 41 and the second light transport layer 30 are the same. The first conductive layer 410 is ITiO with a thickness of 38 nm and a refractive index of 2.0. The first protective layer 411 is Al with a thickness of 2 nm and a refractive index of 0.9. The second conductive layer 412 is a mixture of AgAl and AgAlO x with a thickness of 7 nm and a refractive index of 0.3. The second protective layer 413 is TiN with a thickness of 7 nm and a refractive index of 2.0. The light emitting layer 414 is SnO2 with a thickness of 40 nm and a refractive index of 2.0.

[0063] Regarding the heterojunction layer group 20, the thickness of the N-type Si wafer 201 is 0.2 mm. In the first intrinsic amorphous silicon layer 202 and the second intrinsic amorphous silicon layer 204, the oxygen content is 20 wt% and the thickness is 6 nm. The thickness of the N-type amorphous silicon layer 203 is 10 nm, and the thickness of the P-type amorphous silicon layer 205 is 10 nm.

[0064] The first metal electrode layer 50 is Ag paste, and the second metal electrode layer 60 is Ag paste.

[0065] The efficiency of the stacked solar cell of Example 5 is shown in Table 1. 〈Comparative Example 1〉

[0066] The comparative example is a general perovskite solar cell in the prior art.

[0067] The excitation layer is the perovskite photosensitive layer FAPbI3. The electron transport layer is SnO2. The hole transport layer is CuO.

[0068] Table 1 shows the efficiencies of the stacked solar cells of the comparative examples.

[0069] JPEG0007703103000001.jpg43170

[0070] As shown in Table 1, the efficiencies of the stacked solar cells according to Examples 1 to 5 of the present application are relatively high, all being 30% or more. On the other hand, the efficiency of the solar cells in the prior art is about 20%. This shows that the efficiency of the stacked solar cells according to the present application is higher.

[0071] The above description is only for the examples of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. All corrections, equivalent substitutions, improvements, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A laminated solar cell comprising a light absorption layer group and a heterojunction layer group, wherein the light absorption layer group includes an excitation layer, a first electron transport layer group disposed on a first side surface of the excitation layer, and a first hole transport layer group disposed on a second side surface of the excitation layer, a first side surface of the heterojunction layer group is a second electron transport layer, which is in contact with the first hole transport layer group, and a second side surface of the heterojunction layer group is a second hole transport layer, upon irradiation with sunlight, both the excitation layer and the heterojunction layer group are excited, electrons generated in the excitation layer are transported out of the laminated solar cell through the first electron transport layer group, holes generated in the excitation layer flow through the first hole transport layer group to the heterojunction layer group, recombine with electrons generated in the heterojunction layer group, and holes generated in the heterojunction layer group are transported out of the laminated solar cell from the second hole transport layer, the first hole transport layer group includes a hole transport layer in contact with the excitation layer, a PN junction in contact with the hole transport layer, and a first light transport layer in contact with the PN junction, the first light transport layer is in contact with the second electron transport layer, the first light transport layer includes a first conductive layer in contact with the PN junction, a first protective layer in contact with the first conductive layer, a second conductive layer in contact with the first protective layer, a second protective layer in contact with the second conductive layer, and a light emitting layer in contact with the second protective layer, the first conductive layer has a first refractive index n1 and a first thickness d1, the first protective layer has a second refractive index n2 and a second thickness d2, the second conductive layer has a third refractive index n3 and a third thickness d3, the second protective layer has a fourth refractive index n4 and a fourth thickness d4, and the light emitting layer has a fifth refractive index n5 and a fifth thickness d5, where n1 is between 1.8 and 2.1, d1 is between 20 nm and 80 nm, n2 is between 0.1 and 5, d2 is between 0.5 nm and 10 nm, n3 is between 0.1 and 1.5, d3 is between 5 nm and 50 nm, n4 is between 1.3 and 2.1, d4 is between 0.5 nm and 25 nm, n5 is between 1.4 and 2.4, and d5 is between 20 nm and 80 nm, A laminated solar cell characterized by the above.

2. The first conductive layer includes a conductive metal oxide, the first protective layer includes one of a metal, a conductive metal oxide, and a conductive metal nitride, the second conductive layer includes a conductive material and a metal oxide and / or a metal nitride, the second protective layer includes one of a non-metal oxide, a metal nitride, and a metal oxide. The laminated solar cell according to claim 1, wherein the light-emitting layer contains one of non-metallic oxides, nitrides, sulfides, fluorides, and carbides.

3. The material of the first conductive layer is In ２ O ３ , SnO ２ , ZnO, ITO, AZO, IZO, ITiO, IZTO, or FTO, and is one selected therefrom. The material of the first protective layer is one selected from Si, Ti, Al, Ni, Cr, NiCr, TiN, ZnO, TiO ２ , SnO ２ , SiO ２ , Nb ２ O ５ , Ta ２ O ５ and Si ３ N ４ and is one selected therefrom, The conductive material of the second conductive layer is one selected from Ag, Cu, Al, Mo, Ag alloy, Cu alloy, Al alloy, and Mo alloy, and further includes inclusions formed of oxides and / or nitrides of the conductive material of the second conductive layer. The material of the second protective layer is one selected from TiN, ZnO, TiO ２ , SnO ２ , SiO ２ , Si ３ N ４ , AZO, IZO, and YZO, The material of the light-emitting layer is TiO ２ , SnO ２ , ZnO, Nb ２ O ５ , Ta ２ O ５ , Si ３ N ４ , ZnS, SiO ２ , Al ２ O ３ , MgF, MgS, SiC, AZO, GZO, or YZO, and the laminated solar cell according to claim 2, characterized in that it is one selected from the group consisting of

4. The heterojunction layer group an N-type Si wafer, a first intrinsic amorphous silicon layer located on the first surface of the N-type Si wafer and doped with oxygen, an N-type amorphous silicon layer located on the first intrinsic amorphous silicon layer and forming the second electron transport layer, a second intrinsic amorphous silicon layer located on the second surface of the N-type Si wafer and the same as the first intrinsic amorphous silicon layer, a P-type amorphous silicon layer located on the second intrinsic amorphous silicon layer and forming the second hole transport layer, and includes the laminated solar cell according to any one of claims 1 to 3.

5. In the first intrinsic amorphous silicon layer, the oxygen content is greater than 0 and 30 wt% or less, and the laminated solar cell according to claim 4 is characterized in that.

6. A second light transport layer is further provided outside the P-type amorphous silicon layer. The second light transport layer is the same as the first light transport layer. The refractive index of the P-type amorphous silicon layer is between 3.2 and 3.8, and the thickness is between 0 and 60 nm. The laminated solar cell according to claim 5 is characterized in that.

7. The PN junction includes an N-type nanosilicon layer in contact with the first light transport layer and a P-type nanosilicon layer located on the N-type nanosilicon layer. The P-type nanosilicon layer is in contact with the hole transport layer. The laminated solar cell according to any one of claims 1 to 4 is characterized in that.

8. The first electron transport layer group includes an electron transport layer in contact with the excitation layer and a conductive layer in contact with the electron transport layer. The laminated solar cell according to claim 1 is characterized in that.

9. The material of the conductive layer is In ２ O ３ and the dopant is Ga ２ O ３ , ZnO ２ , CeO ２ , TiO ２ , Mo ２ O ３ , ZrO ２ and WO ２ or one or more of them, and the weight content of In ２ O ３ is between 80 wt% and 100 wt%, and the remaining part is the dopant and inevitable impurities, or The material of the conductive layer is ZnO, and the dopant is SnO ２ , Al ２ O ３ , Ga ２ O ３ , B ２ O ３ One or more of them, and the weight content of ZnO is between 80 wt% and 100 wt%, and the remaining part is a dopant and inevitable impurities. The laminated solar cell according to claim 8, characterized in that.

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