Nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cell and low-temperature preparation method and application of nickel oxide thin layer

Abstract

The invention discloses a spectrum conversion and hole transport dual-function nickel oxide thin layer for a solar cell and a low-temperature preparation method and application thereof, and belongs to the technical field of light conversion materials. The low-temperature preparation method comprises the following steps: S1, dissolving rare earth nitrate and nickel acetate in an organic solvent, heating in a water bath, violently stirring, and then aging for at least 24 hours to form a sol-gel system; s2, spin-coating a sol-gel system on the cleaned substrate and drying the sol-gel system; s3, the spin-coated thin film is subjected to ultraviolet ozone irradiation treatment for 1-3 h; and irradiating for 0.5-2 hours by using a 1100nm halogen short-wave near-infrared lamp to obtain the nickel oxide thin layer with double functions of spectrum conversion and hole transmission for the solar cell. According to the method, the nickel oxide can present the crystallization characteristic without high-temperature treatment, the substrate can be protected, NiO film deposition of the substrate which is not resistant to high temperature is realized, and the stress of a bonding interface of NiO and the substrate after being heated is reduced.

Description

Technical Field

[0001] The invention relates to a nickel oxide thin layer with dual functions of spectrum conversion and hole transmission for solar cells and a low-temperature preparation method and application thereof, belonging to the technical field of light conversion materials. Background Art

[0002] As a commonly used hole transport layer (HTL), NiO (nickel oxide) plays an important role in photovoltaic devices such as perovskite solar cells, dye-sensitized solar cells, and other types of optoelectronic devices. As a p-type semiconductor, NiO can effectively extract holes from the active layer (such as the perovskite layer) and transfer them to the anode, thereby improving the overall efficiency of the device. The NiO layer can also improve the contact between the active layer and the anode, reduce non-radiative recombination at the interface, and improve the charge separation efficiency.

[0003] The hole transport layer is assembled with the solar cell and placed on the back of the cell. In actual application, the back of the cell does not absorb sunlight. However, for thin-film or thin silicon cells, the front absorption layer of the cell cannot absorb and convert all the spectrum, especially the infrared long-wave photons will penetrate the absorption layer of the cell to reach the hole transport layer on the back. If the hole transport layer also has the function of spectrum conversion, it can convert infrared light into visible light and continue to be reversely absorbed by the absorption layer. Therefore, there is an urgent need for a thin nickel oxide layer with dual functions of spectrum conversion and hole transport for solar cells.

[0004] At present, the commonly used hole transport layer of solar cells is transition metal oxide, especially nickel oxide, which is the most mature. However, there are still some practical problems that need to be solved, such as the problem of crystal control: different crystal orientations of NiO will affect the hole transport capacity and transmittance. How to control the crystal growth and regulate the electrical and optical properties is a technical problem. In addition, the conductivity of pure NiO film is low, and a small amount of elements need to be doped. The addition of doping elements has a significant effect on the lattice. How to select doping elements and balance the mutual constraints between lattice distortion and conductivity improvement also tests the existing preparation technology. Rare earth-doped films require calcination at a temperature above 600°C or high-pressure synthesis to have spectral conversion function. At the same time, the preparation of high-quality NiO films usually requires a high-temperature annealing process, which not only increases the production cost, but also limits the possibility of its large-scale application.

[0005] Effective ways to improve the photoelectric conversion efficiency of solar cells include improving the hole transport efficiency and increasing the light absorption rate. Usually, these two methods require stacking two thin films on the solar cell (a high-performance hole transport layer and a spectrum conversion film), which increases the process and cost, and also increases the difficulty of preparation.

[0006] The NiO film prepared by the present invention has good chemical stability and thermal stability, adjustable crystal plane orientation, high transmittance in the visible light region, and can achieve high conductivity and effective spectrum conversion function through doping and low temperature treatment. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a nickel oxide thin layer with dual functions of spectral conversion and hole transport for solar cells, which can improve the crystal quality, uniformity and compactness of the doped NiO film, reduce the resistivity and increase the carrier transfer efficiency; and add another function of the hole transport layer - spectral conversion: converting the infrared or ultraviolet bands that cannot be absorbed by the solar cell into the visible light band with high absorption rate, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0008] At the same time, the present invention provides a low-temperature preparation method of a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells.

[0009] At the same time, the present invention provides an application of a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0011] A low-temperature preparation method for a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells comprises the following steps:

[0012] S1, dissolving 1-10 mmol of rare earth nitrate and 5-50 mmol of nickel acetate in 50-500 mL of a polar organic solvent and a weakly polar organic solvent, respectively, heating in a water bath at 50-90° C. and vigorously stirring for more than 1 h at a stirring rate of 800-1200 r / min, and then aging for at least 24 h to form a sol-gel system;

[0013] S2, spin coating the sol-gel system on the cleaned substrate and drying at 100-200° C.; repeating this step 5-10 times to form a thin film with a thickness in the range of 200-400 nm.

[0014] S3, the spin-coated film is first subjected to ultraviolet ozone irradiation treatment for 1 to 3 hours, the ultraviolet wavelength is 200nm, and the irradiation power is 20-60W / cm 2 , ozone concentration 2-8ppm; then irradiate with 1100nm halogen short-wave near-infrared lamp for 0.5-2h, power 1200-2000W, to obtain a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells.

[0015] Preferably, the rare earth nitrate comprises erbium nitrate, lanthanum nitrate, terbium nitrate, ytterbium nitrate, yttrium nitrate, cerium nitrate or scandium nitrate.

[0016] Preferably, the polar organic solvent includes methanol and 1-4-butanediol.

[0017] Preferably, the weakly polar organic solvent includes ethanol and 2-propanol.

[0018] Preferably, the substrate comprises glass, quartz, a silicon wafer, a plastic sheet or a perovskite film.

[0019] Preferably, the substrate is a substrate that has been cleaned according to standard procedures.

[0020] A nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells, the resistivity of the thin layer is 177.6-370.6Ω·cm, and the mobility is 0.24-0.40cm 2 / V·s, and the carrier concentration is 1.9×10 16 ~3.0×10 16 cm -3 .

[0021] The invention discloses an application of a nickel oxide thin layer having dual functions of spectrum conversion and hole transport for solar cells in a photovoltaic device.

[0022] Preferably, the photovoltaic device comprises a perovskite solar cell or a dye-sensitized solar cell.

[0023] A photovoltaic device is prepared by using the nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells of the present invention.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention mainly solves the following problems: ① Improve the crystal quality, uniformity and compactness of the doped NiO film, reduce the resistivity and increase the carrier transfer efficiency. ② Add another function of the hole transport layer - spectrum conversion: convert the infrared or ultraviolet bands that the solar cell cannot absorb into the visible light band with high absorption rate, further improving the photoelectric conversion efficiency of the solar cell.

[0026] The present invention discloses a method for preparing a nickel oxide hole transport layer at a low temperature, which can make the nickel oxide present crystalline characteristics without high temperature treatment, can protect the substrate, realize NiO film deposition on a substrate that is not resistant to high temperatures, and reduce the stress at the interface between NiO and the substrate after heating.

[0027] The present invention is also a preparation method with controllable conductivity, carrier concentration and mobility, and the preferred orientation of the film can be adjusted by adding different solvents.

[0028] The present invention obtains a NiO film having both spectrum conversion function and hole transport function and a preparation method thereof, and the spectrum conversion function can be regulated by adding rare earth salts.

[0029] The present invention is simple and controllable, and can adopt the existing spin coating method to realize nickel oxide films with different preferred orientations and functions by adjusting the solvent type and solute concentration of the spin coating solution, and adjust the electrical properties of the NiO film by regulating the preferred orientation.

[0030] The present invention can form a crystalline film without high-temperature heat treatment, thereby avoiding damage to the substrate after being heated or internal stress at the interface between the substrate and the film, and can realize the growth of NiO films on all substrates.

[0031] The substrate for depositing the thin film of the present invention is not limited to glass or quartz, but may also be a silicon wafer, a plastic sheet, a substrate for depositing other materials (such as perovskite thin film, etc.), etc., which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a preparation flow chart of the present invention;

[0033] Figure 2 The morphology of the samples tested by the scanning electron microscope of the present invention, wherein, (a) SEM images of A7-B, (b) UV-B, (c) IR-B, (d) UVIR-B samples;

[0034] Figure 3 is the X-ray diffraction analysis diagram of the present invention;

[0035] Figure 4 For the present invention 3+ Upconversion luminescence spectrum of doped NiO thin film. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0037] Example 1

[0038] A low-temperature preparation method for a thin nickel oxide layer with dual functions of spectrum conversion and hole transport for solar cells, the preparation process is as follows Figure 1 As shown:

[0039] ① Dissolve 2 mmol of rare earth (RE) nitrate (i.e., erbium nitrate) and 10 mmol of nickel acetate in 50 mL of different types of organic solvents (methanol, ethanol, 2-propanol, 1-4-butanediol), heat in a 70°C water bath and stir vigorously (stirring rate is 1000 r / min) for 1 h to fully stir, and then age for 24 h to form a sol-gel system.

[0040] ② Spin-coat the sol-gel on a glass or quartz substrate with a length and width of 30 mm and a thickness of 3 mm that has been cleaned according to the standard process and dry it at 100°C. Repeat this step 8 times to form a film with a thickness of about 300 nm. According to the different sol solvents (methanol, ethanol, 2-propanol, 1-4-butanediol), the samples are labeled as A, B, C, and D, and multiple of the same sample are prepared.

[0041] Among them, A represents the sol solvent is methanol, B represents the sol solvent is ethanol, C represents the sol solvent is 2-propanol, and D represents the sol solvent is 1-4-butanediol.

[0042] ③ A portion of the spin-coated film was irradiated with ultraviolet ozone for 3 h (ultraviolet wavelength 200 nm, irradiation power 40 W / cm 2 , ozone concentration 5ppm), the sample was recorded as UV-X, one part was irradiated with 1100nm halogen shortwave near-infrared lamp for 1h (power 1200W), the sample was recorded as IR-X, one part was annealed at 500 / 700 / 900℃ in air atmosphere for 1h, the sample was recorded as A5 / 7 / 9-X, and the last part was treated with ultraviolet ozone irradiation for 3h + 1100nm halogen shortwave near-infrared lamp irradiation for 1h, the sample was recorded as UVIR-X (X represents A, B, C, D).

[0043] Scanning electron microscope test sample morphology ( Figure 2 ), UV-X, IR-X, and A7-X samples all show a continuous film composed of crystalline particles, indicating that both ultraviolet irradiation and infrared irradiation can achieve the purpose of high-temperature annealing, that is, to enable the NiO film to obtain energy to continue growing and present a crystalline state. During the ultraviolet ozone irradiation treatment, the synergistic effect of ultraviolet light and ozone excites ozone molecules through ultraviolet light to generate highly active oxygen atoms, which in turn react with the NiO prefabricated layer to trigger the oxidation process and promote the oxidation crystallization of NiO, thereby optimizing the surface properties of the material. Near-infrared irradiation can accurately transfer heat to the film, achieving high-temperature crystallization and activation of rare earth ions only at the film level. From Figure 2 It can be seen that the film area of ​​the A7-X sample has larger cracks and is not as dense as the film treated with UV and infrared radiation. This is because high-temperature treatment will cause the prefabricated film and the substrate to heat up at the same time. Due to the different thermal expansion coefficients of the two, the bonding force between the film and the substrate becomes worse, micro cracks appear in the film, and the density decreases. Therefore, UV and infrared irradiation can accurately transfer photon energy to the film without heating the substrate, thereby realizing the low-temperature preparation of crystalline NiO film. Figure 2 (d) The film has a denser structure and relatively larger grains. This is because the UV-ozone irradiation treatment improves the oxygen content and crystallinity of the nickel oxide film. The subsequent infrared irradiation treatment produces local high temperatures, which continue to promote the diffusion of Ni ions and rare earth ions, further increasing the growth of grains.

[0044] The crystal orientation properties of samples with four different post-treatment methods were analyzed by X-ray diffraction, such as Figure 3 (a) shows that all samples showed NiO crystal state, and the peak values ​​of UVIR treatment were all higher. Combined with the scanning images, it further shows that UV-ozone irradiation plus infrared irradiation achieved the best crystallization degree. Taking the samples treated with UV-ozone irradiation plus infrared irradiation as an example, X-ray diffraction was used to test the crystal plane orientation of samples prepared with different solvents, such as Figure 3 As shown in (b). UVIR-A and UVIR-D samples show preferential growth on the (111) crystal plane, while UVIR-B and UVIR-C samples show preferential growth on the (200) crystal plane. This rule also applies to samples treated with infrared irradiation and high-temperature annealing. This is because methanol, 1-4-butanediol and other organic solvents are highly polar and are preferentially adsorbed by the polar crystal plane (111) of NiO during growth, while organic solvents such as ethanol and 2-propanol have lower polarity and are preferentially adsorbed by the non-polar crystal plane (200) of NiO, so they show preferential growth on the (200) crystal plane. This conclusion can effectively control the preferential growth of NiO crystal structure and achieve controllable preparation.

[0045] Table 1 shows the conductivity, carrier concentration, mobility and other tests of different samples using a Hall effect tester, proving that different subsequent treatments and preferential growth of crystal plane orientations affect the electrical properties of NiO thin films. The sample treated with both UV ozone irradiation and infrared irradiation (UVIR-B) has the lowest resistivity compared with the samples treated with other methods, because better film density and larger grain size are conducive to carrier migration, and precise heating during the preparation process increases the carrier concentration, and the two work together to reduce the resistivity of the film. At the same time, the samples prepared by this method have higher carrier mobility, which is conducive to the use of nickel oxide as a hole transport layer. The preferential growth of polar crystal planes increases the directional transmission rate of carriers, but reduces the carrier concentration; while the preferential growth of non-polar crystal planes increases the carrier concentration, but reduces the carrier transmission rate. The mutual influence of the two results in the overall resistivity showing low polar orientation resistivity and high non-polar orientation resistivity. This controllable preparation provides help for the optimization of the selective hole transport layer, and the optimized preparation of the NiO hole transport layer can be carried out according to the parameter changes of carrier concentration and transmission rate.

[0046] Table 1 Electrical properties of samples

[0047]

[0048] The beneficial performance of doping with rare earth elements is that the film layer has up-down conversion function. Taking the doping with erbium nitrate as an example, Figure 4 Er under 980nm laser irradiation and different subsequent treatments 3+Upconversion luminescence spectrum of doped NiO film. When the Er doping concentration is fixed at 5%, there is no upconversion luminescence spectrum at air annealing at 500℃ and 700℃, and it is not until the annealing temperature reaches 900℃ that there is a relatively strong upconversion performance. The sample treated with UV-ozone irradiation also has no upconversion effect, and the sample treated with infrared irradiation has a slight green light region (G1 / G2) luminescence. Finally, the sample treated with UV-ozone irradiation plus infrared irradiation has a strong upconversion luminescence in the green and red (R) regions, and the intensity is even stronger than that of high-temperature annealing at 900℃. This is because rare earth ions (Er 3+ ) After entering the matrix material (NiO), it needs to be activated by energy to have the ability to convert spectra, and the transmission of photons inside the material requires good crystal quality. Usually, energy and good crystal quality are provided by high temperature, so the activation of rare earth ions requires high temperature (above 700°C) or high pressure, but high temperature and high pressure have considerable damage to film formation on the device, and new ways must be found to have enough energy to activate rare earth ions without damaging existing devices. Ultraviolet ozone irradiation can promote the crystallization of thin films under low temperature conditions, but it cannot provide sufficient ability to activate rare earth ions, and simple infrared irradiation has no effect on filling the oxygen vacancies in the film grains, and the transmission of light by rare earth ions is limited. Only after the oxygen content is supplemented and the crystal quality of the film is improved by ultraviolet ozone irradiation, and then infrared irradiation is used to accurately provide energy to the rare earth ions, the spectral conversion effect of the rare earth ions can be activated. The present invention can realize low-temperature preparation of NiO thin film after ultraviolet ozone irradiation plus infrared irradiation treatment, and the film can be used as a hole transport layer to have the dual functions of hole transport and spectrum conversion, thereby providing further guarantee for the improvement of the photoelectric conversion efficiency of solar cells.

[0049] A nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells is obtained by the low-temperature preparation method of this embodiment.

[0050] The solar cell of this embodiment uses a nickel oxide thin layer with dual functions of spectrum conversion and hole transport in a photovoltaic device.

[0051] Photovoltaic devices include perovskite solar cells and dye-sensitized solar cells.

[0052] A photovoltaic device is prepared by using the nickel oxide thin layer with dual functions of spectrum conversion and hole transport for the solar cell of this embodiment.

[0053] Example 2

[0054] A low-temperature preparation method for a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells comprises the following steps:

[0055] ① Dissolve 1 mmol of lanthanum nitrate and 5 mmol of nickel acetate in 100 mL of methanol, heat in a 50°C water bath and stir vigorously (stirring rate is 800 r / min) for 1.5 h to fully stir, then age for 30 h to form a sol-gel system.

[0056] ② Spin-coat the sol-gel on a silicon wafer substrate with a length and width of 30 mm and a thickness of 3 mm that has been cleaned according to the standard process and dry it at 150°C. Repeat this step 5 times to form a thin film with a thickness of about 200 nm.

[0057] ③ The spin-coated film is irradiated with ultraviolet ozone for 1 hour + 1100nm halogen short-wave near-infrared lamp for 0.5 hour. The spin-coated film is first irradiated with ultraviolet ozone for 1 hour, with an ultraviolet wavelength of 200nm and an irradiation power of 20W / cm 2 , ozone concentration 2ppm; then irradiate with 1100nm halogen shortwave near-infrared lamp for 0.5h, power 1500W, to obtain a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells.

[0058] A nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells is obtained by the low-temperature preparation method of this embodiment.

[0059] The solar cell of this embodiment uses a nickel oxide thin layer with dual functions of spectrum conversion and hole transport in a photovoltaic device.

[0060] Photovoltaic devices include perovskite solar cells and dye-sensitized solar cells.

[0061] A photovoltaic device is prepared by using the nickel oxide thin layer with dual functions of spectrum conversion and hole transport for the solar cell of this embodiment.

[0062] Example 3

[0063] A low-temperature preparation method for a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells comprises the following steps:

[0064] ① Dissolve 10 mmol of terbium nitrate and 50 mmol of nickel acetate in 500 mL of 2-propanol, heat in a 90°C water bath and stir vigorously (stirring rate is 1200 r / min) for 2 h to fully stir, and then age for 36 h to form a sol-gel system.

[0065] ② Spin-coat the sol-gel on a plastic sheet substrate with a length and width of 30 mm and a thickness of 3 mm that has been cleaned according to the standard process and dry it at 200°C. Repeat this step 10 times to form a film with a thickness of about 400 nm.

[0066] ③ The spin-coated film is irradiated with ultraviolet ozone for 2 hours + 1100nm halogen short-wave near-infrared lamp for 2 hours. The spin-coated film is first irradiated with ultraviolet ozone for 2 hours, with an ultraviolet wavelength of 200nm and an irradiation power of 60W / cm 2 , ozone concentration 8ppm; then irradiate with 1100nm halogen short-wave near-infrared lamp for 2h, power 2000W, to obtain a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells.

[0067] A nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells is obtained by the low-temperature preparation method of this embodiment.

[0068] The solar cell of this embodiment uses a nickel oxide thin layer with dual functions of spectrum conversion and hole transport in a photovoltaic device.

[0069] Photovoltaic devices include perovskite solar cells and dye-sensitized solar cells.

[0070] A photovoltaic device is prepared by using the nickel oxide thin layer with dual functions of spectrum conversion and hole transport for the solar cell of this embodiment.

[0071] Comparative Example 1

[0072] The method for preparing a nickel oxide thin layer comprises the following steps:

[0073] Step 1, preparation of precursor solution: dissolving nickel salt (such as nickel nitrate) and rare earth salt (such as lanthanum nitrate, yttrium nitrate or scandium nitrate) in water to prepare a precursor solution.

[0074] Step 2, precipitation generation: a sodium hydroxide solution of a certain concentration (10-30 mg / ml) is added dropwise to the above precursor solution until the pH value of the solution is adjusted to between 9.5 and 10.5, during which a precipitate will be precipitated.

[0075] Step 3, washing and drying the precipitate: the precipitate generated in step 2 is washed three times with deionized water and anhydrous ethanol alternately, and then dried in a vacuum drying oven at 25° C. to obtain rare earth-doped nickel hydroxide.

[0076] Step 4, calcination process: the rare earth-doped nickel hydroxide obtained in step 3 is placed in a muffle furnace, heated to 275°C at a heating rate of 10°C / min in an air atmosphere, and maintained for 2 hours of calcination, and then cooled to room temperature to obtain rare earth-doped nickel oxide.

[0077] Step 5, dispersion and spin coating: the rare earth-doped nickel oxide obtained in step 4 is dispersed in water and ultrasonically treated for 10 minutes (ultrasonic power 40kHz), then filtered through a filter membrane with a pore size not greater than 0.45μm, and finally the filtered dispersion is spin-coated on an ITO substrate and annealed at 100°C for more than 5 minutes.

[0078] The nickel oxide thin layer obtained in this comparative example requires high temperature to be obtained.

[0079] Comparative Example 2

[0080] The method for preparing the thin layer comprises the following steps:

[0081] (1) Add ErF3 powder to YbF3 powder, wherein the molar fraction of ErF3 powder is 0.5% to 15%, then mix by ball milling, dry and press into tablets, and then burn at 600 to 750°C for 6 to 8 hours by carbon coating to form a ceramic target.

[0082] (2) Using the YbF3: Er ceramic target prepared by the above method, a thin film material is prepared by electron beam deposition; using silicon wafer or quartz as the substrate, under vacuum conditions, the substrate temperature is 400-500°C, the target spacing is 32 cm, the deposition beam current is 6 mA, and the deposition time is 15 min to 90 min.

[0083] The spectrum conversion film obtained in this comparative example also requires high temperature.

[0084] It should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in less than all of the features of the previously disclosed embodiments. Therefore, the claims that follow the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present invention.

[0085] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

[0086] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-temperature preparation method for a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells, characterized in that: The following steps are involved: S1, dissolving 1-10 mmol of rare earth nitrate and 5-50 mmol of nickel acetate in 50-500 mL of a polar organic solvent and a weakly polar organic solvent, respectively, heating in a water bath at 50-90° C. and vigorously stirring for more than 1 h at a stirring rate of 800-1200 r / min, and then aging for at least 24 h to form a sol-gel system; S2, spin coating the sol-gel system on the cleaned substrate and drying at 100-200°C; S3, the spin-coated film is first subjected to ultraviolet ozone irradiation treatment for 1 to 3 hours, the ultraviolet wavelength is 200nm, and the irradiation power is 20-60W / cm 2 , ozone concentration 2-8ppm; then irradiate with 1100nm halogen short-wave near-infrared lamp for 0.5-2h, power 1200-2000W, to obtain a nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells.

2. The low temperature preparation method according to claim 1, characterized in that: The rare earth nitrate includes erbium nitrate, lanthanum nitrate, terbium nitrate, ytterbium nitrate, yttrium nitrate, cerium nitrate or scandium nitrate.

3. The low temperature preparation method according to claim 1, characterized in that: Polar organic solvents include methanol and 1-4-butanediol.

4. The low temperature preparation method according to claim 1, characterized in that: Weakly polar organic solvents include ethanol and 2-propanol.

5. The low temperature preparation method according to claim 1, characterized in that: The substrate includes glass, quartz, silicon wafer, plastic sheet or perovskite film.

6. The low temperature preparation method according to claim 1, characterized in that: The substrate is cleaned according to the standard process.

7. The nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells obtained by the low-temperature preparation method according to any one of claims 1 to 6, characterized in that: The resistivity of the thin layer is 177.6~370.6Ω·cm, and the mobility is 0.24~0.40cm 2 / V·s, and the carrier concentration is 1.9×10 16 ~3.0×10 16 cm -3 .

8. Application of the nickel oxide thin layer with dual functions of spectrum conversion and hole transport for solar cells according to claim 7 in photovoltaic devices.

9. The use according to claim 8, characterized in that: Photovoltaic devices include perovskite solar cells and dye-sensitized solar cells.

10. A photovoltaic device, characterized in that: The solar cell is prepared by using the nickel oxide thin layer with dual functions of spectrum conversion and hole transport as described in claim 7.

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