A flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection

Abstract

The invention discloses a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, which belongs to the technical field of solar cells and includes a top-incident structure and a bottom-incident structure; the top-incident structure sequentially arranges an ultraviolet DBR reflection layer, an ultraviolet light absorption layer, an ultrathin metal electrode, an anode buffer layer, an active layer doped with nanoparticles, a cathode buffer layer, a thick metal electrode, a near-infrared DBR reflection layer and a flexible substrate from top to bottom; the bottom-incident structure sequentially arranges a flexible substrate, an ultraviolet DBR reflection layer, an ultrathin metal electrode, an ultraviolet light absorption layer, an active layer doped with nanoparticles, an anode buffer layer, a thick metal electrode and a near-infrared DBR reflection layer from bottom to top. The invention reflects long-wave near-infrared light and short-wave ultraviolet light, enhances the local coupling intensity of light fields in other wavebands, broadens the light field coupling range, balances the photoelectric conversion efficiency and the visible light transmittance, and realizes a solar cell with high efficiency, long life and self-cooling.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells, and in particular relates to a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection. Background Art

[0002] As a renewable green energy to solve the energy crisis and environmental pollution, solar energy has attracted much attention from all countries. Among various ways of utilizing solar energy, organic solar cells have been widely studied by energy ministries and scientists in various countries due to their outstanding advantages such as easy material synthesis, wide sources of raw materials, simple manufacturing process, low cost, low energy consumption, low environmental pollution, and easy large-scale production. Among them, flexible semi-transparent organic solar cells have the advantages of transparency and color adjustability. They can not only be used in the integration of buildings and mobile terminals and the manufacture of wearable electronic devices, but also form differentiated development with silicon-based solar cells in different application fields. Therefore, the development of flexible semi-transparent organic solar cell technology has significant social and economic benefits and strategic significance. When semi-transparent organic solar cells are used in scenes such as semi-transparent windows, building decorations, and automotive glass, they will face more practical needs. For example, when the summer sunlight is too bright and the indoor temperature is too high, the semi-transparent windows need to have the function of reflecting heat. At the same time, the ultraviolet rays in the sunlight are very harmful to the human body and will cause the aging of organic thin film materials, which will seriously affect the service life of the device. Therefore, the study of solar cells with self-cooling and reduced ultraviolet transmittance has become a current research hotspot. Although the cell efficiency of organic solar cells based on rigid substrates has exceeded 18% in recent years, the photoelectric conversion efficiency of organic semi-transparent solar cells is still low (~12%) when maintaining a transmittance of 24%, and the efficiency and stability of the device are far from meeting the requirements of commercial applications. In order to improve commercial feasibility, solar cells are required not only to have high conversion efficiency, but also to maintain light, thermal and mechanical stability during their cycle. Therefore, in order to improve the competitiveness of flexible organic solar cells in the photovoltaic field, key breakthroughs in photoelectric conversion efficiency, device stability, etc. are urgently needed. In addition, how to construct a multifunctional organic solar cell device that can reduce ultraviolet incident light and has near-infrared cooling through a simple design is another major problem in this field. Summary of the invention

[0003] The purpose of the present invention is to address the problems in the above-mentioned prior art and provide a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, which increases the light field coupling intensity of visible light while reflecting long-wave near-infrared and ultraviolet light, and provides a new idea for solving the balance and restriction problems between photoelectric conversion efficiency and visible light transmittance.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, characterized in that it includes a top-incident structure and a bottom-incident structure;

[0006] The top-incident structure includes an ultraviolet DBR (distributed Bragg reflector) reflection layer, an ultraviolet light absorption layer, an ultrathin metal electrode, an anode buffer layer, a nanoparticle-doped active layer, a cathode buffer layer, a thick metal electrode, a near-infrared DBR reflection layer and a flexible substrate, which are arranged in sequence from top to bottom; the flexible substrate, the near-infrared DBR reflection layer, the thick metal electrode, the cathode buffer layer, the nanoparticle-doped active layer, the anode buffer layer, the ultrathin metal electrode and the ultraviolet light absorption layer all have surface microstructures;

[0007] The bottom-incident structure comprises a flexible substrate, an ultraviolet DBR reflective layer, an ultrathin metal electrode, an ultraviolet light absorbing layer, a nanoparticle-doped active layer, an anode buffer layer, a thick metal electrode and a near-infrared DBR reflective layer, which are arranged in sequence from bottom to top; the flexible substrate, the ultraviolet DBR reflective layer, the ultrathin metal electrode, the ultraviolet light absorbing layer, the nanoparticle-doped active layer, the anode buffer layer and the thick metal electrode all have surface microstructures;

[0008] A metal microcavity structure is formed between the thick metal electrode and the ultra-thin metal electrode of the top-incident structure and the bottom-incident structure, and metal nanowires are arranged on the upper surface of the ultra-thin metal electrode.

[0009] Furthermore, the ultraviolet light absorbing layer in the bottom-incident structure has a cathode buffer function.

[0010] Furthermore, the thickness of the active layer doped with nanoparticles is 100-250 nm, and the doping concentration of the nanoparticles is 0.5 wt%-2 wt%.

[0011] Furthermore, in the nanoparticle-doped active layer, the active layer material is a bulk heterojunction (BHJ) structure mixed film or a perovskite film;

[0012] The donor materials of the bulk heterojunction structure mixed film include P3HT (polytrihexylthiophene), PM6 (poly[[4,8-bis[5-(2-ethylhexyl)-4-fluoro-2-thieno]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxy-4H,8H-benzo[1,2-c:4,5-c′]dithiophene-1,3-diyl]-2,5-thiophenediyl]), PBDB-T (poly[[4,8-bis[5-(2-ethylhexyl)-4-fluoro-2-thieno]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl]-2,5-thiophenediyl]), 3-fluoro-2-((2-ethylhexyl)-2-thiophene)benzo[1,2-b:4,5-b]dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c]dithiophene-1,3-diyl]]), PTB7-Th (poly[2,6′]-4,8-bis(5-ethylhexylthiophene)benzo[1,2-b;3,3-b]dithiophene]{3-fluoro-2[(2-ethylhexyl)carbonyl]thiophene[3,4-b]thiophenediyl})), D18 (poly[2,6′]-4,8-bis(5-ethylhexylthiophene)benzo[1,2-b;3,3-b]dithiophene]{3-fluoro-2[(2-ethylhexyl)carbonyl]thiophene[3,4-b]thiophenediyl})), [(2,6-4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophene-2-benzo[1,2-b:4,5-b]dithiophene))-alt-(2-butyl)thiophen-2-yl)-8-(4-(2-butyl)-5-methylthiophen-2-yl)dithiophene[3,2,3,4;2,3,5,6]benzo[1,2-c][1,2,5]thiadiazole)]), PBDTTT-CT (poly[[4,8-bis[5-(2-ethylhexyl)-2-thiophene]benzo[1,2-b:4,5-b']diphenyl Phenol-2,6-diphenyl][2-(2-(2-ethyl 1-oxymethyl)thiomethyl[3,4-b]thiophenyl]]]), PffBT4T-2DT (poly[(5,6-difluoro-2,1,3-benzothiadiazole)-alt-(3,3"'-bis(2-octyldodecyl)-2,2'; 5",2"'-quadithiophene)), etc., and the receptor material includes ICBA (1',1',4',4'-tetrahydro-di[1,4]methanenaphthalene [1,2:2',3',56,60:2',3'][5,6]fullerene-C 60 ), PC 71 BM([6,6]-phenyl C 71 Methyl butyrate), PC 61 BM([6,6]-phenyl C 61butyric acid methyl ester) and other fullerene materials, and ITIC (2,2'-[[[6,6,12,12-tetrakis(4-hexylphenyl)-6,12-dihydrodithio[2,3-d:2',3'-d']-s-indolol[1,2-b:5,6-b']dithiophene-2,8-diyl]bis[methylene(3-oxo-1H-indene-2,1(3H)-dimethylene)]]bis[propylamine ]), IT-4F (3,9-bis(2-methylene((3-(1,1-dicyanomethyl)-6,7-difluoro)-indanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithiophene[2,3-d:2',3'-d']-s-indeno[1,2-b:5,6-b']dithiophene), Y6 (12,13-bis(2-ethylhexyl)-3,9-diundecyl-1 2,13-Dihydro-[1,2,5]thiadiazo[3,4-e]thieno[2”,3”:4’,5’]thieno[2’,3’:4,5]pyrrolo[3,2-g]thieno[2’,3’:4,5]thieno[3,2-b]indole-2,10-bis(5,6-difluoro-3-(dicyanomethylene)indene-1-one)), IEICO-4F(2,2-((2 Non-fullerene materials such as (Z,2Z)-((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-octadiene[1,2-b:5,6-b]dithiophene-2,7-diyl)bis(4-(2-ethylhexyl)oxy)thiophene-5,2-diyl)bis(methylmethylene))bis(5,6-difluoro-3-oxy-2,3-dihydro-1h-indene-2,1-diylidene))dimalononitrile);

[0013] The material of the perovskite film includes ABM 3 Halogen perovskite materials, ABM 1 x M 2 3-x (0<X<3) Halogen substituted solid solution perovskite materials, A 1 x A 2 1-x BM(0<X<1) monovalent cation substituted perovskite materials, AB 1 x B 2 1-x M(0<X<1) metal-substituted solid solution perovskite materials, two-dimensional perovskite materials, and ABM 3 Halogen perovskite materials, ABM 1 x M 2 3-x (0<X<3) Halogen substituted solid solution perovskite materials, A 1 x A2 1-x BM(0<X<1) monovalent cation substituted perovskite materials, AB 1 x B 2 1-x M(0<X<1) is a mixture of metal-substituted solid solution perovskite materials and two-dimensional perovskite materials; wherein A, A 1 , A 2 For monovalent non-coordinating cations, including Cs (cesium), CH 3 NH 3 (methylamine) or HC(NH 2 ) 2 (methyl amine); B, B 1 , B 2 is a divalent P-block metal, including Pb (lead), Sn (tin) or Ge (germanium); M, M 1 、M 2 It is a halogen anion coordinated to the metal, including F (fluorine), Cl (chlorine), Br (bromine) or I (iodine).

[0014] Furthermore, in the nanoparticle-doped active layer, the nanoparticles include graphene quantum dots (GODs), carbon nanotubes (CNTs), gold (Au) nanoparticles, silver (Ag) nanoparticles, silicon (Si) nanoparticles or nickel (Ni) nanoparticles, etc., with a size of 10 to 70 nm; the shapes of the nanoparticles include nanospheres, nanodisks or nanotubes.

[0015] Furthermore, the flexible substrate includes high molecular polymer PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PI (polyimide), PE (polyethylene), Parylene (polyparaxylene), PES (polyether sulfone) or PDMS (polydimethylsiloxane), and has a thickness of 2 to 50 μm.

[0016] Furthermore, the near-infrared DBR reflective layer comprises (LiF (lithium fluoride) / MoO 3 (Molybdenum trioxide) n 、(CA(cellulose acetate) / PVK(poly(N-vinyl carbazole))) m or (PAA(polyacrylamide) / PVK) l ; Where n, m and l are the number of film layers, n is 1 or 2, m is 40 to 43, and l is 40 to 43; single layer LiF and MoO 3 The thicknesses of single-layer CA and PVK are 100-120nm and 60-120nm respectively; the thicknesses of single-layer PAA and PVK are 220-330nm and 200-295nm respectively; the thicknesses of single-layer PAA and PVK are 160-240nm and 140-210nm respectively.

[0017] Furthermore, the thick metal electrode, ultra-thin metal electrode and metal nanowire are all made of Ag, and have thicknesses of 100 nm, 6 nm and 10-15 nm respectively.

[0018] Furthermore, the cathode buffer layer includes ZnO (zinc oxide), TiO 2 (TiO2), SnO 2 (tin dioxide), PEIE (polyethoxyethyleneimine), PC 61 BM, PC 71 BM, etc., with a thickness of 30 to 50 nm.

[0019] Furthermore, the anode buffer layer comprises MoO 3 , CuSCN (copper thiocyanate), V 2 O 5 (vanadium pentoxide), NiO x (nickel oxide), WO 3 (tungsten trioxide), PANI (polyaniline), PEDOT:PSS (poly(ethylenedioxythiophene):polystyrene sulfonate), TAPC (4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline]), Spiro-OMeTAD (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene), PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), etc., with a thickness of 5nm.

[0020] Furthermore, the ultraviolet light absorbing layer includes ZnO x 、TiO x or TeO 2 (tellurium dioxide), the thickness of the ultraviolet light absorbing layer in the top-incident structure is 1 μm, and the thickness of the ultraviolet light absorbing layer in the bottom-incident structure is 50 nm.

[0021] Furthermore, the ultraviolet DBR reflective layer (Ta 2 O 5 (Thallium pentoxide) / SiO 2 (Silicon Dioxide) p 、(SiO 2 / YDH(doped Y 2 O 3 (Yttrium oxide) HfO 2 (Hafnium dioxide))) q or (TiO 2 / SiO x ) k ; Where p, q and k are the number of film layers, p is 31, q is 10-15, k is 6 or 7; single layer Ta 2O 5 and SiO 2 The thicknesses of the single-layer SiO 2 The thicknesses of TiO and YDH are 30nm and 29nm respectively; 2 and SiO x The thicknesses are 30nm and 70nm respectively.

[0022] Furthermore, the surface microstructure is cylindrical or polygonal in shape, with a size of 200 to 500 nm and a height of 5 to 20 nm.

[0023] Furthermore, the shape and size of the surface microstructure, the shape and size of the nanoparticles, and the thickness of the near-infrared DBR reflective layer and the ultraviolet DBR reflective layer are determined by optical transmission matrix and finite element analysis theoretical simulation.

[0024] The present invention also proposes a method for preparing the flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, characterized in that the flexible microcavity solar cell is a top-incident structure, and the preparation method comprises the following steps:

[0025] SA1: Based on the optical transmission matrix and finite element analysis theory, an optical simulation model of surface microstructure and nanoparticle doping is constructed. Light field simulation is performed for different incident light wavelengths to obtain the influence of the shape and size of the surface microstructure, as well as the shape and size of the nanoparticles on the wavelength range and local enhancement rate of the plasma effect, and then the preferred surface microstructure and preferred nanoparticles corresponding to the wavelength of the incident light are selected; at the same time, according to the materials of the near-infrared DBR reflective layer and the ultraviolet DBR reflective layer used, the specific thickness and number of layers are determined through optical transmission matrix theoretical simulation;

[0026] SA2: A silicon template with a preferred surface microstructure etched on it is used to emboss the preferred surface microstructure on a flexible substrate;

[0027] SA3: A near-infrared DBR reflective layer and a thick metal electrode are sequentially prepared on a flexible substrate, and the thick metal electrode is imprinted with a silicon template etched with a preferred surface microstructure to enhance the preferred surface microstructure;

[0028] SA4: a cathode buffer layer and an active layer doped with preferred nanoparticles are sequentially prepared on a thick metal electrode, and the active layer doped with preferred nanoparticles is imprinted with a silicon template etched with a preferred surface microstructure to enhance the preferred surface microstructure;

[0029] SA5: An anode buffer layer, an ultrathin metal electrode, a metal nanowire and a UV absorption layer are sequentially prepared on the nanoparticle-doped active layer, and then a UV DBR reflection layer is prepared on a flexible substrate. The UV DBR reflection layer is then transferred to the upper surface of the UV absorption layer, and finally a flexible microcavity solar cell with long-wave near-infrared and UV reflection is obtained.

[0030] The flexible microcavity solar cell is a bottom-incident structure, and the preparation method comprises the following steps:

[0031] SB1: Based on the optical transmission matrix and finite element analysis theory, an optical simulation model of surface microstructure and nanoparticle doping is constructed. Light field simulation is performed for different incident light wavelengths to obtain the influence of the shape and size of the surface microstructure, as well as the shape and size of the nanoparticles on the wavelength range of the plasma effect and the local enhancement rate, and then the preferred surface microstructure and preferred nanoparticles corresponding to the wavelength of the incident light are selected; at the same time, according to the materials of the near-infrared DBR reflective layer and the ultraviolet DBR reflective layer used, the specific thickness and number of layers are determined through optical transmission matrix theoretical simulation;

[0032] SB2: Using a silicon template etched with a preferred surface microstructure, the preferred surface microstructure is imprinted on a flexible substrate;

[0033] SB3: A UV DBR reflective layer, an ultrathin metal electrode and metal nanowires are sequentially prepared on a flexible substrate and imprinted with a silicon template etched with a preferred surface microstructure to enhance the preferred surface microstructure;

[0034] SB4: sequentially preparing an ultraviolet light absorbing layer and an active layer doped with preferred nanoparticles on the metal nanowires, and imprinting the active layer doped with preferred nanoparticles with a silicon template etched with a preferred surface microstructure to enhance the preferred surface microstructure;

[0035] SB5: An anode buffer layer and a thick metal electrode are sequentially prepared on the nanoparticle-doped active layer, and then a near-infrared DBR reflective layer is prepared on a flexible substrate. The near-infrared DBR reflective layer is then transferred to the upper surface of the thick metal electrode, and finally a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection is obtained.

[0036] The working principle of the flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection described in the present invention is:

[0037] When the flexible microcavity solar cell is a top-incident structure, the incident light is incident on the flexible microcavity solar cell from the top, and first passes through the UV DBR reflective layer, most of the UV light is reflected out, avoiding damage to the device caused by high-energy UV light; then the UV absorption layer further absorbs the short-wavelength UV part of the incident light, thereby ensuring that the device has a longer life; the incident light passes through the metal nanowires and ultra-thin metal electrodes, and reflects back and forth in the metal microcavity structure, improving the light absorption efficiency. At the same time, the incident light passes through the nanoparticles doped in the metal microcavity structure. When the active layer is formed, the plasmon coupling effect and light scattering effect of the nanoparticles further improve the light utilization efficiency, thereby enhancing the photocurrent and improving the photoelectric conversion efficiency; then the incident light passes through the near-infrared DBR reflective layer, and partially reflects the long-wave near-infrared light (1100-2526nm) with thermal effect, making it unable to pass through the device, thereby blocking the long-wave near-infrared light from continuously heating the device itself and the object illuminated by the transmitted light, which not only enables the device to have an automatic temperature control function, but also avoids the impact of long-term heating on the device life.

[0038] When the flexible microcavity solar cell is a bottom-incident structure, the incident light is incident on the flexible microcavity solar cell from the bottom, and the working process and effect of the incident light in the flexible microcavity solar cell are similar to those of the top-incident type; in addition, the ultraviolet light absorption layer therein also has the function of cathode buffering, and the thickness is set to 50nm, which helps to improve the efficiency of the device.

[0039] The beneficial effects of the present invention are:

[0040] 1. The present invention proposes a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection. While reflecting long-wave near-infrared light and short-wave ultraviolet light, it enhances the local coupling intensity of light fields in other bands, effectively broadens the light field coupling range of metal microcavity optical structures, and provides a new idea for solving the balance and restriction problem between photoelectric conversion efficiency and visible light transmittance. In addition, while improving efficiency, it can well deal with the stability problem of aging of the molecular structure of organic photosensitive materials caused by high-energy ultraviolet light, thus realizing a high-efficiency, long-life, self-cooling semi-transparent solar cell.

[0041] 2. The present invention sets one side of the planar composite electrode as an ultra-thin metal electrode to increase the transmittance of incident light, and sets a metal nanowire as an auxiliary electrode on the upper surface of the ultra-thin metal electrode to enhance the conductivity of the ultra-thin metal electrode, thereby improving the transmittance of visible light-short wavelength near-infrared light while ensuring the optical coupling characteristics of the metal microcavity;

[0042] 3. The present invention enhances the light coupling intensity of a specific wavelength by setting a surface microstructure of a specific structure and size, and then adds nanoparticles into the active layer to improve the light utilization efficiency, thereby improving the photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic structural diagram of a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection provided in Example 1 of the present invention;

[0044] Figure 2 A schematic diagram of the working principle of a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection provided in Example 1 of the present invention;

[0045] Figure 3 A schematic diagram of the structure of a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection provided in Example 4 of the present invention;

[0046] Figure 4 A schematic diagram of the working principle of a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection provided in Example 4 of the present invention;

[0047] The descriptions of the symbols in the accompanying drawings are as follows:

[0048] 1: flexible substrate; 2: near-infrared DBR reflective layer; 3: thick metal electrode; 4: cathode buffer layer; 5: nanoparticle-doped active layer; 6: anode buffer layer; 7: ultrathin metal electrode; 8: ultraviolet light absorption layer; 9: ultraviolet light DBR reflective layer; 10: incident light; 11: silicon template. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] Example 1

[0051] This embodiment provides a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, which is a top-incident structure, such as Figure 1 As shown, it includes an ultraviolet DBR reflective layer 9, an ultraviolet light absorbing layer 8, an ultrathin metal electrode 7, an anode buffer layer 6, a nanoparticle-doped active layer 5, a cathode buffer layer 4, a thick metal electrode 3, a near-infrared DBR reflective layer 2 and a flexible substrate 1 which are arranged in sequence from top to bottom;

[0052] The flexible substrate 1, the near-infrared DBR reflective layer 2, the thick metal electrode 3, the cathode buffer layer 4, the nanoparticle-doped active layer 5, the anode buffer layer 6, the ultrathin metal electrode 7, and the ultraviolet light absorbing layer 8 all have surface microstructures;

[0053] A metal microcavity structure is formed between the thick metal electrode 3 and the ultra-thin metal electrode 7 , and Ag metal nanowires are arranged on the upper surface of the ultra-thin metal electrode 7 .

[0054] Wherein, the flexible substrate 1 adopts a PDMS substrate with a thickness of 20 μm;

[0055] The near-infrared DBR reflective layer 2 is composed of two layers (100nm LiF / 60nm MoO 3 )structure;

[0056] The thick metal electrode 3 is an Ag electrode with a thickness of 100 nm;

[0057] The cathode buffer layer 4 is a ZnO film with a thickness of 30 nm;

[0058] The nanoparticle-doped active layer 5 is a PM6:Y6 film with a thickness of 120 nm, and the nanoparticles used are Au nanospheres with a size of 30 nm; the doping concentration of the nanoparticles is 0.5 wt%;

[0059] The anode buffer layer 6 is made of MoO with a thickness of 5 nm. 3 film;

[0060] The ultra-thin metal electrode 7 is a 6 nm thick Ag electrode;

[0061] The thickness of the Ag metal nanowire is 15 nm;

[0062] The ultraviolet light absorbing layer 8 is a ZnO thin film with a thickness of 1 μm;

[0063] The ultraviolet DBR reflective layer 9 is made of 31 layers with a total thickness of 15 μm and a thickness ratio of 0.6:1 (Ta 2 O 5 / SiO 2 )structure;

[0064] The surface microstructure is obtained by imprinting a silicon template 11 with a cylindrical array structure having a diameter of 300 nm and a height of 20 nm.

[0065] This embodiment also proposes a method for preparing the above-mentioned flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, comprising the following steps:

[0066] S1: Based on the optical transmission matrix and finite element analysis theory, an optical simulation model of surface microstructure and nanoparticle doping is constructed. Light field simulation is performed for different incident light wavelengths to obtain the influence of the shape and size of the surface microstructure, as well as the shape and size of the nanoparticles on the wavelength range of the plasma effect and the local enhancement rate, and then the preferred surface microstructure and preferred nanoparticles corresponding to the incident light wavelength are selected;

[0067] S2: using a silicon template 11 etched with a preferred surface microstructure to emboss the preferred surface microstructure on the flexible substrate 1;

[0068] S3: The vacuum evaporation method is used on the flexible substrate 1 with a vacuum degree of less than 3.0×10 -3 100nm LiF and 30nm MoO were sequentially deposited under Pa environment. 3 , repeat this operation twice to prepare a near-infrared DBR reflective layer 2;

[0069] S4: The near-infrared DBR reflective layer 2 is deposited by vacuum evaporation at a vacuum degree of less than 3.0×10 -3 100 nm of metal electrode Ag is evaporated in an environment of Pa to prepare a thick metal electrode 3, and the thick metal electrode 3 is imprinted with a silicon template 11 etched with a preferred surface microstructure to enhance the preferred surface microstructure;

[0070] S5: spin coating ZnO on the thick metal electrode 3 at 5000 rpm for 40 seconds, and then performing annealing treatment, with the annealing temperature controlled at 150° C. for 15 minutes, to prepare a cathode buffer layer 4;

[0071] S6: preparing an active layer solution doped with Au nanoparticles: PM6 and Y6 were mixed in a mass ratio of 1:1.2, 0.5 wt% Au nanoparticles were added, chloroform solvent and 0.5% by volume of chloronaphthalene additive were added to prepare a 16 mg / ml solution, and the solution was stirred and dissolved at 30°C and 600 rpm for 12 h;

[0072] S7: Spin-coating the active layer solution doped with Au nanoparticles on the cathode buffer layer 4, controlling the rotation speed to 2500 rpm, the spin-coating time to 30 seconds, and then annealing at 110° C. for 10 minutes to obtain the active layer 5 doped with nanoparticles; and imprinting the active layer 5 doped with nanoparticles with a silicon template 11 etched with a preferred surface microstructure to enhance the preferred surface microstructure;

[0073] S8: vacuum evaporation is used on the nanoparticle-doped active layer 5 at a vacuum degree of less than 3.0×10 -3 5 nm MoO was deposited in a Pa environment 3 , an anode buffer layer 6 is prepared;

[0074] S9: placing the anode buffer layer 6 into a metal evaporation chamber, evaporating a 6 nm Ag ultra-thin metal electrode 7, and then spin-coating a layer of Ag nanowires with a thickness of 15 nm on the Ag ultra-thin metal electrode 7;

[0075] S10: Spin-coating 1 μm ZnO on the Ag nanowire as the ultraviolet light absorption layer 8 by spin coating;

[0076] S11: Using the evaporation method, 181nm Ta is sequentially evaporated on the flexible substrate 2 O 5 and 302nm SiO 2 The film is made by repeating the operation 31 times to obtain the ultraviolet DBR reflective layer 9, and then the ultraviolet DBR reflective layer 9 is transferred to the upper surface of the ultraviolet light absorption layer 8, and finally a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection is obtained.

[0077] like Figure 2 As shown, the working principle of the flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection described in this embodiment is as follows: the incident light 10 is incident on the flexible microcavity solar cell, and first passes through the ultraviolet light DBR reflection layer 9, most of the ultraviolet light is reflected out, avoiding the damage of high-energy ultraviolet light to the device; then the ultraviolet light absorption layer 8 further absorbs the ultraviolet short-wavelength part of the incident light, thereby ensuring that the device has a longer life; the incident light 10 passes through the metal nanowires and the ultrathin metal electrode 7, and reflects back and forth in the metal microcavity structure, thereby improving the light absorption efficiency, and at the same time, the incident light 10 passes through the metal nanowires and the ultrathin metal electrode 7, and then reflects back and forth in the metal microcavity structure, thereby improving the light absorption efficiency, and at the same time, the incident light 10 passes through the metal When the active layer 5 is doped with nanoparticles in the microcavity structure, the light utilization efficiency is further improved due to the plasmon coupling effect and light scattering effect of the nanoparticles, thereby enhancing the photocurrent and improving the photoelectric conversion efficiency; then the incident light passes through the near-infrared DBR reflective layer 2, and partially reflects the long-wave near-infrared light (1100-2526nm) with thermal effect, making it unable to pass through the device, thereby blocking the long-wave near-infrared light from continuously heating the device itself and the object irradiated by the transmitted light, which not only enables the device to have an automatic temperature control function, but also avoids the impact of long-term heating on the device life.

[0078] Under standard testing, a beam of light is drawn from the light source so that the incident light 10 is irradiated on the device. In the range of 400-1100nm, the external quantum efficiency (EQE) reaches more than 70%, and the short-circuit current is 25.31mA / cm 2 , open circuit voltage is 0.83V, fill factor is 0.77, efficiency reaches 13.5%, average visible light transmittance reaches 23.2%, UV reflectivity and absorption rate are >90%, T 80 Lifespan>4000 hours, near-infrared light reflectivity>95% at wavelength>1300nm, near-infrared light heating is slowed down by more than 79%.

[0079] Example 2

[0080] This embodiment provides a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection. The structure is different from that of Embodiment 1 in that the material of the near-infrared DBR reflection layer 2 is replaced with (CA / PVK), and 300 nm of CA and 220 nm of PVK are sequentially spin-coated on the flexible substrate 1 by spin coating, and the operation is repeated 43 times. The other structures remain unchanged.

[0081] Under standard test, a beam is drawn from the light source so that the incident light 10 is irradiated on the device. In the range of 400-1100nm, the EQE reaches more than 72%, and the short-circuit current is 24.38mA / cm 2 , the open circuit voltage is 0.80V, the fill factor is 0.72, the efficiency reaches 12.3%, the average visible light transmittance reaches 24.3%, the UV reflectivity and absorption rate are >90% in total, the T80 life under UV light irradiation is >4000 hours, the near-infrared light reflectivity with a wavelength >1300nm is >93%, and the near-infrared light heating is slowed down by more than 75%.

[0082] Example 3

[0083] This embodiment provides a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection. The structure is different from that of embodiment 1 only in that the material of the ultraviolet DBR reflection layer 9 is replaced with (TiO 2 / SiO x ), 30 nm of TiO is sequentially sputtered on the flexible substrate 1 by magnetron sputtering. 2 and 70nm SiO x , repeat this operation 6 times. The other structures remain unchanged.

[0084] Under standard test, a beam is drawn from the light source so that the incident light 10 is irradiated on the device. In the range of 400-1100nm, the EQE reaches more than 80%, and the short-circuit current is 25.88mA / cm 2 , the open circuit voltage is 0.82V, the fill factor is 0.76, the efficiency reaches 13.8%, the average visible light transmittance reaches 25.1%, the UV reflectivity and absorption rate are >92% in total, the T80 life under UV light is >4000 hours, the near-infrared light reflectivity with a wavelength >1300nm is >95%, and the near-infrared light heating is slowed down by more than 80%.

[0085] Example 4

[0086] This embodiment provides a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, which is a bottom-incident structure, such as Figure 3As shown, it includes a flexible substrate 1, an ultraviolet DBR reflective layer 9, an ultrathin metal electrode 7, an ultraviolet light absorbing layer 8, a nanoparticle-doped active layer 5, an anode buffer layer 6, a thick and thin metal electrode 3, and a near-infrared DBR reflective layer 2, which are arranged in sequence from bottom to top;

[0087] The flexible substrate 1, the ultraviolet DBR reflective layer 9, the ultrathin metal electrode 7, the ultraviolet light absorbing layer 8, the nanoparticle-doped active layer 5, and the anode buffer layer 6 all have surface microstructures;

[0088] A metal microcavity structure is formed between the thick metal electrode 3 and the ultra-thin metal electrode 7 , and Ag metal nanowires are arranged on the upper surface of the ultra-thin metal electrode 7 .

[0089] The materials and specifications of the various parts included in the above bottom-incident structure are basically the same as those of the top-incident structure in Example 1, with the only difference being that the ultraviolet light absorption layer 8 is a ZnO thin film with a thickness of 50 nm and also has the function of cathode buffering.

[0090] This embodiment also proposes a method for preparing the above-mentioned flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, comprising the following steps:

[0091] S1: Based on the optical transmission matrix and finite element analysis theory, an optical simulation model of surface microstructure and nanoparticle doping is constructed. Light field simulation is performed for different incident light wavelengths to obtain the influence of the shape and size of the surface microstructure, as well as the shape and size of the nanoparticles on the wavelength range of the plasma effect and the local enhancement rate, and then the preferred surface microstructure and preferred nanoparticles corresponding to the incident light wavelength are selected;

[0092] S2: using a silicon template 11 etched with a preferred surface microstructure to emboss the preferred surface microstructure on the flexible substrate 1;

[0093] S3: The vacuum evaporation method is used on the flexible substrate 1 with a vacuum degree of less than 3.0×10 -3 Using the evaporation method in the Pa environment, 181nm Ta was deposited in sequence 2 O 5 and 302nm SiO 2 The film is made of a UV-C DBR reflective layer 9, and the operation is repeated 31 times.

[0094] S4: placing the UV DBR reflective layer 9 into a metal evaporation chamber, evaporating a 6 nm Ag ultra-thin metal electrode 7, then spin-coating a layer of Ag nanowires with a thickness of 15 nm on the Ag ultra-thin metal electrode 7, and using a silicon template 11 etched with a preferred surface microstructure to imprint the ultra-thin metal electrode 7 and the Ag nanowires to enhance the preferred surface microstructure;

[0095] S5: spin coating ZnO on the Ag nanowire at 3000 rpm for 40 seconds, and then performing annealing treatment, with the annealing temperature controlled at 150° C. for 15 minutes, to prepare a UV light absorbing layer 8;

[0096] S6: preparing an active layer solution doped with Au nanoparticles: PM6 and Y6 were mixed in a mass ratio of 1:1.2, 0.5 wt% Au nanoparticles were added, chloroform solvent and 0.5% by volume of chloronaphthalene additive were added to prepare a 16 mg / ml solution, and the solution was stirred and dissolved at 30°C and 600 rpm for 12 h;

[0097] S7: Spin-coating the active layer solution doped with Au nanoparticles on the ultraviolet light absorbing layer 8, controlling the rotation speed to be 2500 rpm, the spin-coating time to be 30 seconds, and then annealing at 110° C. for 10 minutes to obtain the active layer 5 doped with nanoparticles; and imprinting the active layer 5 doped with nanoparticles with a silicon template 11 etched with a preferred surface microstructure to enhance the preferred surface microstructure;

[0098] S8: Vacuum evaporation is used to deposit 5 nm of MoO on the nanoparticle-doped active layer 5 in an environment with a vacuum degree of less than 3.0×10-3Pa. 3 , an anode buffer layer 6 is prepared;

[0099] S9: placing the anode buffer layer 6 into a metal evaporation chamber, evaporating a 100 nm thick metal electrode Ag to prepare a thick metal electrode 3;

[0100] S10: Using the evaporation method, 100nm LiF and 30nm MoO are sequentially evaporated on the flexible substrate. 3 , repeat this operation twice to prepare a near-infrared DBR reflective layer 2, and then transfer the near-infrared DBR reflective layer 2 to the upper surface of the thick metal electrode 3, and finally obtain a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection.

[0101] like Figure 4 As shown, the working principle of the flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection of the bottom-incident structure in this embodiment is similar to that of the top-incident structure, except that in this structure, the ultraviolet light absorption layer 8 also has the function of cathode buffering. Since the carrier transmission distance is limited, in order to ensure the device efficiency, the ultraviolet light absorption layer 8 is set to 50nm here.

[0102] Under standard test, a beam is drawn from the light source so that the incident light 10 is irradiated on the device. In the range of 400-1100nm, the EQE reaches more than 70%, and the short-circuit current is 24.36mA / cm 2, open circuit voltage is 0.81V, fill factor is 0.72, efficiency reaches 12.8%, average visible light transmittance reaches 23.5%, UV reflectivity and dissipation rate are >85%, T under UV irradiation 80 Lifespan>4000 hours, near-infrared light reflectivity>94% at wavelength>1300nm, near-infrared light heating is slowed down by more than 78%.

[0103] The standard test conditions in the above embodiments 1 to 4 are: using a xenon lamp as a light source to simulate sunlight, air quality AM1.5, light intensity 100mW / cm 2 , the temperature is 25℃.

[0104] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, characterized in that: Including top-incident type structure and bottom-incident type structure; The top-incident structure comprises an ultraviolet DBR reflective layer, an ultraviolet light absorbing layer, an ultrathin metal electrode, an anode buffer layer, an active layer doped with nanoparticles, a cathode buffer layer, a thick metal electrode, a near-infrared DBR reflective layer and a flexible substrate, which are arranged in sequence from top to bottom; the flexible substrate, the near-infrared DBR reflective layer, the thick metal electrode, the cathode buffer layer, the active layer doped with nanoparticles, the anode buffer layer, the ultrathin metal electrode and the ultraviolet light absorbing layer all have surface microstructures; In the nanoparticle-doped active layer, the active layer material is a bulk heterojunction structure mixed film or a perovskite film, and the nanoparticles include graphene quantum dots, carbon nanotubes, gold nanoparticles, silver nanoparticles, silicon nanoparticles or nickel nanoparticles, with a size of 10 to 70 nm; The bottom-incident structure comprises a flexible substrate, an ultraviolet DBR reflective layer, an ultrathin metal electrode, an ultraviolet light absorbing layer, a nanoparticle-doped active layer, an anode buffer layer, a thick metal electrode and a near-infrared DBR reflective layer, which are arranged in sequence from bottom to top; the flexible substrate, the ultraviolet DBR reflective layer, the ultrathin metal electrode, the ultraviolet light absorbing layer, the nanoparticle-doped active layer, the anode buffer layer and the thick metal electrode all have surface microstructures; A metal microcavity structure is formed between the thick metal electrode and the ultra-thin metal electrode of the top-incident structure and the bottom-incident structure, and a metal nanowire is arranged on the upper surface of the ultra-thin metal electrode. The metal nanowire is made of Ag and has a thickness of 10 to 15 nm.

2. The flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection according to claim 1, characterized in that: The thickness of the active layer doped with nanoparticles is 100-250 nm, and the doping concentration of the nanoparticles is 0.5 wt %-2 wt %.

3. The flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection according to claim 1, characterized in that: The near-infrared DBR reflective layer includes (LiF / MoO3) n 、(CA / PVK) m or (PAA / PVK) l ; Among them, n, m and l are the number of film layers, n is 1 or 2, m is 40-43, and l is 40-43; the thickness of single-layer LiF and MoO3 are 100-120nm and 60-120nm respectively; the thickness of single-layer CA and PVK are 220-330nm and 200-295nm respectively; the thickness of single-layer PAA and PVK are 160-240nm and 140-210nm respectively.

4. The flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection according to claim 1, characterized in that: The thick metal electrode and the ultra-thin metal electrode are both made of Ag, and have thicknesses of 100 nm and 6 nm respectively.

5. The flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection according to claim 1, characterized in that: The UV DBR reflective layer (Ta2O5 / SiO2) p 、(SiO2 / YDH) q or (TiO2 / SiO x ) k ; Among them, p, q and k are the number of film layers, p is 31, q is 10-15, k is 6 or 7; the thickness of single-layer Ta2O5 and SiO2 is 181nm and 302nm respectively; the thickness of single-layer SiO2 and YDH is 30nm and 29nm respectively; the thickness of single-layer TiO2 and SiO x The thicknesses are 30nm and 70nm respectively.

6. The flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection according to claim 1, characterized in that: The surface microstructure is cylindrical or polygonal in shape, with a size of 200 to 500 nm and a height of 5 to 20 nm.

7. The flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection according to claim 1, characterized in that: The shape and size of the surface microstructure, the shape and size of the nanoparticles, and the thickness of the near-infrared DBR reflective layer and the ultraviolet DBR reflective layer are determined by optical transmission matrix and finite element analysis theoretical simulation.

8. The flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection according to claim 1, characterized in that: The cathode buffer layer includes ZnO, TiO2, SnO2, PEIE, PC 61 BM or PC 71 BM, thickness is 30~50nm; anode buffer layer includes MoO3, CuSCN, V2O5, NiO x , WO3, PANI, PEDOT:PSS, TAPC, Spiro-OMeTAD or PTAA, with a thickness of 5nm; the UV light absorption layer includes ZnO x 、TiO x Or TeO2, the thickness of the ultraviolet light absorbing layer in the top-incident structure is 1 μm, and the thickness of the ultraviolet light absorbing layer in the bottom-incident structure is 50 nm.

9. A method for preparing a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection, characterized in that: The flexible microcavity solar cell is a top-incident structure, and the preparation method comprises the following steps: SA1: Based on the optical transmission matrix and finite element analysis theory, an optical simulation model of surface microstructure and nanoparticle doping is constructed. Light field simulation is performed for different incident light wavelengths to obtain the influence of the shape and size of the surface microstructure, as well as the shape and size of the nanoparticles on the wavelength range and local enhancement rate of the plasma effect, and then the preferred surface microstructure and preferred nanoparticles corresponding to the wavelength of the incident light are selected; at the same time, according to the materials of the near-infrared DBR reflective layer and the ultraviolet DBR reflective layer used, the specific thickness and number of layers are determined through optical transmission matrix theoretical simulation; SA2: A silicon template with a preferred surface microstructure etched on it is used to emboss the preferred surface microstructure on a flexible substrate; SA3: A near-infrared DBR reflective layer and a thick metal electrode are sequentially prepared on a flexible substrate, and the thick metal electrode is imprinted with a silicon template etched with a preferred surface microstructure to enhance the preferred surface microstructure; SA4: a cathode buffer layer and an active layer doped with preferred nanoparticles are sequentially prepared on a thick metal electrode, and the active layer doped with preferred nanoparticles is imprinted with a silicon template etched with a preferred surface microstructure to enhance the preferred surface microstructure; SA5: An anode buffer layer, an ultrathin metal electrode, a metal nanowire and a UV absorption layer are sequentially prepared on the nanoparticle-doped active layer, and then a UV DBR reflection layer is prepared on a flexible substrate. The UV DBR reflection layer is then transferred to the upper surface of the UV absorption layer, and finally a flexible microcavity solar cell with long-wave near-infrared and UV reflection is obtained; The flexible microcavity solar cell is a bottom-incident structure, and the preparation method comprises the following steps: SB1: Based on the optical transmission matrix and finite element analysis theory, an optical simulation model of surface microstructure and nanoparticle doping is constructed. Light field simulation is performed for different incident light wavelengths to obtain the influence of the shape and size of the surface microstructure, as well as the shape and size of the nanoparticles on the wavelength range of the plasma effect and the local enhancement rate, and then the preferred surface microstructure and preferred nanoparticles corresponding to the wavelength of the incident light are selected; at the same time, according to the materials of the near-infrared DBR reflective layer and the ultraviolet DBR reflective layer used, the specific thickness and number of layers are determined through optical transmission matrix theoretical simulation; SB2: Using a silicon template etched with a preferred surface microstructure, the preferred surface microstructure is imprinted on a flexible substrate; SB3: A UV DBR reflective layer, an ultrathin metal electrode and metal nanowires are sequentially prepared on a flexible substrate and imprinted with a silicon template etched with a preferred surface microstructure to enhance the preferred surface microstructure; SB4: sequentially preparing an ultraviolet light absorbing layer and an active layer doped with preferred nanoparticles on the metal nanowires, and imprinting the active layer doped with preferred nanoparticles with a silicon template etched with a preferred surface microstructure to enhance the preferred surface microstructure; SB5: An anode buffer layer and a thick metal electrode are sequentially prepared on the nanoparticle-doped active layer, and then a near-infrared DBR reflective layer is prepared on a flexible substrate. The near-infrared DBR reflective layer is then transferred to the upper surface of the thick metal electrode, and finally a flexible microcavity solar cell with long-wave near-infrared and ultraviolet light reflection is obtained.

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