Photon-phonon synergistic enhancement method for sputtering damage repair of heterojunction solar cells

Abstract

The present invention discloses a method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergistic enhancement, comprising the following steps: preparing a transparent conductive film on the surface of a hole selective transport layer or an electron selective transport layer, bombarding a silicon substrate with high-energy particles to cause sputtering damage; and softly treating the prepared heterojunction solar cell with strong coupling of photons and microwave-injected phonons. The present invention not only can completely repair the sputtering damage at room temperature through soft photon-phonon coupling treatment, thus broadening the application prospects of magnetron sputtering technology, but also can reduce the interface defect state density, improve the carrier extraction capability, and promote the improvement of the photoelectric conversion efficiency of heterojunction solar cells, and also provides an effective solution for breaking through the bottleneck of temperature stability of undoped heterojunction solar cells.

Description

Technical Field

[0001] The invention relates to the technical field of solar cells, and in particular to a method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergistic enhancement. Background Art

[0002] Silicon heterojunction solar cells not only utilize the manufacturing process of thin-film cells, but also give full play to the material properties of crystalline silicon and amorphous silicon. They have the advantages of high conversion efficiency, low-temperature process, bifacial power generation, and high conversion efficiency (industrialization) ≥ 24%, becoming a research hotspot in the field of solar cells.

[0003] However, silicon heterojunction solar cells are limited by the doping effect of amorphous silicon thin films, and suffer from serious optical parasitic absorption losses and current recombination, which limits the further improvement of photoelectric performance. In recent years, wide-bandgap / high-work-function transition metal oxides (such as MoO x , VO x , WO x ) have been widely studied as alternative doped pa-Si:H films, low work function MgO, ZnO, TiO 2 、LiF、MgF 2 , CsCO 3 Alternative doping with na-Si:H can avoid parasitic absorption loss to a certain extent, and has the advantages of low-temperature process, simple preparation, and no toxic gases.

[0004] In the development of solar cells, transparent conductive oxide (TCO) films have played a vital role. TCO films are used as anti-reflection layers, contact layers, and conductive layers for lateral carrier transport to electrodes. They are widely used in solar cells due to their optoelectronic properties such as wide bandgap, high light transmittance in the visible spectrum, and low resistivity.

[0005] The preparation of TCO thin films currently relies mainly on magnetron sputtering technology, which has the advantages of fast deposition rate, good bonding between the film and the substrate, and good film uniformity. However, the high-energy particles generated during the sputtering process will damage the silicon substrate, resulting in a decrease in the minority carrier lifetime and dark state open circuit voltage, reducing the passivation quality of the silicon wafer and causing the photoelectric performance of the device to decline. Fortunately, sputtering damage has been proven to be repairable in laboratories and industry.

[0006] The existing method of repairing sputtering damage is through post-annealing (generally above 200 degrees Celsius) process. Undoped heterojunction solar cells use transition metal oxides / alkaline earth metals or alkali metal fluorides as hole / electron selective transport layers. However, these materials have poor stability and will denature the materials at high temperatures, resulting in deterioration of the device's photoelectric performance.

[0007] Therefore, it is necessary to develop a method for repairing sputtering damage of heterojunction solar cells with synergistic photon and phonon enhancement to solve the above problems. Summary of the invention

[0008] The purpose of the present invention is to design a photon-phonon synergistically enhanced heterojunction solar cell sputtering damage repair method in order to solve the above problems.

[0009] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0010] A method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy enhancement comprises the following steps:

[0011] A1. Damage removal and surface texturing of the N-type single crystal silicon substrate layer;

[0012] A2, preparing an intrinsic amorphous silicon thin film layer on both sides of an N-type single crystal silicon substrate layer;

[0013] A3, preparing a hole selective transport layer on either side of the amorphous silicon thin film layer;

[0014] A4, preparing an electron selective transport layer on the other side of the amorphous silicon film;

[0015] A5. A transparent conductive film is prepared on the surface of the hole selective transport layer or the electron selective transport layer, and high-energy particles bombard the N-type single crystal silicon substrate to cause sputtering damage;

[0016] A6. Preparing a metal electrode on the surface of a transparent conductive film, or preparing a metal electrode on the surface of a hole selective transport layer or an electron selective transport layer where no transparent conductive film is provided;

[0017] A7. Gentle treatment of heterojunction solar cells using strong coupling of photons and microwave injected phonons;

[0018] A8, splash damage has been completely fixed.

[0019] Specifically, the photon-phonon synergistically enhanced heterojunction solar cell sputtering damage repair method also includes monitoring the minority carrier lifetime and dark state open circuit voltage in the heterojunction solar cell preparation process, and synchronously tracking the sputtering damage and the degree of damage repair.

[0020] Specifically, in step A5, the method of causing sputtering damage includes one or a combination of direct current magnetron sputtering, medium frequency magnetron sputtering, radio frequency magnetron sputtering, and reactive plasma deposition.

[0021] Specifically, the transparent conductive film is ITO (In 2 O 3 :Sn)、IWO(In 2 O3 :W)、ICO(In 2 O 3 :Ce)、FTO(SnO 2 :F)、ITiO(In 2 O 3 :Ti)、IZO(In 2 O 3 :Zn)、AZO(ZnO:Al)、IO:H(In 2 O 3 :H) or a combination of one or more thereof, with a thickness of 1nm-500nm.

[0022] Specifically, the method for strong coupling treatment of photons and microwave injected phonons includes one or a combination of phonon-exciton strong coupling to form quasiparticle repair, photon-exciton polarization to form quasiparticle repair, phonon-phonon coupling to form quasiparticle repair, and photon-photon polariton repair.

[0023] Specifically, excitons are generated by photons and electromagnetic waves. Electromagnetic waves are transverse waves with electromagnetic radiation characteristics, including radio waves, microwaves, infrared rays, visible light, and ultraviolet rays.

[0024] Specifically, the device for generating photons and photon-photon polaritons is: one or a combination of high-quality microresonators, halogen tungsten lamps, iodine tungsten lamps, metal halide lamps, high-pressure sodium lamps, low-pressure sodium lamps, fluorescent lamps, mercury lamps, incandescent lamps, cold cathode fluorescent lamps, LEDs, and OLEDs.

[0025] Specifically, the light sources that generate photons and excitons are: sunlight with a wavelength of 290nm-760nm, yellow light with a wavelength of 590nm-595nm, blue light with a wavelength of 460nm-465nm, red light with a wavelength of 620nm-625nm, green light with a wavelength of 520nm-525nm, violet light with a wavelength of 390nm-400nm, violet light with a wavelength of 365nm, infrared light with a wavelength of 850nm or 940nm, or a combination of the above, and the light intensity of the light source is 10-100000 lux, and the photon-photon polaritons are generated by the combination of the above two photons of different wavelengths.

[0026] Specifically, the microwave injected phonon requires a temperature of 25 o C-100 o C. The atmosphere of microwave-injected phonons is one or a combination of hydrogen, nitrogen, argon, and air, and the phonons in the phonon-phonon coupling are in different quantum states.

[0027] Specifically, the repair time of sputtering damage is 0.1h-300h by softly treating the strong coupling of photons and microwave injected phonons.

[0028] The beneficial effects of the present invention are:

[0029] 1. The present invention can not only completely repair sputtering damage at room temperature through gentle photon-phonon coupling treatment, broaden the application prospects of magnetron sputtering technology, but also reduce the interface defect state density, improve the carrier extraction capability, and promote the improvement of the photoelectric conversion efficiency of heterojunction solar cells. At the same time, it also provides an effective solution for breaking through the temperature stability bottleneck of undoped heterojunction solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The process flow of repairing sputtering damage by photon-phonon coupling treatment based on the method of the present invention; wherein a, b, and c correspond to three processing states respectively;

[0031] Figure 2 A graph showing the relationship between the photon-phonon coupling treatment time and the minority carrier lifetime (τ) of the synchronous test of the photon-phonon coupling treatment for repairing sputtering damage based on the method of the present invention;

[0032] Figure 3 The photon-phonon coupling treatment time-dark state open circuit voltage ( iV oc ) Relationship graph;

[0033] Figure 4 The structure diagram of the heterojunction solar cell with photon-phonon synergy enhancement based on the method of the present invention and the structure diagram of the cell after damage repair; wherein a and b correspond to two processing states respectively;

[0034] Figure 5 A heterojunction solar cell with photon-phonon synergistic enhancement based on the method of the present invention;

[0035] (a) is the relationship between photon-phonon coupling processing time and open circuit voltage;

[0036] (b) is the relationship curve between photon-phonon coupling processing time and photoelectric conversion efficiency.

[0037] Description of Reference Numerals

[0038] In the figure: 11-first metal electrode, 12-second metal electrode, 21-transparent conductive film, 22-transparent conductive film after photon-phonon coupling treatment, 3-hole selective transport layer, 4-intrinsic amorphous silicon film. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0042] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0043] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0044] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0046] A method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy enhancement comprises the following steps:

[0047] A1. Damage removal and surface texturing of the N-type single crystal silicon substrate layer;

[0048] A2, depositing an intrinsic amorphous silicon thin film layer 4 on both sides of the N-type single crystal silicon substrate layer, which is ia-Si:H / nc-Si / ia-Si:H;

[0049] A3. Prepare a hole selective transport layer 3 on either side of the amorphous silicon thin film layer; the hole selective transport layer material is boron-doped pa-Si:H or high work function MoO x , VO x , WO x 、NiO x CrO 3 , CuO, CuI, PEDOT:PSS or a combination of them;

[0050] A4. Deposit an electron selective transport layer on the other side of the amorphous silicon film; the electron selective transport layer material is phosphorus-doped na-Si:H or low work function LiF, MgF 2 , CaF 2 , YF 3 , MgO, ZnO, TiN, TiO 2 or LiF and BeF 2 MgF 2 , CaF 2 , SrF 2 , BaF 2 , RaF 2 , BeO, MgO, CaO, Be, Mg, Ca, Sr, Ba, Ra, etc., or a combination of at least one or more thereof;

[0051] A5. A transparent conductive film is prepared on the surface of the hole selective transport layer or the electron selective transport layer (preparing a transparent conductive film on the surface of the hole selective transport layer or the electron selective transport layer means that, depending on the different battery structures, sometimes a transparent conductive film may not be prepared for the electron selective transport layer, but sometimes it is required), and high-energy particles bombard the N-type single crystal silicon substrate to cause sputtering damage; in the preparation of the transparent conductive film, it is inevitable that high-energy particles bombard the silicon substrate to cause sputtering damage, which ultimately leads to poor photoelectric performance of the battery.

[0052] A6, metal electrodes (a first metal electrode 11 and a second metal electrode 12) are respectively prepared on the surface of the transparent conductive film on the hole selective transport layer and the electron selective transport layer without the transparent conductive film;

[0053] A7, gently treat the N-type single crystal silicon substrate using strong coupling of photons and microwave injected phonons;

[0054] A8, splash damage has been completely fixed.

[0055] The method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy also includes monitoring the minority carrier lifetime and dark open circuit voltage in the heterojunction solar cell preparation process, and synchronously tracking the sputtering damage and the degree of damage repair. Specifically, it includes: monitoring the minority carrier lifetime (τ) and dark open circuit voltage (i-Voc) in the heterojunction solar cell preparation process before step A5, after step A5, and after step A7, and synchronously tracking the sputtering damage and the degree of damage repair, with the purpose of adjusting the working time of each stage according to the monitoring results.

[0056] In step A5, the method of causing sputtering damage includes one or a combination of direct current (DC) magnetron sputtering, medium frequency (MF) magnetron sputtering, radio frequency (RF) magnetron sputtering, and reactive plasma deposition (RPD).

[0057] The transparent conductive film is ITO (In 2 O 3 :Sn)、IWO(In 2 O 3 :W)、ICO(In 2 O 3 :Ce)、FTO(SnO 2 :F)、ITiO(In 2 O 3 :Ti)、IZO(In 2 O 3 :Zn)、AZO(ZnO:Al)、IO:H(In 2 O 3 :H) or a combination of one or more thereof, with a thickness of 1nm-500nm.

[0058] The method for strong coupling treatment of photons and microwave injected phonons includes one or a combination of phonon-exciton strong coupling to form quasiparticle repair, photon-exciton polarization to form quasiparticle repair, phonon-phonon coupling to form quasiparticle repair, and photon-photon polariton repair.

[0059] Excitons are generated by photons and electromagnetic waves. Electromagnetic waves are transverse waves with electromagnetic radiation characteristics. Electromagnetic waves include radio waves, microwaves, infrared rays, visible light, and ultraviolet rays.

[0060] The device for generating photons and photon-photon polaritons is: one or a combination of high-quality microresonators, halogen tungsten lamps, iodine tungsten lamps, metal halide lamps, high-pressure sodium lamps, low-pressure sodium lamps, fluorescent lamps, mercury lamps, incandescent lamps, cold cathode fluorescent lamps, LEDs, and OLEDs.

[0061] The light sources for generating photons and excitons are: sunlight with a wavelength of 290nm-760nm, yellow light with a wavelength of 590nm-595nm, blue light with a wavelength of 460nm-465nm, red light with a wavelength of 620nm-625nm, green light with a wavelength of 520nm-525nm, violet light with a wavelength of 390nm-400nm, violet light with a wavelength of 365nm, infrared light with a wavelength of 850nm or 940nm, or a combination of the above. The illumination intensity of the light source is 10-100000 lux, and the photon-photon polaritons are generated by the combination of the above two photons with different wavelengths.

[0062] The required temperature for microwave injected phonons is 25 o C-100 o C. The atmosphere of microwave-injected phonons is one or a combination of gases such as hydrogen, nitrogen, argon, and air, and the phonons in the phonon-phonon coupling are in different quantum states.

[0063] The strong coupling of photons and microwave injected phonons gently repairs sputtering damage, with a repair time of 0.1h-300h.

[0064] Example:

[0065] like Figure 1 As shown, the invention proposes a method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy, which has the following steps:

[0066] (1) The minority carrier lifetime instrument was used to measure the minority carrier lifetime of n-type single crystal silicon substrate (ia-Si:H / nc-Si / ia-Si:H) with intrinsic amorphous silicon thin film passivation layer (ia-Si:H) on both sides. τ ) and dark open circuit voltage ( i- V oc );

[0067] (2) If Figure 1 S1 in the figure represents the preparation of zinc-doped indium oxide (IZO) transparent conductive film to form ia-Si:H / nc-Si / ia-Si:H / IZO substrate;

[0068] (3) If Figure 1 S2 in the figure represents the minority carrier lifetime of the ia-Si:H / nc-Si / ia-Si:H / IZO substrate measured first ( τ ) and dark open circuit voltage ( iV oc ),

[0069] (4) The ia-Si:H / nc-Si / ia-Si:H / IZO substrate is then gently treated by strong coupling of photons and microwave injected phonons. Depending on the different preparation methods of the IZO film, different treatment methods are used, including one or a combination of phonon-exciton strong coupling to form quasiparticle repair, photon-exciton polariton to form quasiparticle repair, phonon-phonon coupling to form quasiparticle repair, and photon-photon polariton repair.

[0070] (5) Finally, the minority carrier lifetime (τ) and dark state open circuit voltage ( iV oc ), at which point the sputtering damage will be completely repaired;

[0071] The relationship between minority carrier lifetime (τ) and dark state open circuit voltage ( iV oc ) Figure 2 and Figure 3 As shown;

[0072] like Figure 4 As shown, the invention proposes a heterojunction solar cell with photon-phonon synergistic enhancement, and the structure of the heterojunction solar cell is as follows:

[0073] Ag / IZO / MoO x / ia-Si:H / nc-Si / ia-Si:H / LiF x / MgF x O y / Mg / Ag, wherein Ag is metallic silver, IZO is a transparent conductive film of indium oxide doped with zinc (including a transparent conductive film 21 and a transparent conductive film 22 after photon-phonon coupling treatment), MoO x is a molybdenum oxide film, ia-Si:H is an intrinsic amorphous silicon film, nc-Si is an n-type single crystal silicon substrate, LiF x For lithium fluoride film, MgF x O y It is a mixed film formed by Mg-FO, and Mg is metallic magnesium. Figure 5 As shown, a graph showing the relationship between the photon-phonon coupling treatment time and the open circuit voltage in a heterojunction solar cell with photon-phonon synergistic enhancement (a); and a graph showing the relationship between the photon-phonon coupling treatment time and the photoelectric conversion efficiency (b).

[0074] The present invention can repair sputtering damage at low temperature, while the traditional method of repairing sputtering damage requires more than 200o C annealing is suitable for silicon heterojunction solar cells, but not for undoped heterojunction solar cells, which greatly limits the application of magnetron sputtering technology. For example, perovskite cells and organic thin-film cells in other new solar cells are also very strict about temperature and cannot withstand temperatures above 200 °C. o C temperature.

[0075] 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 technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Photon-phonon synergistic heterojunction solar cell sputtering damage repair method, It is characterized in that Includes steps: A1. Damage removal and surface texturing of the N-type single crystal silicon substrate layer; A2, preparing an intrinsic amorphous silicon thin film layer on both sides of an N-type single crystal silicon substrate layer; A3, preparing a hole selective transport layer on either side of the amorphous silicon thin film layer; A4, preparing an electron selective transport layer on the other side of the amorphous silicon film; A5. A transparent conductive film is prepared on the surface of the hole selective transport layer or the electron selective transport layer, and high-energy particles bombard the N-type single crystal silicon substrate to cause sputtering damage; A6. Preparing a metal electrode on the surface of a transparent conductive film, or preparing a metal electrode on the surface of a hole selective transport layer or an electron selective transport layer where no transparent conductive film is provided; A7. Gentle treatment of heterojunction solar cells by strong coupling of photons and microwave injected phonons; methods for strong coupling of photons and microwave injected phonons, including one or a combination of phonon-exciton strong coupling to form quasiparticle repair, photon-exciton polarization to form quasiparticle repair, phonon-phonon coupling to form quasiparticle repair, photon-photon polariton repair; the required temperature of microwave injected phonons is 25 o C-100 o C, the atmosphere of microwave-injected phonons is one or a combination of hydrogen, nitrogen, argon, and air, and the phonons in the phonon-phonon coupling are in different quantum states; A8, splash damage has been completely fixed.

2. The method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy according to claim 1, It is characterized in that It also includes monitoring the minority carrier lifetime and dark state open circuit voltage in the heterojunction solar cell preparation process, and simultaneously tracking the sputtering damage and the extent of damage repair.

3. The method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy according to claim 1, It is characterized in that In step A5, the method of causing sputtering damage includes one or a combination of direct current magnetron sputtering, medium frequency magnetron sputtering, radio frequency magnetron sputtering, and reactive plasma deposition.

4. The method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy according to claim 1, It is characterized in that The transparent conductive film is ITO (In 2 O 3 :Sn)、IWO(In 2 O 3 :W)、ICO(In 2 O 3 :Ce)、FTO(SnO 2 :F)、ITiO(In 2 O 3 :Ti)、IZO(In 2 O 3 :Zn)、AZO(ZnO:Al)、IO:H(In 2 O 3 :H) or a combination of one or more thereof, with a thickness of 1nm-500nm.

5. The method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy according to claim 1, Features: Excitons are generated by photons and electromagnetic waves. Electromagnetic waves are transverse waves with electromagnetic radiation characteristics. Electromagnetic waves include radio waves, microwaves, infrared rays, visible light, and ultraviolet rays.

6. The method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy according to claim 1, Features: The device for generating photons and photon-photon polaritons is: one or a combination of high-quality microresonators, halogen tungsten lamps, iodine tungsten lamps, metal halide lamps, high-pressure sodium lamps, low-pressure sodium lamps, fluorescent lamps, mercury lamps, incandescent lamps, cold cathode fluorescent lamps, LEDs, and OLEDs.

7. The method for repairing sputtering damage of heterojunction solar cells with photon-phonon synergy according to claim 1, Features: The light sources for generating photons and excitons are: sunlight with a wavelength of 290nm-760nm, yellow light with a wavelength of 590nm-595nm, blue light with a wavelength of 460nm-465nm, red light with a wavelength of 620nm-625nm, green light with a wavelength of 520nm-525nm, violet light with a wavelength of 390nm-400nm, violet light with a wavelength of 365nm, infrared light with a wavelength of 850nm or 940nm, or a combination of the above two. The illumination intensity of the light source is 10-100000 lux, and the photon-photon polaritons are generated by the combination of the above two photons with different wavelengths.

8. The method for repairing sputtering damage of a heterojunction solar cell with synergistic effect of photons and phonons according to claim 1, characterized in that: the repair time for repairing sputtering damage by soft treatment of strong coupling between photons and phonons injected by microwaves is 0.1 h - 300 h.

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