WO2023109712A1 - Wide bandgap copper-gallium-selenium light absorption layer and preparation method therefor, and solar cell - Google Patents

Wide bandgap copper-gallium-selenium light absorption layer and preparation method therefor, and solar cell Download PDF

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WO2023109712A1
WO2023109712A1 PCT/CN2022/138204 CN2022138204W WO2023109712A1 WO 2023109712 A1 WO2023109712 A1 WO 2023109712A1 CN 2022138204 W CN2022138204 W CN 2022138204W WO 2023109712 A1 WO2023109712 A1 WO 2023109712A1
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gallium
copper
selenium
substrate
temperature
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Chinese (zh)
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童佩斐
李文杰
李国啸
陈志勇
刘旭辉
杨春雷
冯叶
钟国华
邵龑
李伟民
陈明
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深圳先进技术研究院
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/032—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
    • H01L31/0322—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier
    • H01L31/072—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier the potential barriers being only of the PN heterojunction type
    • H01L31/0749—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier the potential barriers being only of the PN heterojunction type including a AIBIIICVI compound, e.g. CdS/CulnSe2 [CIS] heterojunction solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/186—Particular post-treatment for the devices, e.g. annealing, impurity gettering, short-circuit elimination, recrystallisation
    • H01L31/1864—Annealing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/541—CuInSe2 material PV cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the invention belongs to the technical field of solar cells, and in particular relates to a wide-bandgap copper-gallium-selenium light-absorbing layer and a preparation method thereof, and also relates to a solar cell comprising the wide-bandgap copper-gallium-selenium light-absorbing layer.
  • Tandem solar cells can connect absorbing layers matching different spectral bands in series to increase the absorption width of the solar spectrum.
  • the absorption layers of different bandgap widths of tandem solar cells absorb photons of different energies, which can reduce the thermal relaxation loss caused by the excess energy of high-energy photons beyond the bandgap width, and maximize the conversion of light energy into electrical energy, thereby greatly improving Photoelectric conversion efficiency.
  • the mainstream double-junction tandem cell in tandem cells requires a bottom cell with a narrow bandgap and a top cell with a wide bandgap.
  • top cell materials for wide bandgap are scarce.
  • the top cell material is required to have a bandgap of 1.6
  • III-V materials are the only choice for a long period of time. Finding high-efficiency, low-cost p-type wide-bandgap top cell materials is the key to the future development of double-junction stacked cells.
  • the band gap of CIGS can be flexibly adjusted in the range of 1.0-2.5 eV.
  • CIGS copper indium gallium selenide
  • the most efficient CIGS solar cell has a band gap of 1.15eV and a corresponding Ga/Ga+In ratio of 0.3.
  • the current mainstream research direction in the world is to replace cations and anions.
  • cation replacement it is mainly to increase the Ga component content to increase the absorption band gap of CIGS materials. If all In in CuInGaSe 2 is replaced by Ga to form copper gallium selenide (CGSe), the forbidden band width of CGSe can reach 1.7eV.
  • CGSe copper gallium selenide
  • ODC layer ordered defect reconstruction layer
  • This structure has a fixed lattice structure and energy band structure, which can greatly reduce the recombination probability of carriers at the crystal interface.
  • In and Cu antisite defects there are a large number of In and Cu antisite defects in this ordered defect reconstruction layer.
  • all In in CuInGaSe 2 is replaced by Ga.
  • the above-mentioned ordered defect reconstruction layer is difficult Formed at the interface, it cannot inhibit the electron-hole recombination at the surface and crystal interface, which reduces the battery efficiency.
  • the present invention provides a wide-bandgap copper-gallium-selenide light-absorbing layer and its preparation method, and a solar cell to solve the problem of battery efficiency in the prior art in order to obtain copper-gallium-selenide with a high bandgap width. Lowering the problem.
  • a wide bandgap copper gallium selenide light absorbing layer comprising a copper gallium selenide thin film layer and an indium gallium thin film layer covered on the copper gallium selenide thin film layer, the copper gallium selenide thin film layer and the indium gallium selenide thin film layer
  • the interface with InCu antisite defects was formed through an annealing process.
  • the atomic ratio of gallium to the sum of indium and gallium in the indium gallium thin film layer is (0.3-0.7):1.
  • the atomic ratio of gallium to the sum of indium and gallium in the indium gallium thin film layer is (0.5-0.7):1.
  • the thickness of the wide bandgap copper gallium selenide light absorbing layer is 1.0 ⁇ m to 3.0 ⁇ m.
  • the present invention also provides a method for preparing the wide-bandgap copper-gallium-selenium light-absorbing layer as described above, comprising the following steps:
  • the atomic ratio of gallium to the sum of indium and gallium is controlled to be (0.3-0.7):1.
  • the atomic ratio of gallium to the sum of indium and gallium is controlled to be (0.5-0.7):1.
  • the annealing time of the annealing treatment is 15 minutes to 20 minutes.
  • the first temperature is 340°C-380°C
  • the second temperature is 500°C-600°C.
  • the substrate contains a molybdenum metal layer.
  • selenium vapor is first introduced to form a molybdenum selenide layer on the surface of the molybdenum metal layer, and then gallium vapor is introduced to form a molybdenum selenide layer.
  • gallium and selenium are co-evaporated on the molybdenum selenide layer.
  • An embodiment of the present invention also provides a solar cell, which includes the above-mentioned wide bandgap copper gallium selenide light absorbing layer.
  • the wide bandgap copper gallium selenium light absorbing layer and its preparation method provided by the embodiments of the present invention are based on the traditional three-step co-evaporation process for preparing copper indium gallium selenide, and replace In with Ga in the first step of co-evaporation.
  • the third step of co-evaporation re-introduces In, and covers the copper gallium selenide film layer with rich In Indium Gallium thin film layer, and then through the annealing process, the interface between the CuGaSe thin film layer and the InGa thin film layer has In Cu antisite defects, and a restructured phase that is conducive to charge separation and inhibits interface recombination is formed at the crystal interface.
  • the copper-gallium-selenide light-absorbing layer thus obtained can obtain higher-efficiency solar cells on the basis of having a wide bandgap, and can be better suitable for tandem solar cells.
  • Fig. 1 is the structural representation of the thin-film solar cell prepared in the embodiment of the present invention.
  • Fig. 2 is the flowchart of the preparation method of the wide bandgap copper gallium selenide light absorbing layer in the embodiment of the present invention
  • Fig. 3 is the SEM sectional view of the bandgap copper gallium selenide photoabsorbing layer prepared in the embodiment of the present invention.
  • Fig. 4 is a graph of voltammetry of the thin film solar cell prepared in the embodiment of the present invention.
  • the embodiment of the present invention firstly provides a wide bandgap copper gallium selenide light absorbing layer, comprising a copper gallium selenide thin film layer and an indium gallium thin film layer covered on the copper gallium selenide thin film layer, the copper gallium selenide thin film layer In the interface with the indium gallium thin film layer, an In Cu antisite defect is formed through an annealing process, and a restructured phase structure that is beneficial to charge separation and inhibits interface recombination is formed at the crystal interface.
  • the atomic ratio of gallium to the sum of indium and gallium (Ga/Ga+In) in the indium gallium thin film layer is (0.3 ⁇ 0.7):1, and a more preferable ratio is (0.5 ⁇ 0.7): 1.
  • the thickness of the wide bandgap copper gallium selenide light absorbing layer is 1.0 ⁇ m to 3.0 ⁇ m.
  • the embodiment of the present invention also provides a method for preparing the wide bandgap copper gallium selenide light absorbing layer as described above, the preparation method includes the following steps:
  • the atomic ratio (Ga/Ga+In) of gallium to the sum of indium and gallium (Ga/Ga+In) is controlled to be (0.3 ⁇ 0.7):1, a more preferable ratio Yes (0.5 ⁇ 0.7):1.
  • the annealing time of the annealing treatment is 15 minutes to 20 minutes.
  • the first temperature is 340°C-380°C
  • the second temperature is 500°C-600°C.
  • the substrate contains a molybdenum metal layer.
  • selenium vapor is first introduced so that a molybdenum selenide layer is formed on the surface of the molybdenum metal layer, and then Gallium vapor co-evaporates gallium and selenium on the molybdenum selenide layer. Uniformly selenizing the molybdenum metal layer first can make the subsequently prepared copper gallium selenide light absorbing layer better bonded to the molybdenum metal layer.
  • An embodiment of the present invention also provides a solar cell, wherein the solar cell adopts the above-mentioned wide bandgap copper gallium selenide light absorbing layer as the light absorbing layer. Further, the preferred solution of the present invention also provides a tandem solar cell, the top cell of the tandem solar cell adopts a solar cell including the wide bandgap copper gallium selenide light absorbing layer provided by the embodiment of the present invention.
  • the wide-bandgap copper gallium selenide optical absorption layer and its preparation method provided in the above examples are based on the traditional three-step co-evaporation process for preparing copper indium gallium selenide, and replace In with Ga in the first step of co-evaporation.
  • a copper gallium selenide (CGSe) thin film is obtained, which increases the band gap of the light absorbing layer; Indium gallium thin film layer, and then undergo an annealing process, so that the interface between the copper gallium selenide thin film layer and the indium gallium thin film layer has In Cu anti-site defects, and a restructured phase structure that is conducive to charge separation and inhibits interface recombination is formed at the crystal interface , the copper gallium selenide light absorption layer thus obtained can obtain higher efficiency solar cells on the basis of having a wide bandgap, and can be better suitable for tandem solar cells.
  • This embodiment provides a thin-film solar cell, wherein the light-absorbing layer in the thin-film solar cell adopts the wide-bandgap copper-gallium-selenide light-absorbing layer provided in the embodiment of the present invention.
  • the structure of the thin film solar cell is shown in Figure 1, in conjunction with Figure 1, the preparation process of the thin film solar cell comprises the following steps:
  • Step S1 providing a supporting substrate 1 on which a bottom electrode layer 2 is formed.
  • the cleaned soda-lime glass substrate was used as the supporting substrate 1, which was placed in a magnetron sputtering chamber, and a Mo bottom electrode layer 2 with a thickness of 500 nm was deposited by sputtering with a Mo target.
  • Step S2 preparing a CuGaSe light absorbing layer 3 on the bottom electrode layer 2 .
  • the copper-gallium-selenide light-absorbing layer 3 is a wide-bandgap copper-gallium-selenide light-absorbing layer.
  • Absorbent layer comprising the following steps:
  • the first step of co-evaporation deposition which specifically includes: heating the substrate obtained in step S1 to 360°C, raising the temperature of the Ga source to the evaporation temperature of Ga at 965°C, so that Ga changes from a solid state to a gaseous state and becomes Ga vapor, and then Keep warm for 20min. Open the main valve of the Se source 1 minute in advance, let in the Se vapor, open the Se source furnace in advance to allow the Se in the Se furnace to be fully released in the furnace, and manually open the main baffle 30s in advance to allow Se to fall on the Mo metal layer First, a layer of molybdenum selenide is formed to make the Mo layer evenly selenized.
  • the beam source furnace baffle of the Ga source was opened, Ga vapor was introduced, and gallium and selenium were co-evaporated on the Mo metal layer; wherein, as shown in FIG. 2 , the co-evaporation time of gallium and selenium in this embodiment was 36 minutes.
  • the second step of co-evaporation deposition which specifically includes: closing the gallium beam source furnace baffle after the first step of deposition is completed. Raise the temperature of the Cu source to the evaporation temperature of Cu, 1200°C, so that the Cu changes from a solid state to a gaseous state, and then turns into a Cu vapor, and then feeds the Cu vapor into the furnace.
  • the temperature of the substrate was raised from 360°C to 600°C, and then the temperature of the substrate was maintained at 600°C to deposit Cu to form a copper gallium selenide thin film.
  • the deposition of Cu was terminated when the 0.1°C cooling point was observed.
  • the time for co-evaporating copper and selenium in this embodiment is 18 minutes.
  • the third step of co-evaporation deposition after the second step of deposition, close the baffle plate of the copper beam source furnace. Raise the temperature of the In source and the Ga source to the evaporation temperature of In 820°C and the evaporation temperature of Ga 900°C respectively, so that In and Ga change from solid state to gaseous state, into In vapor and into Ga vapor, and keep the temperature of the substrate at 600°C °C, Ga vapor and In vapor are passed into the furnace, and an indium gallium selenide thin film layer is co-evaporated on the copper gallium selenide thin film layer.
  • Ga/Ga+In is 0.5:1 in the third step of co-evaporation deposition, as shown in FIG. 2 , and the co-evaporation time is 14 minutes.
  • the annealing treatment time is 15 minutes.
  • the whole process of preparing the wide bandgap copper gallium selenide light absorbing layer is carried out in the atmosphere of sufficient amount of Se, and the evaporation temperature of Se in the whole process is 650 ⁇ 660°C, and the solid Se become gaseous Se vapor.
  • the wide bandgap copper gallium selenide optical absorption layer prepared above is scanned by electron microscope, and the SEM image of the cross section of the bandgap copper gallium selenide optical absorption layer as shown in Figure 3 is obtained. It can be known from the figure that the copper gallium selenide optical absorption layer obtained in this embodiment
  • the microstructure of the absorbing layer is a large-area uniform polycrystalline film with a grain size of 200nm ⁇ 1 ⁇ m.
  • Step S3 referring to FIG. 1 , preparing and forming a cadmium sulfide buffer layer 4 , a window layer 5 and a top electrode layer 6 on the copper gallium selenide light absorbing layer 3 to obtain the thin film solar cell.
  • the specific preparation process of the cadmium sulfide buffer layer 4, the window layer 5 and the top electrode layer 6 is carried out with reference to the prior art process.
  • the cadmium sulfide buffer layer 4 can be deposited by a chemical water bath;
  • the window layer 5 can be an intrinsic zinc oxide (IZO) layer and an aluminum-doped zinc oxide (AZO) layer prepared by a magnetron sputtering process;
  • the top electrode layer 6 can be It is a metal top electrode layer prepared using a magnetron sputtering process.
  • FIG. 4 is a volt-ampere characteristic curve obtained from the tests.
  • the open circuit voltage (Voc) of the thin film solar cell prepared in the above example is 837mV
  • the short circuit current (Isc) is 19.0mA/cm 2
  • the fill factor (FF) is 66.1%
  • the efficiency (Eff) is 10.5%, and has good electrical properties.
  • the wide bandgap copper gallium selenide light absorbing layer and its preparation method provided in the examples provided in the embodiments of the present invention are based on the traditional three-step co-evaporation process for preparing copper indium gallium selenide, in the first In the first step of co-evaporation, all In is replaced with Ga, so that after the second step of co-evaporation of Cu, a copper gallium selenide (CGSe) film is obtained, which increases the bandgap width of the light absorbing layer;
  • the gallium selenium thin film layer is covered with an In-rich indium gallium thin film layer, and then undergoes an annealing process, so that the interface between the copper gallium selenide thin film layer and the indium gallium thin film layer has In Cu antisite defects, forming a favorable charge at the crystal interface.
  • the restructured phase structure that separates and suppresses interfacial recombination, while ensuring the bandgap width of the copper gallium selenide light absorbing layer, makes the solar cells prepared using the wide bandgap copper gallium selenide light absorbing layer have excellent efficiency, realizing The improved efficiency of wide-bandgap CGSe solar cells can be better suited as the top cell of tandem solar cells.

Abstract

The present invention provides a wide bandgap copper-gallium-selenium light absorption layer and a preparation method therefor. The wide bandgap copper-gallium-selenium light absorption layer comprises a copper-gallium-selenium thin film layer and an indium-gallium thin film layer covering the copper-gallium-selenium thin film layer; and an InCu anti-site defect is formed on the interface of the copper-gallium-selenium thin film layer and the indium-gallium thin film layer by means of an annealing process. The preparation method for a wide bandgap copper-gallium-selenium light absorption layer comprises: heating a substrate to a first temperature, and co-evaporating gallium and selenium on the substrate; increasing the temperature of the substrate to a second temperature, and co-evaporating copper and selenium on the substrate; keeping the temperature of the substrate at the second temperature, and co-evaporating indium, gallium, and selenium on the substrate; and keeping the temperature of the substrate at the second temperature, and performing annealing on the substrate in a selenium atmosphere to prepare the wide bandgap copper-gallium-selenium light absorption layer. The present invention further provides a solar cell comprising the wide bandgap copper-gallium-selenium light absorption layer. According to the wide bandgap copper-gallium-selenium light absorption layer provided by the present invention, a solar cell having higher efficiency can be obtained on the basis of having a wide bandgap, and the solar cell can be better suitable for a laminated solar cell.

Description

宽禁带铜镓硒光吸收层及其制备方法、太阳能电池Wide bandgap copper gallium selenide photoabsorbing layer and its preparation method, solar cell 技术领域technical field
本发明属于太阳能电池技术领域，具体涉及一种宽禁带铜镓硒光吸收层及其制备方法，还涉及包含所述宽禁带铜镓硒光吸收层的太阳能电池。The invention belongs to the technical field of solar cells, and in particular relates to a wide-bandgap copper-gallium-selenium light-absorbing layer and a preparation method thereof, and also relates to a solar cell comprising the wide-bandgap copper-gallium-selenium light-absorbing layer.
背景技术Background technique
近年来，随着光伏技术的迅速发展，多种单结太阳能电池效率已经逐步趋进该体系效率的理论极限。通过技术进步继续提升单结电池的效率将变得异常艰难。叠层太阳能电池可以将匹配不同光谱波段的吸收层串联，以增加电池对太阳光光谱的吸收宽度。同时，叠层太阳能电池不同禁带宽度的吸收层吸收不同能量的光子，可以降低高能光子超出禁带宽度的多余能量造成的热弛豫损失，最大限度地将光能变成电能，从而大幅提高光电转换效率。In recent years, with the rapid development of photovoltaic technology, the efficiency of various single-junction solar cells has gradually approached the theoretical limit of the efficiency of the system. It will become extremely difficult to continue to improve the efficiency of single-junction cells through technological progress. Tandem solar cells can connect absorbing layers matching different spectral bands in series to increase the absorption width of the solar spectrum. At the same time, the absorption layers of different bandgap widths of tandem solar cells absorb photons of different energies, which can reduce the thermal relaxation loss caused by the excess energy of high-energy photons beyond the bandgap width, and maximize the conversion of light energy into electrical energy, thereby greatly improving Photoelectric conversion efficiency.
叠层电池中主流的双结叠层电池需要一个窄禁带的底电池和一个宽禁带的顶电池。然而用于宽禁带的顶电池材料却十分缺稀。为了与窄禁带宽度的底电池吸收层材料相匹配，比如1.1eV禁带宽度的p型晶硅，或1.0eV禁带宽度的p型铜铟硒，顶电池材料要求是禁带宽度在1.6eV-1.7eV之间的p型材料，在较长的一段时间内，价格昂贵的III-V族材料是唯一的选择。寻找高效率、低成本的p型宽禁带顶电池材料是双结叠层电池未来发展的关键。The mainstream double-junction tandem cell in tandem cells requires a bottom cell with a narrow bandgap and a top cell with a wide bandgap. However, top cell materials for wide bandgap are scarce. In order to match the absorption layer material of the bottom cell with a narrow bandgap, such as p-type silicon with a bandgap of 1.1eV, or p-type copper indium selenide with a bandgap of 1.0eV, the top cell material is required to have a bandgap of 1.6 For p-type materials between eV-1.7eV, expensive III-V materials are the only choice for a long period of time. Finding high-efficiency, low-cost p-type wide-bandgap top cell materials is the key to the future development of double-junction stacked cells.
CIGS（铜铟镓硒）的禁带宽度可以在1.0-2.5 eV区间灵活调控。目前效率最高的CIGS太阳能电池，禁带宽度为1.15eV，对应的Ga/Ga+In 比例为0.3。为获得更高的禁带宽度，目前国际上主流的研究方向是通过阳离子、阴离子替换得以实现。在阳离子替换方面主要是增加Ga组分含量来提高CIGS材料的吸收带隙。CuInGaSe 2中的In如果全部被Ga替换而形成铜镓硒(CGSe)，CGSe的禁带宽度可以达到1.7eV。然而多个研究单位实验发现太阳能电池的效率随Ga含量的增加而降低。 The band gap of CIGS (copper indium gallium selenide) can be flexibly adjusted in the range of 1.0-2.5 eV. Currently the most efficient CIGS solar cell has a band gap of 1.15eV and a corresponding Ga/Ga+In ratio of 0.3. In order to obtain a higher band gap, the current mainstream research direction in the world is to replace cations and anions. In terms of cation replacement, it is mainly to increase the Ga component content to increase the absorption band gap of CIGS materials. If all In in CuInGaSe 2 is replaced by Ga to form copper gallium selenide (CGSe), the forbidden band width of CGSe can reach 1.7eV. However, many research units have found that the efficiency of solar cells decreases with the increase of Ga content.
传统的CIGS材料的表面和晶界面存在有序缺陷再构层(ODC层)，该结构具有固定的晶格结构和能带结构，可以大大降低载流子在晶界面的复合几率。这种有序缺陷再构层中存在大量In Cu反位缺陷，然而为了获得高禁带宽度的铜镓硒，CuInGaSe 2中的In全部被Ga替换，如上所述的有序缺陷再构层难以在界面处形成，无法抑制表面和晶界面的电子空穴复合，降低了电池效率。 There is an ordered defect reconstruction layer (ODC layer) on the surface and crystal interface of traditional CIGS materials. This structure has a fixed lattice structure and energy band structure, which can greatly reduce the recombination probability of carriers at the crystal interface. There are a large number of In and Cu antisite defects in this ordered defect reconstruction layer. However, in order to obtain copper gallium selenide with a high band gap, all In in CuInGaSe 2 is replaced by Ga. The above-mentioned ordered defect reconstruction layer is difficult Formed at the interface, it cannot inhibit the electron-hole recombination at the surface and crystal interface, which reduces the battery efficiency.
技术问题technical problem
鉴于现有技术存在的不足，本发明提供一种宽禁带铜镓硒光吸收层及其制备方法、太阳能电池，以解决现有技术中为了获得高禁带宽度的铜镓硒而导致电池效率降低的问题。In view of the deficiencies in the prior art, the present invention provides a wide-bandgap copper-gallium-selenide light-absorbing layer and its preparation method, and a solar cell to solve the problem of battery efficiency in the prior art in order to obtain copper-gallium-selenide with a high bandgap width. Lowering the problem.
技术解决方案technical solution
为实现上述发明目的，本发明采用了如下的技术方案：In order to realize the above-mentioned purpose of the invention, the present invention has adopted following technical scheme:
一种宽禁带铜镓硒光吸收层，包括铜镓硒薄膜层和覆设于所述铜镓硒薄膜层上的铟镓薄膜层，所述铜镓硒薄膜层和所述铟镓薄膜层的界面经由退火工艺形成有In Cu反位缺陷。 A wide bandgap copper gallium selenide light absorbing layer, comprising a copper gallium selenide thin film layer and an indium gallium thin film layer covered on the copper gallium selenide thin film layer, the copper gallium selenide thin film layer and the indium gallium selenide thin film layer The interface with InCu antisite defects was formed through an annealing process.
优选地，所述铟镓薄膜层中镓与铟和镓总和的原子比为（0.3~0.7）：1。Preferably, the atomic ratio of gallium to the sum of indium and gallium in the indium gallium thin film layer is (0.3-0.7):1.
优选地，所述铟镓薄膜层中镓与铟和镓总和的原子比为（0.5~0.7）：1。Preferably, the atomic ratio of gallium to the sum of indium and gallium in the indium gallium thin film layer is (0.5-0.7):1.
优选地，所述宽禁带铜镓硒光吸收层的厚度为1.0μm ~3.0μm。Preferably, the thickness of the wide bandgap copper gallium selenide light absorbing layer is 1.0 μm to 3.0 μm.
本发明还提供了一种如上所述的宽禁带铜镓硒光吸收层的制备方法，包括以下步骤：The present invention also provides a method for preparing the wide-bandgap copper-gallium-selenium light-absorbing layer as described above, comprising the following steps:
S10、将基底加热至第一温度，在所述基底上共蒸镓和硒；S10, heating the substrate to a first temperature, and co-evaporating gallium and selenium on the substrate;
S20、提高所述基底的温度至第二温度，在所述基底上共蒸铜和硒；S20, increasing the temperature of the substrate to a second temperature, and co-evaporating copper and selenium on the substrate;
S30、保持所述基底的温度为第二温度，在所述基底上共蒸铟、镓和硒；S30, keeping the temperature of the substrate at a second temperature, and co-evaporating indium, gallium and selenium on the substrate;
S40、保持所述基底的温度为第二温度，在硒气氛下对所述基底进行退火处理，在所述基底上制备获得所述宽禁带铜镓硒光吸收层；S40. Keeping the temperature of the substrate at the second temperature, performing annealing treatment on the substrate in a selenium atmosphere, and preparing the wide bandgap copper gallium selenide light absorbing layer on the substrate;
其中，所述步骤S30中，在共蒸铟、镓和硒时，控制镓与铟和镓总和的原子比为（0.3~0.7）：1。Wherein, in the step S30, when co-evaporating indium, gallium and selenium, the atomic ratio of gallium to the sum of indium and gallium is controlled to be (0.3-0.7):1.
优选地，所述步骤S30中，在共蒸铟、镓和硒时，控制镓与铟和镓总和的原子比为（0.5~0.7）：1。Preferably, in the step S30, when co-evaporating indium, gallium and selenium, the atomic ratio of gallium to the sum of indium and gallium is controlled to be (0.5-0.7):1.
优选地，所述退火处理的退火时间为15min~20min。Preferably, the annealing time of the annealing treatment is 15 minutes to 20 minutes.
优选地，所述第一温度为340℃~380℃，所述第二温度为500℃~600℃。Preferably, the first temperature is 340°C-380°C, and the second temperature is 500°C-600°C.
优选地，所述基底上包含有钼金属层，所述步骤S10共蒸镓和硒时，首先通入硒蒸气使得所述钼金属层的表面形成硒化钼层，然后再通入镓蒸气在所述硒化钼层上共蒸镓和硒。Preferably, the substrate contains a molybdenum metal layer. When gallium and selenium are co-evaporated in the step S10, selenium vapor is first introduced to form a molybdenum selenide layer on the surface of the molybdenum metal layer, and then gallium vapor is introduced to form a molybdenum selenide layer. Gallium and selenium are co-evaporated on the molybdenum selenide layer.
本发明实施例还提供了一种太阳能电池，所述太阳能电池包括如上所述的宽禁带铜镓硒光吸收层。An embodiment of the present invention also provides a solar cell, which includes the above-mentioned wide bandgap copper gallium selenide light absorbing layer.
本发明实施例提供的宽禁带铜镓硒光吸收层及其制备方法，基于传统的三步共蒸制备铜铟镓硒的工艺的基础上，在第一步共蒸时用Ga全部替换In，由此在第二步共蒸Cu之后获得铜镓硒(CGSe)薄膜，增加了光吸收层的禁带宽度；第三步共蒸再引入In，在铜镓硒薄膜层上覆设富In的铟镓薄膜层，然后再经过退火工艺，使得铜镓硒薄膜层和铟镓薄膜层的界面形成有In Cu反位缺陷，在晶界面形成了有利于电荷分离、抑制界面复合的再构相结构，由此获得的铜镓硒光吸收层在具备宽禁带的基础上又能获得更高效率太阳能电池，可以更好地适用于叠层太阳能电池。 The wide bandgap copper gallium selenium light absorbing layer and its preparation method provided by the embodiments of the present invention are based on the traditional three-step co-evaporation process for preparing copper indium gallium selenide, and replace In with Ga in the first step of co-evaporation. , thus obtaining copper gallium selenide (CGSe) thin film after co-evaporation of Cu in the second step, which increases the bandgap width of the light absorbing layer; the third step of co-evaporation re-introduces In, and covers the copper gallium selenide film layer with rich In Indium Gallium thin film layer, and then through the annealing process, the interface between the CuGaSe thin film layer and the InGa thin film layer has In Cu antisite defects, and a restructured phase that is conducive to charge separation and inhibits interface recombination is formed at the crystal interface. structure, the copper-gallium-selenide light-absorbing layer thus obtained can obtain higher-efficiency solar cells on the basis of having a wide bandgap, and can be better suitable for tandem solar cells.
附图说明Description of drawings
图1是本发明实施例中制备的薄膜太阳能电池的结构示意图；Fig. 1 is the structural representation of the thin-film solar cell prepared in the embodiment of the present invention;
图2是本发明实施例中的宽禁带铜镓硒光吸收层的制备方法的流程图；Fig. 2 is the flowchart of the preparation method of the wide bandgap copper gallium selenide light absorbing layer in the embodiment of the present invention;
图3是本发明实施例中制备的禁带铜镓硒光吸收层的SEM截面图；Fig. 3 is the SEM sectional view of the bandgap copper gallium selenide photoabsorbing layer prepared in the embodiment of the present invention;
图4是本发明实施例中制备的薄膜太阳能电池的伏安曲线图。Fig. 4 is a graph of voltammetry of the thin film solar cell prepared in the embodiment of the present invention.
本发明的实施方式Embodiments of the present invention
为使本发明的目的、技术方案和优点更加清楚，下面结合附图对本发明的具体实施方式进行详细说明。这些优选实施方式的示例在附图中进行了例示。附图中所示和根据附图描述的本发明的实施方式仅仅是示例性的，并且本发明并不限于这些实施方式。In order to make the object, technical solution and advantages of the present invention clearer, the specific implementation manners of the present invention will be described in detail below in conjunction with the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the invention shown in and described with reference to the drawings are merely exemplary, and the invention is not limited to these embodiments.
在此，还需要说明的是，为了避免因不必要的细节而模糊了本发明，在附图中仅仅示出了与根据本发明的方案密切相关的结构和/或处理步骤，而省略了与本发明关系不大的其他细节。Here, it should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only the structures and/or processing steps that are closely related to the solution according to the present invention are shown in the drawings, while those related to the present invention are omitted. Other details are not relevant to the invention.
本发明实施例首先提供了一种宽禁带铜镓硒光吸收层，包括铜镓硒薄膜层和覆设于所述铜镓硒薄膜层上的铟镓薄膜层，所述铜镓硒薄膜层和所述铟镓薄膜层的界面经由退火工艺形成有In Cu反位缺陷，在晶界面形成了有利于电荷分离、抑制界面复合的再构相结构。 The embodiment of the present invention firstly provides a wide bandgap copper gallium selenide light absorbing layer, comprising a copper gallium selenide thin film layer and an indium gallium thin film layer covered on the copper gallium selenide thin film layer, the copper gallium selenide thin film layer In the interface with the indium gallium thin film layer, an In Cu antisite defect is formed through an annealing process, and a restructured phase structure that is beneficial to charge separation and inhibits interface recombination is formed at the crystal interface.
在优先的方案中，所述铟镓薄膜层中镓与铟和镓总和的原子比（Ga/Ga+In）为（0.3~0.7）：1，更为优选的比例是（0.5~0.7）：1。In the preferred solution, the atomic ratio of gallium to the sum of indium and gallium (Ga/Ga+In) in the indium gallium thin film layer is (0.3~0.7):1, and a more preferable ratio is (0.5~0.7): 1.
在优先的方案中，所述宽禁带铜镓硒光吸收层的厚度为1.0μm ~3.0μm。In a preferred scheme, the thickness of the wide bandgap copper gallium selenide light absorbing layer is 1.0 μm to 3.0 μm.
本发明实施例还提供了一种如上述所述的宽禁带铜镓硒光吸收层的制备方法，所述制备方法包括以下步骤：The embodiment of the present invention also provides a method for preparing the wide bandgap copper gallium selenide light absorbing layer as described above, the preparation method includes the following steps:
S10、将基底加热至第一温度，在所述基底上共蒸镓和硒。S10, heating the substrate to a first temperature, and co-evaporating gallium and selenium on the substrate.
S20、提高所述基底的温度至第二温度，在所述基底上共蒸铜和硒。S20, increasing the temperature of the substrate to a second temperature, and co-evaporating copper and selenium on the substrate.
S30、保持所述基底的温度为第二温度，在所述基底上共蒸铟、镓和硒。S30. Keep the temperature of the substrate at the second temperature, and co-evaporate indium, gallium and selenium on the substrate.
S40、保持所述基底的温度为第二温度，在硒气氛下对所述基底进行退火处理，在所述基底上制备获得所述宽禁带铜镓硒光吸收层。S40. Keeping the temperature of the substrate at the second temperature, performing annealing treatment on the substrate in a selenium atmosphere, and preparing the wide bandgap copper gallium selenide light absorbing layer on the substrate.
具体地，所述步骤S30中，在共蒸铟、镓和硒时，控制镓与铟和镓总和的原子比（Ga/Ga+In）为（0.3~0.7）：1，更为优选的比例是（0.5~0.7）：1。Specifically, in the step S30, when indium, gallium and selenium are co-evaporated, the atomic ratio (Ga/Ga+In) of gallium to the sum of indium and gallium (Ga/Ga+In) is controlled to be (0.3~0.7):1, a more preferable ratio Yes (0.5~0.7):1.
在优先的方案中，所述退火处理的退火时间为15min~20min。In a preferred scheme, the annealing time of the annealing treatment is 15 minutes to 20 minutes.
在具体的方案中，所述第一温度为340℃~380℃，所述第二温度为500℃~600℃。In a specific scheme, the first temperature is 340°C-380°C, and the second temperature is 500°C-600°C.
在优先的方案中，所述基底上包含有钼金属层，所述步骤S10共蒸镓和硒时，首先通入硒蒸气使得所述钼金属层的表面形成硒化钼层，然后再通入镓蒸气在所述硒化钼层上共蒸镓和硒。先将钼金属层均匀硒化，可以使得后续制备的铜镓硒光吸收层更好地结合到钼金属层上。In a preferred solution, the substrate contains a molybdenum metal layer. When gallium and selenium are co-evaporated in step S10, selenium vapor is first introduced so that a molybdenum selenide layer is formed on the surface of the molybdenum metal layer, and then Gallium vapor co-evaporates gallium and selenium on the molybdenum selenide layer. Uniformly selenizing the molybdenum metal layer first can make the subsequently prepared copper gallium selenide light absorbing layer better bonded to the molybdenum metal layer.
本发明实施例还提供了一种太阳能电池，其中，所述太阳能电池采用如上所述的宽禁带铜镓硒光吸收层作为光吸收层。进一步地，本发明优选的方案中还提供一种叠层太阳能电池，所述叠层太阳能电池顶电池采用了包含有本发明实施例提供的宽禁带铜镓硒光吸收层的太阳能电池。An embodiment of the present invention also provides a solar cell, wherein the solar cell adopts the above-mentioned wide bandgap copper gallium selenide light absorbing layer as the light absorbing layer. Further, the preferred solution of the present invention also provides a tandem solar cell, the top cell of the tandem solar cell adopts a solar cell including the wide bandgap copper gallium selenide light absorbing layer provided by the embodiment of the present invention.
以上实施例提供的宽禁带铜镓硒光吸收层及其制备方法，基于传统的三步共蒸制备铜铟镓硒的工艺的基础上，在第一步共蒸时用Ga全部替换In，由此在第二步共蒸Cu之后获得铜镓硒(CGSe)薄膜，增加了光吸收层的禁带宽度；第三步共蒸再引入In，在铜镓硒薄膜层上覆设富In的铟镓薄膜层，然后再经过退火工艺，使得铜镓硒薄膜层和铟镓薄膜层的界面形成有In Cu反位缺陷，在晶界面形成了有利于电荷分离、抑制界面复合的再构相结构，由此获得的铜镓硒光吸收层在具备宽禁带的基础上又能获得更高效率太阳能电池，可以更好地适用于叠层太阳能电池。 The wide-bandgap copper gallium selenide optical absorption layer and its preparation method provided in the above examples are based on the traditional three-step co-evaporation process for preparing copper indium gallium selenide, and replace In with Ga in the first step of co-evaporation. Therefore, after the second co-evaporation of Cu, a copper gallium selenide (CGSe) thin film is obtained, which increases the band gap of the light absorbing layer; Indium gallium thin film layer, and then undergo an annealing process, so that the interface between the copper gallium selenide thin film layer and the indium gallium thin film layer has In Cu anti-site defects, and a restructured phase structure that is conducive to charge separation and inhibits interface recombination is formed at the crystal interface , the copper gallium selenide light absorption layer thus obtained can obtain higher efficiency solar cells on the basis of having a wide bandgap, and can be better suitable for tandem solar cells.
实施例1Example 1
本实施例提供了一种薄膜太阳能电池，其中，所述薄膜太阳能电池中的光吸收层采用本发明实施例提供的宽禁带铜镓硒光吸收层。所述薄膜太阳能电池的结构如图1所示，结合图1，所述薄膜太阳能电池的制备工艺包括以下步骤：This embodiment provides a thin-film solar cell, wherein the light-absorbing layer in the thin-film solar cell adopts the wide-bandgap copper-gallium-selenide light-absorbing layer provided in the embodiment of the present invention. The structure of the thin film solar cell is shown in Figure 1, in conjunction with Figure 1, the preparation process of the thin film solar cell comprises the following steps:
步骤S1、提供支撑衬底1，在所述支撑衬底1上制备形成底电极层2。Step S1 , providing a supporting substrate 1 on which a bottom electrode layer 2 is formed.
具体地，将洗干净的钠钙玻璃基底为支撑衬底1，放入磁控溅射腔室中，用 Mo靶材，溅射沉积一层厚度为500nm的Mo底电极层2。Specifically, the cleaned soda-lime glass substrate was used as the supporting substrate 1, which was placed in a magnetron sputtering chamber, and a Mo bottom electrode layer 2 with a thickness of 500 nm was deposited by sputtering with a Mo target.
步骤S2、在所述底电极层2上制备铜镓硒光吸收层3。Step S2 , preparing a CuGaSe light absorbing layer 3 on the bottom electrode layer 2 .
具体地，所述铜镓硒光吸收层3为宽禁带铜镓硒光吸收层，结合图2所示，本实施例中，采用三步共蒸发法制备所述宽禁带铜镓硒薄膜吸收层，包括以下步骤：Specifically, the copper-gallium-selenide light-absorbing layer 3 is a wide-bandgap copper-gallium-selenide light-absorbing layer. As shown in FIG. Absorbent layer, comprising the following steps:
S10、将基底加热至第一温度，在所述基底上共蒸镓和硒。S10, heating the substrate to a first temperature, and co-evaporating gallium and selenium on the substrate.
即第一步共蒸沉积，具体包括：将步骤S1获得的基底加热至360℃，将Ga源的温度升到Ga的蒸发温度965℃，使得Ga由固态变为气态，变成Ga蒸气，随后保温20min。提前1min打开Se源的主阀，通入Se蒸气，提前打开Se源炉是让Se炉内的Se充分释放在炉内，提前30s手动打开主挡板，是为了让Se落在Mo金属层上先生成一层硒化钼，以使得Mo层均匀硒化。之后打开Ga源的束源炉挡板，通入Ga蒸气，在Mo金属层上共蒸镓和硒；其中，如图2所示，本实施例中共蒸镓和硒的时间为36min。That is, the first step of co-evaporation deposition, which specifically includes: heating the substrate obtained in step S1 to 360°C, raising the temperature of the Ga source to the evaporation temperature of Ga at 965°C, so that Ga changes from a solid state to a gaseous state and becomes Ga vapor, and then Keep warm for 20min. Open the main valve of the Se source 1 minute in advance, let in the Se vapor, open the Se source furnace in advance to allow the Se in the Se furnace to be fully released in the furnace, and manually open the main baffle 30s in advance to allow Se to fall on the Mo metal layer First, a layer of molybdenum selenide is formed to make the Mo layer evenly selenized. Afterwards, the beam source furnace baffle of the Ga source was opened, Ga vapor was introduced, and gallium and selenium were co-evaporated on the Mo metal layer; wherein, as shown in FIG. 2 , the co-evaporation time of gallium and selenium in this embodiment was 36 minutes.
S20、提高所述基底的温度至第二温度，在所述基底上共蒸铜和硒。S20, increasing the temperature of the substrate to a second temperature, and co-evaporating copper and selenium on the substrate.
即第二步共蒸沉积，具体包括：第一步沉积结束后关闭镓的束源炉挡板。将Cu源的温度升到Cu的蒸发温度1200℃，使得Cu由固态变为气态，变成Cu蒸气，向炉内通入Cu蒸气。将基底的温度由 360℃升温到 600℃，之后将基底的温度维持在600℃下沉积Cu，制备形成铜镓硒薄膜。在沉积Cu的过程中，观察到0.1℃降温点的出现时，结束Cu的沉积。即，当Cu与Ga的化学计量比达 1:1 时，继续蒸发铜，硒和铜会生成硒化铜，液相的硒化铜会吸热发生短暂的降温现象，大约维持6 s ~10s，当观察到短暂的降温现象出现时，说明铜的生长完成，此时降低铜源温度，关闭铜源，结束Cu的沉积。其中，如图2所示，本实施例中共蒸铜和硒的时间为18min。That is, the second step of co-evaporation deposition, which specifically includes: closing the gallium beam source furnace baffle after the first step of deposition is completed. Raise the temperature of the Cu source to the evaporation temperature of Cu, 1200°C, so that the Cu changes from a solid state to a gaseous state, and then turns into a Cu vapor, and then feeds the Cu vapor into the furnace. The temperature of the substrate was raised from 360°C to 600°C, and then the temperature of the substrate was maintained at 600°C to deposit Cu to form a copper gallium selenide thin film. During the process of depositing Cu, the deposition of Cu was terminated when the 0.1°C cooling point was observed. That is, when the stoichiometric ratio of Cu and Ga reaches 1:1, continue to evaporate copper, selenium and copper will generate copper selenide, and the copper selenide in the liquid phase will absorb heat and cause a short-term cooling phenomenon, which lasts for about 6 s to 10 s , when a short-term cooling phenomenon is observed, it indicates that the growth of copper is completed. At this time, the temperature of the copper source is lowered, the copper source is turned off, and the deposition of Cu is ended. Wherein, as shown in FIG. 2, the time for co-evaporating copper and selenium in this embodiment is 18 minutes.
S30、保持所述基底的温度为第二温度，在所述基底上共蒸铟、镓和硒。S30. Keep the temperature of the substrate at the second temperature, and co-evaporate indium, gallium and selenium on the substrate.
第三步共蒸沉积：第二步沉积结束后关闭铜的束源炉挡板。将In源和Ga源的温度分别升到In的蒸发温度820℃和Ga的蒸发温度900℃，使得In和Ga由固态变为气态，变成In蒸气和变成Ga蒸气，保持基底的温度600℃，向炉内通入Ga蒸气和In蒸气，在铜镓硒薄膜层上共蒸铟镓硒薄膜层。本实施例中，第三步共蒸沉积时Ga/Ga+In为0.5:1，如图2所示，共蒸时间为14min。The third step of co-evaporation deposition: after the second step of deposition, close the baffle plate of the copper beam source furnace. Raise the temperature of the In source and the Ga source to the evaporation temperature of In 820°C and the evaporation temperature of Ga 900°C respectively, so that In and Ga change from solid state to gaseous state, into In vapor and into Ga vapor, and keep the temperature of the substrate at 600°C ℃, Ga vapor and In vapor are passed into the furnace, and an indium gallium selenide thin film layer is co-evaporated on the copper gallium selenide thin film layer. In this embodiment, Ga/Ga+In is 0.5:1 in the third step of co-evaporation deposition, as shown in FIG. 2 , and the co-evaporation time is 14 minutes.
S40、保持所述基底的温度为第二温度，在硒气氛下对所述基底进行退火处理，在所述基底上制备获得所述宽禁带铜镓硒光吸收层。S40. Keeping the temperature of the substrate at the second temperature, performing annealing treatment on the substrate in a selenium atmosphere, and preparing the wide bandgap copper gallium selenide light absorbing layer on the substrate.
具体地，保持基底的温度600℃，在Se气氛下对基底进行退火处理，之后关闭各源开始降温，当基底的温度降低为300℃时，关闭Se源主挡板，当基底的温度降为 200℃以下时，可取出制备形成的宽禁带铜镓硒光吸收层。其中，如图2所示，退火处理的时间为15min。Specifically, keep the temperature of the substrate at 600°C, anneal the substrate in a Se atmosphere, and then turn off the sources to start cooling. When the temperature of the substrate drops to 300°C, turn off the main baffle plate of the Se source. When the temperature of the substrate drops to When the temperature is below 200°C, the prepared wide-bandgap copper gallium selenide light absorbing layer can be taken out. Wherein, as shown in FIG. 2 , the annealing treatment time is 15 minutes.
其中，以上制备宽禁带铜镓硒光吸收层的整个过程都是在足量的Se 的气氛中进行的，整个过程中Se 的蒸发温度为 650~660℃，该温度下可将固体的Se变为气态的Se蒸气。Among them, the whole process of preparing the wide bandgap copper gallium selenide light absorbing layer is carried out in the atmosphere of sufficient amount of Se, and the evaporation temperature of Se in the whole process is 650~660°C, and the solid Se Become gaseous Se vapor.
对以上制备形成的宽禁带铜镓硒光吸收层进行电镜扫描，得到如图3所示的禁带铜镓硒光吸收层截面的SEM图，由图可知本实施例得到的铜镓硒光吸收层的微观结构为大面积均匀多晶薄膜，晶粒大小为200nm~1μm。The wide bandgap copper gallium selenide optical absorption layer prepared above is scanned by electron microscope, and the SEM image of the cross section of the bandgap copper gallium selenide optical absorption layer as shown in Figure 3 is obtained. It can be known from the figure that the copper gallium selenide optical absorption layer obtained in this embodiment The microstructure of the absorbing layer is a large-area uniform polycrystalline film with a grain size of 200nm~1μm.
步骤S3、参阅图1，在所述铜镓硒光吸收层3上由此制备形成硫化镉缓冲层4、窗口层5和顶电极层6，获得所述薄膜太阳能电池。Step S3 , referring to FIG. 1 , preparing and forming a cadmium sulfide buffer layer 4 , a window layer 5 and a top electrode layer 6 on the copper gallium selenide light absorbing layer 3 to obtain the thin film solar cell.
其中，硫化镉缓冲层4、窗口层5和顶电极层6的具体制备工艺参照已有技术工艺进行。例如硫化镉缓冲层4可以使用化学水浴沉积法；窗口层5可以是使用磁控溅射工艺制备的本征氧化锌（IZO）层和铝掺杂氧化锌（AZO）层；顶电极层6可以是使用磁控溅射工艺制备的金属顶电极层。Wherein, the specific preparation process of the cadmium sulfide buffer layer 4, the window layer 5 and the top electrode layer 6 is carried out with reference to the prior art process. For example, the cadmium sulfide buffer layer 4 can be deposited by a chemical water bath; the window layer 5 can be an intrinsic zinc oxide (IZO) layer and an aluminum-doped zinc oxide (AZO) layer prepared by a magnetron sputtering process; the top electrode layer 6 can be It is a metal top electrode layer prepared using a magnetron sputtering process.
本实施例中对以上实施例制备获得的薄膜太阳能电池进行电性测试，图4是测试获得的伏安特性曲线。根据如图4所示的伏安特性曲线，可以计算出以上实施例制备获得的薄膜太阳能电池开路电压（Voc）为837mV，短路电流（Isc）为19.0mA/cm 2，填充因子（FF）为66.1%，效率（Eff）为10.5%，具有良好的电性能。 In this embodiment, electrical tests are performed on the thin-film solar cells prepared in the above embodiments, and FIG. 4 is a volt-ampere characteristic curve obtained from the tests. According to the volt-ampere characteristic curve shown in Figure 4, it can be calculated that the open circuit voltage (Voc) of the thin film solar cell prepared in the above example is 837mV, the short circuit current (Isc) is 19.0mA/cm 2 , and the fill factor (FF) is 66.1%, the efficiency (Eff) is 10.5%, and has good electrical properties.
综上所述，本发明实施例提供的实施例提供的宽禁带铜镓硒光吸收层及其制备方法，基于传统的三步共蒸制备铜铟镓硒的工艺的基础上，在第一步共蒸时用Ga全部替换In，由此在第二步共蒸Cu之后获得铜镓硒(CGSe)薄膜，增加了光吸收层的禁带宽度；第三步共蒸再引入In，在铜镓硒薄膜层上覆设富In的铟镓薄膜层，然后再经过退火工艺，使得铜镓硒薄膜层和铟镓薄膜层的界面形成有In Cu反位缺陷，在晶界面形成了有利于电荷分离、抑制界面复合的再构相结构，在保证了铜镓硒光吸收层的禁带宽度的同时，使得使用该宽禁带铜镓硒光吸收层制备的太阳能电池具备优良的效率，实现了宽禁带CGSe太阳能电池效率的提高，可以更好地适用于作为叠层太阳能电池的顶电池。 In summary, the wide bandgap copper gallium selenide light absorbing layer and its preparation method provided in the examples provided in the embodiments of the present invention are based on the traditional three-step co-evaporation process for preparing copper indium gallium selenide, in the first In the first step of co-evaporation, all In is replaced with Ga, so that after the second step of co-evaporation of Cu, a copper gallium selenide (CGSe) film is obtained, which increases the bandgap width of the light absorbing layer; The gallium selenium thin film layer is covered with an In-rich indium gallium thin film layer, and then undergoes an annealing process, so that the interface between the copper gallium selenide thin film layer and the indium gallium thin film layer has In Cu antisite defects, forming a favorable charge at the crystal interface. The restructured phase structure that separates and suppresses interfacial recombination, while ensuring the bandgap width of the copper gallium selenide light absorbing layer, makes the solar cells prepared using the wide bandgap copper gallium selenide light absorbing layer have excellent efficiency, realizing The improved efficiency of wide-bandgap CGSe solar cells can be better suited as the top cell of tandem solar cells.
以上所述仅是本申请的具体实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本申请原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也应视为本申请的保护范围。The above description is only the specific implementation of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present application, some improvements and modifications can also be made. It should be regarded as the protection scope of this application.

Claims (10)

  1. 一种宽禁带铜镓硒光吸收层，其特征在于，包括铜镓硒薄膜层和覆设于所述铜镓硒薄膜层上的铟镓薄膜层，所述铜镓硒薄膜层和所述铟镓薄膜层的界面经由退火工艺形成有In Cu反位缺陷。 A wide bandgap copper gallium selenide light absorption layer, characterized in that it includes a copper gallium selenide thin film layer and an indium gallium thin film layer covered on the copper gallium selenide thin film layer, the copper gallium selenide thin film layer and the The interface of the indium gallium thin film layer is formed with In Cu antisite defects through an annealing process.
  2. 根据权利要求1所述的宽禁带铜镓硒光吸收层，其特征在于，所述铟镓薄膜层中镓与铟和镓总和的原子比为（0.3~0.7）：1。The wide bandgap copper gallium selenide light absorbing layer according to claim 1, characterized in that the atomic ratio of gallium to the sum of indium and gallium in the indium gallium thin film layer is (0.3-0.7):1.
  3. 根据权利要求2所述的宽禁带铜镓硒光吸收层，其特征在于，所述铟镓薄膜层中镓与铟和镓总和的原子比为（0.5~0.7）：1。The wide bandgap copper gallium selenide light absorbing layer according to claim 2, characterized in that the atomic ratio of gallium to the sum of indium and gallium in the indium gallium thin film layer is (0.5-0.7):1.
  4. 根据权利要求1-3任一所述的宽禁带铜镓硒光吸收层，其特征在于，所述宽禁带铜镓硒光吸收层的厚度为1.0μm ~3.0μm。The wide-bandgap copper-gallium-selenide light-absorbing layer according to any one of claims 1-3, wherein the thickness of the wide-bandgap copper-gallium-selenide light-absorbing layer is 1.0 μm to 3.0 μm.
  5. 一种如权利要求1-4任一所述的宽禁带铜镓硒光吸收层的制备方法，其特征在于，包括以下步骤：A preparation method of the wide bandgap copper gallium selenide light absorbing layer as described in any one of claims 1-4, characterized in that it comprises the following steps:
    S10、将基底加热至第一温度，在所述基底上共蒸镓和硒；S10, heating the substrate to a first temperature, and co-evaporating gallium and selenium on the substrate;
    S20、提高所述基底的温度至第二温度，在所述基底上共蒸铜和硒；S20, increasing the temperature of the substrate to a second temperature, and co-evaporating copper and selenium on the substrate;
    S30、保持所述基底的温度为第二温度，在所述基底上共蒸铟、镓和硒；S30, keeping the temperature of the substrate at a second temperature, and co-evaporating indium, gallium and selenium on the substrate;
    S40、保持所述基底的温度为第二温度，在硒气氛下对所述基底进行退火处理，在所述基底上制备获得所述宽禁带铜镓硒光吸收层；S40. Keeping the temperature of the substrate at the second temperature, performing annealing treatment on the substrate in a selenium atmosphere, and preparing the wide bandgap copper gallium selenide light absorbing layer on the substrate;
    其中，所述步骤S30中，在共蒸铟、镓和硒时，控制镓与铟和镓总和的原子比为（0.3~0.7）：1。Wherein, in the step S30, when co-evaporating indium, gallium and selenium, the atomic ratio of gallium to the sum of indium and gallium is controlled to be (0.3-0.7):1.
  6. 根据权利要求5所述的制备方法，其特征在于，所述步骤S30中，在共蒸铟、镓和硒时，控制镓与铟和镓总和的原子比为（0.5~0.7）：1。The preparation method according to claim 5, characterized in that, in the step S30, when indium, gallium and selenium are co-evaporated, the atomic ratio of gallium to the sum of indium and gallium is controlled to be (0.5-0.7):1.
  7. 根据权利要求5所述的制备方法，其特征在于，所述退火处理的退火时间为15min~20min。The preparation method according to claim 5, characterized in that, the annealing time of the annealing treatment is 15min-20min.
  8. 根据权利要求5-7任一所述的制备方法，其特征在于，所述第一温度为340℃~380℃，所述第二温度为500℃~600℃。The preparation method according to any one of claims 5-7, characterized in that, the first temperature is 340°C-380°C, and the second temperature is 500°C-600°C.
  9. 根据权利要求8所述的制备方法，其特征在于，所述基底上包含有钼金属层，所述步骤S10共蒸镓和硒时，首先通入硒蒸气使得所述钼金属层的表面形成硒化钼层，然后再通入镓蒸气在所述硒化钼层上共蒸镓和硒。The preparation method according to claim 8, wherein the substrate contains a molybdenum metal layer, and when gallium and selenium are co-evaporated in the step S10, selenium vapor is first introduced so that the surface of the molybdenum metal layer forms selenium molybdenum selenide layer, and then pass gallium vapor to co-evaporate gallium and selenium on the molybdenum selenide layer.
  10. 一种太阳能电池，其特征在于，包括如权利要求1-4任一所述的宽禁带铜镓硒光吸收层。A solar cell, characterized in that it comprises the wide-bandgap copper-gallium-selenide light-absorbing layer according to any one of claims 1-4.
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