A method for low-damage deposition of transparent conductive films and photovoltaic devices

Abstract

A method for depositing transparent conductive film with low damage and photovoltaic device. The method separates the control of plasma ignition stage and deposition stage, and realizes stage energy management: first, in the state of not exposed or only low exposed to the main deposition flux, the first discharge parameter is higher than the ignition threshold value to stabilize the ignition; then the discharge parameter is continuously or stepwise reduced to the second discharge parameter by at least two stages, so that the plasma enters the low heat load and low bombardment energy state close to the critical maintenance discharge; finally, the transparent conductive oxide is deposited on the surface of the plasma or the heat sensitive functional layer to form a transparent conductive film. The invention decouples the ignition stability and low damage deposition, significantly reduces the high-energy particle bombardment, substrate temperature rise and interface element intermixing, and can obtain a transparent electrode with low sheet resistance, high transmittance and low interface recombination in the case of reducing or canceling the buffer layer, which is suitable for various stacked solar cells and related photovoltaic devices.

Description

Technical Field

[0001] This invention relates to the fields of photovoltaic devices, semiconductor devices, and vacuum coating technology, and particularly to a low-damage plasma deposition method for depositing a transparent conductive film on the surface of a functional layer susceptible to plasma damage, and a photovoltaic device prepared using this method. Background Technology

[0002] Transparent conductive layers are key functional layers in perovskite solar cells, perovskite / silicon tandem solar cells, perovskite / perovskite tandem solar cells, transparent photovoltaic devices, semi-transparent photovoltaic devices, perovskite light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), quantum dot LEDs, and various other optoelectronic devices. Transparent conductive layers typically need to simultaneously possess high light transmittance, low sheet resistance, a suitable work function, good adhesion, and low contact resistance with the underlying carrier transport layer. Commonly used transparent conductive films include indium tin oxide (ITO), indium zinc oxide (ITO), indium oxide (ITO), tungsten-doped indium oxide (ITO), and aluminum-doped zinc oxide (ZNO).

[0003] Existing transparent conductive layers are commonly fabricated using processes such as magnetron sputtering, reactive magnetron sputtering, and reactive plasma deposition. These processes typically rely on plasma to generate deposited species, and the deposition process inevitably involves high-energy ions, high-energy neutral particles, secondary electrons, ultraviolet radiation, and heat accumulation. For glass, silicon wafers, or stable inorganic thin films, these effects are generally acceptable; however, for sensitive functional layers such as perovskite layers, fullerene derivative layers, organic transport layers, self-assembled monolayers, and two-dimensional perovskite passivation layers, the aforementioned thermal and plasma bombardment effects may lead to increased interface defects, elemental mismixing, chemical bond disruption, increased nonradiative recombination, reduced carrier lifetime, luminescence quenching, decreased external quantum efficiency, decreased device fill factor, or shortened operating lifetime.

[0004] To avoid damage during transparent conductive layer deposition, existing perovskite / silicon tandem solar cells, semi-transparent solar cells, and transparent light-emitting devices typically introduce a buffer layer, such as atomic layer deposition of SnO, between the sensitive functional layer and the transparent conductive film. x Evaporated oxides, organic buffer layers, or composite buffer layers can mitigate plasma damage, but this approach introduces additional equipment, processes, longer cycle times, and higher material consumption. In particular, atomic layer deposition processes typically have low deposition rates and high equipment costs, and buffer layers can also introduce problems such as parasitic absorption, increased interfacial resistance, and a narrowed process window.

[0005] Directly cancel the buffer layer and in C 60Depositing transparent conductive films near organic transport layers, quantum dot layers, light-emitting layers, or other sensitive functional layers is an effective way to simplify device structures, reduce costs, and improve optical utilization. However, the initial ignition stage of conventional sputtering or conventional plasma deposition often requires high power or high current, which can easily lead to transient thermal shock and high-energy particle bombardment. If ignition is performed directly with low power, low current, or low gas flow, problems such as ignition failure, unstable discharge, low deposition rate, and insufficient film density and electrical properties are likely to occur. Therefore, simply reducing the deposition power cannot simultaneously solve the contradictory problems of "plasma stability" and "low-damage deposition".

[0006] Existing technologies include low-power sputtering, remote plasma, adding buffer layers, increasing target-substrate distance, and reducing substrate bias. However, most of these methods treat the ignition and deposition processes as the same process window or still rely on buffer layer protection, failing to decouple "stable ignition" and "low-damage deposition" from a control logic perspective. Therefore, it is necessary to propose a general method that can first stably establish plasma, then adjust the plasma to a near-critical sustaining discharge state, and subsequently deposit a transparent conductive film under low-bombardment conditions. Summary of the Invention

[0007] This invention aims to solve at least one of the following technical problems: First, to solve the problem of plasma's influence on perovskite and C during the deposition of transparent conductive films. 60 The project addresses several key issues: First, it addresses damage to sensitive functional layers such as organic transport layers, self-assembled monolayers, passivation layers, quantum dot layers, organic light-emitting layers, and perovskite light-emitting layers. Second, it solves problems related to difficulty in direct ignition at low power or low current, unstable discharge, and poor batch-to-batch repeatability. Third, it addresses the dependence on ALD-SnO. x The buffer layer leads to complex device structures, long deposition cycles, high equipment costs, and increased parasitic absorption. Fourth, it addresses the challenge of simultaneously achieving low-damage deposition and low sheet resistance, high transmittance, high mobility, and good energy level matching in transparent conductive films. Fifth, it provides a general process control strategy that is not limited to a single reactive plasma deposition equipment and can be extended to magnetron sputtering and other plasma coating equipment.

[0008] To address the aforementioned technical problems, this invention provides a low-damage transparent conductive film deposition method. The technical concept involves separating and controlling the "ignition stage" and the "deposition stage": first, a plasma is established using a first discharge parameter sufficient to stabilize ignition; then, with the substrate shielded or avoiding the main deposition area, the discharge parameter is reduced to a second discharge parameter close to the critical maintenance discharge parameter through at least two stages; finally, a transparent conductive film is deposited under the second discharge parameter.

[0009] Because a higher discharge parameter is used in the ignition stage, plasma can be reliably established; and because a reduced second discharge parameter is used in the deposition stage, the particle bombardment, ultraviolet irradiation, electron bombardment, and heat accumulation on the functional layer, which is susceptible to plasma damage, are significantly reduced. Therefore, this invention can simultaneously achieve stable discharge, low-damage interface, and good transparent conductive film performance.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for low-damage deposition of a transparent conductive film includes the following steps:

[0012] A, providing a substrate to be deposited, wherein the surface of the substrate to be deposited includes a plasma-sensitive functional layer;

[0013] B. Introduce working gas and optional reactive gas into a vacuum chamber, and establish a stable plasma with a first discharge parameter when the substrate to be deposited is not exposed to the main deposition flux or is only exposed to a state below the film formation flux. The first discharge parameter is higher than the ignition threshold of the plasma.

[0014] C. After the stable plasma is established, the discharge parameter is reduced from the first discharge parameter to the second discharge parameter through at least two consecutive or stepwise steps. The second discharge parameter is higher than the plasma extinguishing threshold and lower than the first discharge parameter.

[0015] D, Under the second discharge parameters, a transparent conductive material is deposited onto the surface of the plasma-sensitive functional layer of the substrate to be plated, forming a transparent conductive film;

[0016] In step C, the reduction of discharge parameters includes reducing at least one of the following: discharge current, discharge power, target power density, target voltage, ion beam energy, pulse duty cycle, working gas flow rate, reactive gas flow rate, substrate bias voltage, and plasma source power; the plasma bombardment intensity experienced by the plasma-sensitive functional layer during the formation of the transparent conductive film is lower than that in step B.

[0017] In one embodiment, the method is carried out using a reactive plasma deposition apparatus.

[0018] In this embodiment, the reactive plasma deposition equipment uses at least one of InOx ceramic particles, IZO ceramic particles, ITO ceramic particles, IWO ceramic particles, AZO ceramic particles, and GZO ceramic particles as the deposition source material.

[0019] In this embodiment, step B establishes a stable plasma using a first discharge current, step C gradually reduces the discharge current to a second discharge current, and step D deposits the transparent conductive film under the second discharge current. Specifically, a stable plasma is first established using a first discharge current of 20 A to 80 A, then the discharge current is gradually reduced to a second discharge current of 3 A to 30 A, and InO is deposited under the second discharge current. x Transparent conductive films such as IZO, ITO, or IWO are used. Preferably, the first discharge current is 25 A to 60 A, and the second discharge current is 3 A to 30 A; more preferably, the first discharge current is 30 A to 40 A, and the second discharge current is 10 A to 20 A. More specifically, in step C, the discharge current is first reduced from 30 A to 40 A to 20 A to 30 A and held for 10 to 300 seconds; then reduced to 15 A to 25 A and held for 10 to 300 seconds; then reduced to 10 A to 20 A and held for 30 to 900 seconds; then step D is performed. The thickness of the transparent conductive film deposited in step D is 20 nm to 50 nm, the sheet resistance is not higher than 150 Ω / □, and the average transmittance at 400 nm to 1200 nm is not less than 80%.

[0020] In a more specific embodiment, the working gas includes at least one of Ar, He, Ne, Kr, and Xe; the reactant gas includes at least one of O2, H2O, O3, N2O, CO2, H2, N2, and NH2. Preferably, the working gas is Ar, and the reactant gas is O2. The Ar flow rate can be from 5 sccm to 500 sccm, preferably from 10 sccm to 300 sccm, and more preferably from 20 sccm to 150 sccm; the flow rate ratio of O2 to Ar can be from 0 to 0.2, preferably from 0.005 to 0.1, and more preferably from 0.01 to 0.06. In this embodiment, in step C, the Ar flow rate is reduced synchronously or asynchronously in stages with the discharge current. Specifically, the discharge current can be reduced step by step along the path 35A→25A→20A→15A, or along the path 40A→30A→20A→15A, 30A→25A→20A→15A, or other equivalent paths.

[0021] In another embodiment, the method is implemented using a magnetron sputtering apparatus. It is applicable to DC magnetron sputtering, RF magnetron sputtering, IF magnetron sputtering, pulsed DC magnetron sputtering, reactive magnetron sputtering, and high-power pulsed magnetron sputtering.

[0022] In this embodiment, step B initiates ignition at a first target power density; step C gradually reduces the target power density, target voltage, pulse duty cycle, or substrate bias to a second target power density; and step D deposits the transparent conductive film at the second target power density. Specifically, in step B, the baffle is first closed, and the target material is ignited and pre-sputtered at a higher target power density; in step C, after the discharge stabilizes, the target power density, target voltage, pulse duty cycle, or substrate bias is gradually reduced; in step D, after the discharge stabilizes at a lower power density, the baffle is opened, and a transparent conductive film is deposited on the sensitive functional layer. The high-energy particle flux reaching the plasma sensitive functional layer is reduced by at least one of the following methods: increasing the working pressure, increasing the target-substrate distance, using off-axis deposition, setting up a plasma confinement device, setting up a neutral particle blocking device, or using remote sputtering, while ensuring that the substrate to be deposited is in a floating, grounded, zero-biased, or negative bias absolute value not exceeding 20 V.

[0023] In this embodiment, the first target power density is 0.5 W / cm². 2 Up to 20W / cm 2 Preferably 1W / cm 2 Up to 8W / cm 2 The second target power density is 0.01 W / cm². 2 Up to 5W / cm 2 The preferred value is 0.05 W / cm. 2 Up to 2W / cm 2 In step D, the substrate to be plated is in a floating, grounded, zero bias, or negative bias state with an absolute value not exceeding 20 V.

[0024] In another embodiment, the method is implemented using any one of plasma-assisted evaporation, ion beam-assisted deposition, hollow cathode discharge deposition, electron beam evaporation combined with plasma activation, and remote plasma deposition; wherein in step C, low-damage deposition is achieved by reducing the plasma source power, ion beam energy, ion beam current density, reactive gas activation intensity, or substrate bias.

[0025] This invention further provides a method for fabricating a photovoltaic device, comprising: forming a semi-finished photovoltaic device including a light-absorbing layer and a carrier transport layer; forming a transparent conductive film on the carrier transport layer using the above method, wherein the carrier transport layer is in direct contact with the transparent conductive film. In the interface between the carrier transport layer and the transparent conductive film of the obtained photovoltaic device, the diffusion depth of the metal element in the transparent conductive film towards the carrier transport layer side is less than 50% of the thickness of the carrier transport layer; preferably less than 30%; more preferably less than 20%. The photovoltaic device is a single-junction perovskite solar cell, a perovskite / silicon tandem solar cell, a perovskite / perovskite tandem solar cell, a perovskite / CIGS tandem solar cell, a perovskite / crystalline silicon four-terminal tandem solar cell, a semi-transparent perovskite solar cell, a flexible perovskite solar cell, or a photovoltaic module.

[0026] In another embodiment, the transparent conductive film employs a bilayer or multilayer structure. In the bilayer structure, the first sublayer, located closer to the sensitive functional layer, is a low-damage interface sublayer with a thickness of 0.2 nm to 20 nm; the second sublayer, located farther from the sensitive functional layer, is a low-resistance host sublayer with a thickness of 5 nm to 500 nm. The interface sublayer prioritizes low damage and energy level matching, while the host sublayer prioritizes low sheet resistance and high transmittance.

[0027] In another embodiment, the photovoltaic device is a perovskite / silicon tandem solar cell. This cell may sequentially include a crystalline silicon base cell, a composite contact layer, a hole transport layer, a perovskite absorber layer, a surface passivation layer, and a CS layer. 60 Electron transport layer, InO x Transparent conductive film and metal grid lines. Where C... 60 Electron transport layer and InO x The transparent conductive films are in direct contact, without any ALD-SnO between them. x Buffer layer. By adjusting the oxygen partial pressure, InO x The membrane exhibits high mobility, appropriate carrier concentration, and compatibility with C. 60 The energy level position matched by the electron transport layer, thereby reducing C 60 / InO x The contact resistance of the interface improves carrier extraction. The C mentioned above... 60 The electron transport layer has a thickness of 5 nm to 10 nm, and the InO x The thickness of the transparent conductive film is 20nm to 50nm.

[0028] The advantages of this invention are

[0029] First, this invention decouples plasma ignition stability from low-damage deposition. A higher discharge parameter is used during the ignition stage to avoid direct ignition failure at low power; the deposition stage uses a second discharge parameter that is reduced in stages to minimize damage to the sensitive functional layer.

[0030] Secondly, this invention can significantly reduce substrate temperature rise, particle bombardment, and interfacial element mixing, which is beneficial for maintaining the perovskite / C ratio. 60 Chemical integrity of interfaces such as perovskite / organic transport layer and perovskite / passivation layer.

[0031] Third, this invention can reduce or eliminate ALD-SnO x Buffer layers can shorten the manufacturing process, reduce material consumption and equipment usage, and reduce parasitic absorption caused by the buffer layer.

[0032] Fourth, this invention utilizes InO x By controlling the oxygen partial pressure and electrical properties of transparent conductive materials such as IZO and ITO, high transmittance, low sheet resistance, high mobility, and suitable energy level matching can be obtained simultaneously.

[0033] Fifth, this invention is not limited to RPD equipment, but can be applied to a variety of equipment such as magnetron sputtering, reactive magnetron sputtering, pulsed magnetron sputtering, remote plasma deposition, ion beam assisted deposition, and plasma assisted evaporation, and has strong industrial applicability.

[0034] Sixth, the present invention is suitable for the production of large-area batteries and modules, and can achieve uniform deposition through multi-zone gas, multi-zone power supply, multi-cathode arrangement, substrate transport and feedback control. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the process for the low-damage transparent conductive film deposition method of the present invention.

[0036] Figure 2 This is a schematic diagram of the change of discharge parameters over time in this invention, including the ignition stage, the staged energy reduction stage, and the low-damage deposition stage.

[0037] Figure 3 Schematic diagram of the control process of magnetron sputtering equipment

[0038] Figure 4 Schematic diagrams of single-layer, bilayer, and gradient structures of transparent conductive films.

[0039] Figure 5 This is a schematic diagram of a perovskite / silicon tandem solar cell structure using the method of the present invention.

[0040] Figure 6 To employ the method of this invention in perovskite / C 60SEM diagram of a transparent conductive film directly deposited on a stack of layers. Detailed Implementation

[0041] The present invention will be described below with reference to specific embodiments. It should be understood that the following embodiments are for explaining the present invention, and not for limiting the present invention. Any equivalent substitutions or conventional changes made to the deposition materials, equipment types, parameter ranges, and device structures under the concept of the present invention shall fall within the protection scope of the present invention.

[0042] See Figure 1 The flowchart shown illustrates that this invention provides a method for low-damage deposition of a transparent conductive film, comprising the following steps:

[0043] A, providing a substrate to be deposited, wherein the surface of the substrate to be deposited includes a plasma-sensitive functional layer;

[0044] B. Introduce working gas and optional reactive gas into a vacuum chamber, and establish a stable plasma with a first discharge parameter when the substrate to be deposited is not exposed to the main deposition flux or is only exposed to a state below the film formation flux. The first discharge parameter is higher than the ignition threshold of the plasma.

[0045] C. After the stable plasma is established, the discharge parameter is reduced from the first discharge parameter to the second discharge parameter through at least two consecutive or stepwise steps. The second discharge parameter is higher than the plasma extinguishing threshold and lower than the first discharge parameter.

[0046] The reduction of discharge parameters includes reducing at least one of the following: discharge current, discharge power, target power density, target voltage, ion beam energy, pulse duty cycle, working gas flow rate, reactive gas flow rate, substrate bias, and plasma source power.

[0047] D, Under the second discharge parameters, a transparent conductive material is deposited onto the surface of the plasma-sensitive functional layer of the substrate to be plated, forming a transparent conductive film;

[0048] The plasma bombardment intensity experienced by the plasma-sensitive functional layer during the formation of the transparent conductive film is lower than that in step B.

[0049] In an embodiment of the present invention, the method is implemented using a reactive plasma deposition apparatus; in step B, a stable plasma is established with a first discharge current; in step C, the discharge current is reduced in stages to a second discharge current; and in step D, the transparent conductive film is deposited under the second discharge current.

[0050] In the embodiments of the present invention, the method is implemented using a magnetron sputtering device, which is a DC magnetron sputtering device, a radio frequency magnetron sputtering device, a medium frequency magnetron sputtering device, a pulsed DC magnetron sputtering device, a reactive magnetron sputtering device, a high power pulsed magnetron sputtering device, or a combination thereof; in step B, ignition is initiated at a first target power density; in step C, the target power density, target voltage, pulse duty cycle, or substrate bias voltage is reduced in stages to a second target power density; and in step D, the transparent conductive film is deposited at the second target power density.

[0051] In the embodiments of the present invention, the method is implemented by any one of plasma-assisted evaporation, ion beam-assisted deposition, hollow cathode discharge deposition, electron beam evaporation combined with plasma activation, and remote plasma deposition; in step C, low-damage deposition is achieved by reducing the plasma source power, ion beam energy, ion beam current density, reactive gas activation intensity, or substrate bias.

[0052] The implementation method of this invention will be further explained below through specific examples.

[0053] Example 1: Reactive plasma deposition of InO x transparent conductive film

[0054] We provide perovskite / silicon tandem semi-finished solar cells. These semi-finished cells include a crystalline silicon base, a composite contact layer, a hole transport layer, a wide-bandgap perovskite absorber layer, a surface passivation layer, and a C2 layer. 60 Electron transport layer. C 60 The thickness of the electron transport layer can be any thickness in the range of 5nm to 10nm.

[0055] The semi-finished battery is placed in the vacuum chamber of the reactive plasma deposition apparatus. After the chamber is evacuated, Ar is introduced as the working gas and O2 is introduced as the reactive gas. The Ar flow rate can be set from 20 sccm to 150 sccm, and the O2 to Ar flow rate ratio can be set from 0.01 to 0.06.

[0056] Ignition Stage: The deposition baffle is closed to prevent the semi-finished cell from being exposed to the main deposition flux. A stable plasma is established using a discharge current of 30A to 40A. This stage is mainly used to overcome the difficulty of direct ignition at low currents.

[0057] Phased energy reduction stage: After plasma stabilization, the discharge current and Ar flux are gradually reduced. A schematic diagram illustrating the changes in discharge parameters over time is shown below. Figure 2 As shown, the discharge current can adopt any of the following energy reduction paths:

[0058] A 35 A 25 A 20 A 15 A B 40 A 30 A 20 A 15 A C 30 A 25 A 20 A 15 A

[0059] Each stage can be maintained for 10 to 300 seconds, and the final low-current stage can be maintained for 30 to 900 seconds to ensure that the plasma enters a stable, low-damage state. If the equipment cavity is large or the gas response is slow, the maintenance time can be appropriately extended.

[0060] Deposition stage: After the plasma stabilizes at a low current of 10 A to 20 A, the deposition baffle is opened to allow InO to deposit. x Deposition to C 60 On the surface of the layer, InO with a thickness of 20 nm to 50 nm is formed. x Transparent conductive film. During the deposition process, the substrate temperature is preferably controlled below 45 ℃, but can also be controlled below 60 ℃ or 80 ℃ depending on the material's tolerance.

[0061] Through this method, C 60 Electron transport layer and InO x The transparent conductive films are in direct contact, and no ALD-SnO is required between them. x Buffer layer. Because the deposition stage is characterized by low current, low heat accumulation, and low particle bombardment, it can reduce C. 60 / InO x Interfacial element mixing and chemical state changes.

[0062] Example 2: Reactive plasma deposition of IZO transparent conductive film

[0063] This embodiment is basically the same as Embodiment 1, except that the deposition source material is IZO ceramic particles, forming an IZO transparent conductive film.

[0064] The ignition current can be 25 A to 40 A, and the deposition current can be 10 A to 20 A. The Ar flow rate can be 20 sccm to 150 sccm, and the O2 to Ar flow rate ratio can be 0 to 0.1. By gradually reducing the current and gas flow rate, deposition can be achieved at C... 60 A low-damage IZO transparent conductive film is formed on PCBM or other electron transport layers.

[0065] IZO transparent conductive films are suitable for devices with different requirements for work function, carrier concentration, or transmittance. Compared with conventional high-power sputtering, this embodiment can reduce post-deposition perovskite luminescence quenching and interface recombination.

[0066] Example 3: Reactive plasma deposition of ITO or IWO transparent conductive films

[0067] This embodiment is basically the same as Embodiment 1, except that the deposition source material is ITO ceramic particles or IWO ceramic particles. By adjusting the O2 / Ar flow ratio and the final stage deposition current, low sheet resistance ITO transparent conductive film or high mobility IWO transparent conductive film can be obtained respectively.

[0068] When used in perovskite / C 60 When performing sensitive layer stacking, it is preferable to first deposit a low-damage interface sublayer of 0.5 nm to 10 nm under low current, followed by the deposition of the main conductive sublayer. The interface sublayer can be made of the same material as the main conductive sublayer, or it can be made of a different material.

[0069] Example 4: Low-damage deposition of ITO, IZO or InO by magnetron sputtering x transparent conductive film

[0070] Provides a perovskite absorber layer and C 60 The substrate to be deposited for the electron transport layer. The substrate to be deposited is fixed to the substrate stage of the magnetron sputtering equipment. The substrate stage is grounded, floating, or subjected to a low bias voltage with an absolute value not exceeding 20 V.

[0071] Ar and optional O2 are introduced into the cavity. The front baffle of the substrate is closed for ITO, IZO, and InO. x IWO or AZO targets are used for ignition and pre-sputtering. The ignition stage uses a first target power density, which can be 1 W / cm³. 2 Up to 8 W / cm 2 .

[0072] After the plasma stabilizes, the target power density is reduced in stages with the baffle closed. The control process of the magnetron sputtering equipment is as follows: Figure 3 As shown.

[0073] The Beginning Stage 100% 10 seconds to 300 seconds Phase I of Energy Reduction 70% to 80% 5 seconds to 300 seconds Phase II of Energy Reduction 40% to 60% 5 seconds to 300 seconds Three stages of energy reduction 10% to 40% 10 seconds to 900 seconds Deposition stage 10% to 40% Determined by target thickness

[0074] Once the target voltage, discharge current, and cavity pressure have stabilized, open the baffle at C. 60 A transparent conductive film is deposited on the electron transport layer. The power density of the second target can be 0.05 W / cm². 2 Up to 2 W / cm 2 .

[0075] To further reduce damage, at least one of the following measures can be adopted: substrate floating or zero bias; target-substrate distance of 80 mm to 300 mm; working pressure of 0.2 Pa to 5 Pa; off-axis sputtering; setting a confined magnetic field; using pulsed DC low duty cycle; and forming an interface sublayer with lower power density within 5 nm before deposition.

[0076] This embodiment illustrates that the present invention is not limited to reactive plasma deposition equipment. In magnetron sputtering, the same low-damage deposition objective can be achieved by employing a control logic of "high-power stable ignition—staged power reduction under shielding—low-power stable deposition".

[0077] Example 5: Low-damage deposition by high-power pulsed magnetron sputtering

[0078] In high-power pulsed magnetron sputtering equipment, the plasma is established by using a higher peak power and a higher duty cycle during the ignition stage; the average power, pulse duty cycle, or pulse frequency is gradually reduced during the de-energizing stage; and a transparent conductive film is deposited by using a lower average power and a lower ion arrival energy during the deposition stage.

[0079] Optionally, the baffle can be kept closed during the ignition and de-energization phases, and opened only during the deposition phase. Alternatively, the substrate bias can be set to 0 V, floating, or a weak negative bias during the deposition phase to avoid high-energy ion bombardment of the sensitive layer.

[0080] Example 6: Plasma-assisted evaporation or ion beam-assisted deposition

[0081] In plasma-assisted evaporation equipment, O2 or other reactive gases can be activated first with a high plasma source power, and then the plasma source power or the activation intensity of the reactive gases can be gradually reduced before depositing transparent conductive oxides under low activation intensity conditions.

[0082] In ion beam assisted deposition equipment, a stable ion beam can be established first with a high ion beam energy, and then the ion beam energy and ion beam current density can be gradually reduced to reduce the energy of the auxiliary ions reaching the substrate, and then a transparent conductive film can be deposited.

[0083] This embodiment further illustrates that the present invention protects a cross-device plasma energy management strategy, rather than a specific device model or a specific deposition source.

[0084] Example 7: Double / Multilayer Transparent Conductive Film

[0085] like Figure 4 As shown, a first sublayer is first deposited on the electron transport layer. The first sublayer is formed using the lowest possible deposition bombardment intensity and has a thickness of 0.2 nm to 20 nm, preferably 0.5 nm to 10 nm. The first sublayer can be InO. x SnO x TiO x , ZnO, IZO, ITO or IWO.

[0086] After the first sublayer is formed, a second or more sublayers are deposited without damaging the first sublayer. The thickness of the second sublayer is from 5 nm to 500 nm, preferably from 20 nm to 100 nm. The second sublayer may have a higher carrier concentration or a lower sheet resistance.

[0087] Oxygen content gradients, doping concentration gradients, carrier concentration gradients, or work function gradients can form between multiple sublayers. For example, the side closer to the electron layer has a higher oxygen content and a lower defect density, while the side farther from the electron layer has a lower sheet resistance.

[0088] This structure can improve the conductivity of the transparent conductive film while ensuring low interface damage and low recombination.

[0089] Example 8: Few-layer perovskite / silicon tandem solar cell

[0090] like Figure 5 The diagram illustrates the fabrication of a crystalline silicon substrate solar cell. The crystalline silicon substrate solar cell can be a heterocrystalline silicon solar cell, a TOPCon solar cell, a PERC solar cell, an IBC solar cell, or other crystalline silicon solar cells.

[0091] A hole transport layer is formed on the intermediate connecting layer. The hole transport layer can be a self-assembled monolayer, NiO, etc. x CuO x CuI, PTAA, PEDOT:PSS, Spiro-OMeTAD or combinations thereof.

[0092] A perovskite absorber layer is formed on the hole transport layer. The perovskite absorber layer can be an ABX3 type organic-inorganic hybrid perovskite, an all-inorganic perovskite, a mixed cation perovskite, a mixed halogen perovskite, or a wide-bandgap perovskite. The thickness of the perovskite layer can be from 300 nm to 1000 nm.

[0093] A surface passivation layer is formed on the perovskite absorber layer. The surface passivation layer may include LiF, EDAI, PEAI, F-PEAI, two-dimensional perovskite, organic ammonium salt, halide salt, or fullerene derivative.

[0094] C is formed on the surface passivation layer 60 Electron transport layer. C 60 The electron transport layer thickness can be from 5 nm to 20 nm. Then, using any of the methods in Examples 1 to 7, in C... 60 InO is formed directly on the electron transport layer x A transparent conductive film is formed. Finally, Ag, Cu, Al, Ni, Cr, Sn, low-temperature silver paste, or copper electroplated grid lines are formed, and MgF2 and SiN can also be formed. x Al2O3, polymer or glass encapsulation layer.

[0095] In this structure, such as Figure 6 As shown, C 60 Electron transport layer and InO x ALD-SnO is not placed between the transparent conductive films. x Buffer layer. Due to C 60 The thickness can be reduced, and parasitic absorption is decreased; due to InO x The transparent conductive film has a good electron extraction contact with C60, which can improve the device fill factor and short-circuit current.

[0096] Example 9: Single-junction perovskite solar cells and semi-transparent perovskite solar cells

[0097] A hole transport layer, a perovskite absorber layer, and an electron transport layer are sequentially formed on a transparent conductive substrate. Using the method of this invention, a top transparent conductive film is formed on the electron transport layer to obtain a single-junction perovskite solar cell.

[0098] When both the upper and lower electrodes are transparent conductive films, a semi-transparent perovskite solar cell can be obtained. Because the method of this invention operates at low temperature and with low damage, it is particularly suitable for flexible substrates, polymer substrates, and heat-sensitive semi-transparent devices.

[0099] Example 10: Low-damage deposition of a transparent electrode on the top of a light-emitting device

[0100] A semi-finished light-emitting device is provided. The semi-finished product may include a transparent or opaque first electrode, a hole injection layer, a hole transport layer, a perovskite light-emitting layer, an organic light-emitting layer or a quantum dot light-emitting layer, and an electron transport layer or an electron injection layer. The light-emitting layer and its adjacent transport / injection layer are thermally sensitive and plasma-sensitive functional layers.

[0101] The semi-finished product is placed in a reactive plasma deposition apparatus, a magnetron sputtering apparatus, or a remote plasma deposition apparatus. With the baffle closed or the substrate avoiding the main deposition flux, a stable plasma is established using high discharge parameters. Subsequently, the discharge current, target power density, pulse duty cycle, gas flow rate, or substrate bias are gradually reduced to bring the plasma into a low thermal load and low bombardment energy state. The baffle is then opened, and ITO, IZO, or InO are formed on the electron transport layer, electron injection layer, hole transport layer, or hole injection layer. x IWO or other transparent conductive films.

[0102] In this embodiment, the transparent conductive film can serve as the top transparent electrode, semi-transparent electrode, or light-emitting side electrode of the light-emitting device. Compared with conventional high-power direct sputtering, this method can reduce the attenuation of photoluminescence or electroluminescence in the light-emitting layer, reduce interface defects and charge injection degradation, and is suitable for perovskite light-emitting diodes, organic light-emitting diodes, quantum dot light-emitting diodes, transparent light-emitting devices, and flexible light-emitting devices.

[0103] Example 11: Fabrication of Large-Area Photovoltaic Devices

[0104] Semi-finished photovoltaic devices with dimensions of 166 mm × 166 mm, 182 mm × 182 mm, 210 mm × 210 mm, or larger are placed in large-area reactive plasma deposition or magnetron sputtering equipment. Large-area uniform deposition is achieved through multi-zone gas supply, multi-zone power control, multi-cathode arrangement, moving substrate transport, or rotating substrate support stage.

[0105] Each deposition zone performs an initiation phase, a phased de-energization phase, and a low-damage deposition phase. For continuous equipment, initiation and de-energization stabilization can be completed in the front stage, and deposition can be performed in the back stage; alternatively, multiple cathodes can be in different discharge stages, so that the substrate is only exposed to the low-damage deposition zone.

[0106] For large-area deposition, it is preferable to use multi-parameter feedback control of substrate temperature, deposition rate, thin film sheet resistance, plasma luminescence intensity and target voltage to reduce the non-uniformity of thickness and electrical properties.

[0107] Comparative Example 1: Direct deposition of transparent conductive film by conventional high-power sputtering

[0108] Will contain perovskite / C 60 The stacked substrates to be deposited are directly exposed to the conventional magnetron sputtering main deposition flux, and a transparent conductive film is deposited at a fixed high power density. While this method achieves a lower sheet resistance, the high-energy particles in the initiation and deposition stages can directly affect the C2O2. 60 The interface with the perovskite can easily cause interface damage, reduced photoluminescence, increased nonradiative recombination, and decreased device fill factor.

[0109] Comparative Example 2: Direct Low-Power Ignition Deposition of Transparent Conductive Film

[0110] Magnetron sputtering or reactive plasma deposition equipment can be directly set to low power or low current for ignition. While this method helps reduce damage, it may lead to problems such as ignition failure, unstable discharge, low deposition rate, insufficient film conductivity, and poor batch-to-batch repeatability.

[0111] Comparative Example 3: Setting ALD-SnO x Depositing a transparent conductive film after the buffer layer

[0112] In C 60 ALD-SnO is formed between the layer and the transparent conductive film. x After the buffer layer, a transparent conductive film is deposited. This method can mitigate plasma damage, but it increases equipment, process steps and processing time, and may introduce additional parasitic absorption and interfacial resistance.

[0113] The difference between the embodiments of the present invention and the comparative examples is as follows:

[0114] Compared with Comparative Example 1, the present invention does not subject the sensitive layer to the ignition stage and the high-power deposition stage, but instead ignites it in a shielded or non-main deposition state and performs deposition after staged energy reduction.

[0115] Compared with Comparative Example 2, this invention does not directly initiate low-power ignition, but first uses higher parameters to ensure reliable plasma establishment, and then gradually reduces to a low-damage deposition window, thus taking into account both discharge stability and low damage.

[0116] Compared with Comparative Example 3, the present invention can reduce or eliminate ALD-SnO x The buffer layer reduces process complexity and parasitic absorption, while maintaining interface integrity through low-damage deposition.

[0117] This invention can be used in perovskite / silicon tandem solar cells, single-junction perovskite solar cells, semi-transparent perovskite solar cells, flexible perovskite solar cells, perovskite / perovskite tandem solar cells, perovskite / CIGS tandem solar cells, photovoltaic modules and other optoelectronic devices.

[0118] This invention can reduce the need for ALD buffer layers and other protective layers, thereby reducing material consumption, equipment occupancy, and process cycle time, making it suitable for large-area industrial continuous coating equipment.

[0119] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for low-damage deposition of a transparent conductive film, characterized in that, Includes the following steps: A, providing a substrate to be deposited, wherein the surface of the substrate to be deposited includes a plasma-sensitive functional layer; B. Introduce working gas and optional reactive gas into a vacuum chamber, and establish a stable plasma with a first discharge parameter when the substrate to be deposited is not exposed to the main deposition flux or is only exposed to a state below the film formation flux. The first discharge parameter is higher than the ignition threshold of the plasma. C. After the stable plasma is established, the discharge parameter is reduced from the first discharge parameter to the second discharge parameter through at least two consecutive or stepwise steps. The second discharge parameter is higher than the plasma extinguishing threshold and lower than the first discharge parameter. The reduction of discharge parameters includes reducing at least one of the following: discharge current, discharge power, target power density, target voltage, ion beam energy, pulse duty cycle, working gas flow rate, reactive gas flow rate, substrate bias, and plasma source power. D, Under the second discharge parameters, a transparent conductive material is deposited onto the surface of the plasma-sensitive functional layer of the substrate to be plated, forming a transparent conductive film; The plasma bombardment intensity experienced by the plasma-sensitive functional layer during the formation of the transparent conductive film is lower than that in step B.

2. The method according to claim 1, characterized in that, The substrate to be deposited in step B is not exposed to the main deposition flux or is only exposed to a state below the film formation flux, which is achieved by at least one of the following methods: closing the deposition baffle, setting a substrate shielding element, deviating the substrate from the main deposition direction, increasing the target-substrate distance, reducing the substrate bias voltage, rotating the substrate to a non-deposition area, or putting the deposition source in a pre-sputtering / pre-evaporation state.

3. The method according to claim 1, characterized in that, Step C includes at least two de-energizing stages; each de-energizing stage lasts from 0.5 seconds to 30 minutes; between two adjacent de-energizing stages, the discharge current, discharge power, or target power density is reduced by 1% to 80%.

4. The method according to claim 1, characterized in that, The transparent conductive film includes a first sublayer close to the plasma-sensitive functional layer and a second sublayer located on the first sublayer; the deposition bombardment intensity of the first sublayer is lower than that of the second sublayer, the thickness of the first sublayer is 0.2 nm to 20 nm, and the thickness of the second sublayer is 5 nm to 500 nm. The first sub-layer is InO x SnO x TiO x Any one of ZnO, IZO, ITO, and IWO; the second sublayer is InO. x Any one of IZO, ITO, IWO, AZO, and GZO.

5. The method according to claim 1, characterized in that, The plasma-sensitive functional layer includes at least one of the following: a perovskite absorption layer, a fullerene electron transport layer, a fullerene derivative electron transport layer, an organic electron transport layer, an organic hole transport layer, a self-assembled monolayer, a two-dimensional perovskite layer, a perovskite surface passivation layer, a quantum dot layer, an organic semiconductor layer, a chalcogenide semiconductor layer, and a two-dimensional semiconductor layer. The plasma-sensitive functional layer includes an electron transport layer, which contains C 60 C 70 PCBM, BCP, LiF, SnO x TiO x ZnO or a combination thereof, wherein the transparent conductive film is directly deposited on the electron transport layer; and no atomic layer SnO is deposited between the plasma-sensitive functional layer and the transparent conductive film. x The buffer layer may be omitted, or an inorganic buffer layer with a thickness greater than 3 nm may not be provided, or a metal oxide buffer layer formed by atomic layer deposition may not be provided.

6. The method according to claim 1, characterized in that, Step C and / or step D employ feedback control, and the feedback signals include at least one of the following: plasma luminescence intensity, discharge impedance, target voltage, target current, discharge current, cavity pressure, substrate temperature, deposition rate, thin film sheet resistance, optical transmittance, photoluminescence intensity, and mass spectrometry signal.

7. The method according to claim 1, characterized in that, The method is implemented using a reactive plasma deposition apparatus; in step B, a stable plasma is established with a first discharge current; in step C, the discharge current is reduced to a second discharge current in stages; and in step D, the transparent conductive film is deposited under the second discharge current. Step C involves first reducing the discharge current from 30 A to 40 A to 20 A to 30 A and maintaining it for 10 to 300 seconds; then reducing it to 15 A to 25 A and maintaining it for 10 to 300 seconds; then reducing it to 10 A to 20 A and maintaining it for 30 to 900 seconds; and then proceeding to step D.

8. The method according to claim 1, characterized in that, The method is implemented using a magnetron sputtering device, which is a DC magnetron sputtering device, a radio frequency magnetron sputtering device, a medium frequency magnetron sputtering device, a pulsed DC magnetron sputtering device, a reactive magnetron sputtering device, a high power pulsed magnetron sputtering device, or a combination thereof; in step B, the device is ignited at a first target power density; in step C, the target power density, target voltage, pulse duty cycle, or substrate bias voltage is reduced in stages to a second target power density; and in step D, the transparent conductive film is deposited at the second target power density. The first target power density is 0.5 W / cm². 2 Up to 20W / cm 2 The second target power density is 0.01 W / cm². 2 Up to 5W / cm 2 .

9. The method according to claim 1, characterized in that, The method is implemented using any one of plasma-assisted evaporation, ion beam-assisted deposition, hollow cathode discharge deposition, electron beam evaporation combined with plasma activation, or remote plasma deposition; in step C, low-damage deposition is achieved by reducing the plasma source power, ion beam energy, ion beam current density, reactive gas activation intensity, or substrate bias.

10. A photovoltaic device, characterized in that, The photovoltaic device includes a light-absorbing layer, a carrier transport layer located on one side of the light-absorbing layer, and a transparent conductive film located on the carrier transport layer; the carrier transport layer is in direct contact with the transparent conductive film.

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