TCO film and preparation method thereof

Abstract

The invention belongs to the related field of photoelectric devices, and particularly discloses a TCO thin film and a preparation method thereof.The TCO thin film comprises a substrate, a first silicon oxide layer, a first indium oxide layer, a transition layer, a second indium oxide layer and a second silicon oxide layer which are sequentially arranged from bottom to top; the transition layer comprises an indium oxide layer, a silicon oxide layer and an indium oxide layer which are sequentially arranged from bottom to top. By controlling the distribution of the indium oxide layer, the silicon oxide layer and the transition layer, the silicon oxide layer with low refractive index and the indium oxide layer with high refractive index are alternately arranged, Fresnel reflection is reduced through gradual change of interface refractive index, the front electrode is suitable for the photovoltaic cell, and the photoelectric conversion efficiency of the photovoltaic cell is improved.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic devices and relates to a transparent conductive film, specifically a TCO film and its preparation method. Background Technology

[0002] Transparent conductive oxide (TCO) films are widely used in optoelectronic devices such as flat panel displays, solar cells, and touch screens due to their excellent conductivity and high transmittance in the visible light range. With the increasing performance requirements of optoelectronic devices, higher demands are being placed on the optoelectronic performance of TCO films. However, while commonly used single TCO films possess transparent and conductive properties, significant abrupt changes in refractive index between indium oxide (1.9–2.0) and air (approximately 1) and the battery substrate (such as silicon substrate with a refractive index of approximately 3.5) cause Fresnel reflection (the loss of light due to reflection at interfaces with different refractive indices). This results in the reflection and loss of some visible light (350–750 nm, the main absorption band of photovoltaic cells), which cannot participate in energy conversion and affects the electrochemical conversion efficiency of photovoltaic cells. Summary of the Invention

[0003] In view of the defects and deficiencies of the existing technology, the present invention provides a TCO thin film in the first aspect; and a method for preparing a TCO thin film in the second aspect.

[0004] In a first aspect, the present invention provides a TCO thin film comprising, from bottom to top, a substrate, a first silicon oxide layer, a first indium oxide layer, a transition layer, a second indium oxide layer, and a second silicon oxide layer; wherein the transition layer comprises, from bottom to top, an indium oxide layer, a silicon oxide layer, and an indium oxide layer.

[0005] Preferably, the thickness of each indium oxide layer in the transition layer is independently 0.75~1.5nm, the thickness of each silicon oxide layer in the transition layer is 0.5~1nm, and the total thickness of the transition layer is 2~5nm.

[0006] Preferably, the substrate is any one of glass, quartz, or plastic, and the thickness of the substrate is 500~700μm.

[0007] Preferably, barium is doped in the first silicon oxide layer, the second silicon oxide layer, and the silicon oxide layer in the transition layer, and the amount of barium doping is 0.15~0.25wt%.

[0008] Preferably, the first indium oxide layer, the second indium oxide layer, and the indium oxide layer in the transition layer are all doped with tin, and the amount of tin doping is 10~11wt%.

[0009] Preferably, the thickness of the first silicon oxide layer and the second silicon oxide layer are each independently 15~30nm.

[0010] Preferably, the thickness of the first indium oxide layer and the second indium oxide layer is independently 25~35nm.

[0011] Preferably, the resistance of the first silicon oxide layer and the second silicon oxide layer is 1×10⁻⁶. 5 ~5×10 6 Ω / sq, carrier mobility 1×10 -3 ~1×10 -2 cm 2 / (V·s); the resistivity of the first and second indium oxide layers is 28~45Ω / sq, and the carrier mobility is 15~40cm. 2 / (V·s); The resistivity of the indium oxide layer in the transition layer is 30~50Ω / sq, and the carrier mobility is 12~35cm. 2 / (V·s); The resistance of the silicon oxide layer in the transition layer is 8×10⁻⁶. 4 ~3×10 6 Ω / sq, carrier mobility 5×10 -4 ~8×10 -3 cm 2 / (V·s).

[0012] Thirdly, the present invention provides a method for preparing a TCO thin film, comprising: Step 1: Deposit a first silicon oxide layer on the substrate surface using a magnetron sputtering process; Step 2: Deposit a first indium oxide layer on the surface of the first silicon oxide layer using a magnetron sputtering process; Step 3: A transition layer is deposited on the surface of the first indium oxide layer using a magnetron sputtering process. During the deposition of the transition layer, the indium oxide layer, the silicon oxide layer, and the indium oxide layer are deposited sequentially from bottom to top. Step 4: Repeat steps 1-2 to deposit the second indium oxide layer and the second silicon oxide layer in sequence.

[0013] Preferably, the substrate is pretreated before step 1 by ultrasonically cleaning it in acetone, anhydrous ethanol and deionized water for 20-40 minutes in sequence.

[0014] Preferably, in step 1, when depositing the first silicon oxide layer, the deposition atmosphere is a mixture of oxygen and argon, the argon flow rate is 300~400 sccm, the oxygen flow rate is 0~100 sccm, the deposition temperature is 25~100℃, the deposition pressure is 0.5~0.6 Pa, the radio frequency power is 5.5~6 kW, the radio frequency is 15~25 kHz, and the deposition rate is 1.0~1.5 nm / s.

[0015] Preferably, in step 2, when depositing the first indium oxide layer, the deposition atmosphere is a mixture of oxygen and argon, with oxygen accounting for 1 vol% to 2.5 vol% and the remainder being argon. The deposition temperature is 25 to 75°C, the deposition pressure is 0.5 to 0.65 Pa, the radio frequency power is 5.5 to 6.5 kW, and the deposition rate is 4.29 to 5.25 nm / s.

[0016] Preferably, in step 3, when depositing the indium oxide layer, the deposition atmosphere is a mixture of oxygen and argon, with oxygen accounting for 0.5 vol% to 0.8 vol% and the remainder being argon. The deposition temperature is 25 to 75°C, the deposition pressure is 0.5 to 0.6 Pa, the radio frequency power is 5.5 to 6.5 kW, and the deposition rate is 4.5 to 4.85 nm / s.

[0017] Preferably, in step 3, when depositing the silicon oxide layer, the deposition atmosphere is a mixture of oxygen and argon, the argon flow rate is 300~400 sccm, the oxygen flow rate is 0~100 sccm, the deposition temperature is 25~100℃, the deposition pressure is 0.55~0.65 Pa, the radio frequency power is 5.5~6.5 kW, the radio frequency is 15~25 kHz, and the deposition rate is 1~2 nm / s.

[0018] Further preferred, in step 3, when depositing the silicon oxide layer, the silicon oxide layer is deposited in 2 or 4 stages.

[0019] Preferably, in step 4, the process parameters for depositing the second indium oxide layer are the same as those for depositing the first indium oxide layer in step 1; the process parameters for depositing the second silicon oxide layer are the same as those for depositing the first silicon oxide layer in step 1.

[0020] Preferably, step 4 is followed by an annealing process, in which the thin film material obtained in step 3 is annealed at 200-230°C for 50-70 minutes in an air atmosphere.

[0021] Compared with the prior art, one or more technical solutions provided by the present invention have at least one of the following beneficial effects: (1) By controlling the distribution of indium oxide layer, silicon oxide layer and transition layer, the low refractive index silicon oxide layer and the high refractive index indium oxide layer are arranged alternately. Fresnel reflection is reduced by the gradual change of interface refractive index, which is suitable for the front electrode of photovoltaic cell and improves the photoelectric conversion efficiency of photovoltaic cell.

[0022] (2) The indium oxide layer has good optical transmittance and excellent electrical conductivity. The silicon oxide layer is a functional layer that resists mechanical stress and chemical corrosion and extends the service life of the film. The transition layer is composed of alternating indium oxide and silicon oxide layers, which helps to regulate charge transport and distribution, reduce charge accumulation at the interface, and thus improve the electrical performance and stability of the overall structure. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the film structure of the TCO thin film prepared in Example 1; Figure 2 This is a schematic diagram of the membrane structure of the transition layer obtained in Example 1. Detailed Implementation

[0024] The present invention provides the following specific technical solutions.

[0025] In a first aspect, the present invention provides a TCO thin film comprising, from bottom to top, a substrate, a first silicon oxide layer, a first indium oxide layer, a transition layer, a second indium oxide layer, and a second silicon oxide layer; wherein the transition layer comprises, from bottom to top, an indium oxide layer, a silicon oxide layer, and an indium oxide layer.

[0026] Through research, the inventors discovered that optimizing the layered structure of the TCO thin film, the distribution of indium oxide, silicon oxide, and transition layers, and the alternating arrangement of low-refractive-index silicon oxide and high-refractive-index indium oxide layers, gradually transitions the refractive index difference between air, electrode, and battery substrate through refractive gradient matching. This significantly reduces Fresnel reflection loss, allowing more visible light to penetrate the front electrode and enter the light absorption layer of the battery, directly increasing the total light absorption and providing more energy for subsequent carrier excitation. Furthermore, photovoltaic cells need to withstand environmental stresses such as sunlight, humidity, and temperature changes outdoors for extended periods. The stability design of this structure can extend battery life and indirectly ensure long-term photoelectric conversion efficiency.

[0027] Preferably, the substrate is any one of glass, quartz, or plastic, and the thickness of the substrate is 500~700μm.

[0028] Preferably, barium is doped in the first silicon oxide layer, the second silicon oxide layer, and the silicon oxide layer in the transition layer, and the amount of barium doping is 0.15~0.25wt%.

[0029] Through research, the inventors discovered that doping the silicon oxide layer with barium replaces some of the silicon ions or fills the lattice interstices, reducing the density of the silicon oxide layer and further lowering its refractive index. This allows for a more precise match between the air and indium oxide layers, resulting in a smoother transition of refractive index between air, silicon oxide, and indium oxide, further reducing Fresnel reflection caused by abrupt changes in refractive index. Furthermore, barium doping improves the film quality of the silicon oxide layer, making its interface with the upper and lower indium oxide layers smoother, reducing interface roughness, and avoiding light scattering losses caused by interface unevenness.

[0030] Preferably, the thickness of the first silicon oxide layer and the second silicon oxide layer are each independently 15~30nm.

[0031] Preferably, the first indium oxide layer, the second indium oxide layer, and the indium oxide layer in the transition layer are all doped with tin, and the amount of tin doping is 10~11wt%.

[0032] Through research, the inventors discovered that doping indium oxide layers with tin can significantly improve its conductivity and maintain high refractive index, allowing the indium oxide layer to serve as a high refractive index unit. This creates a clear refractive index difference with the low refractive index silicon oxide layer doped with barium, providing a basis for the alternating stacked high and low refractive index periodic structure. The thin film interference effect cancels out interface reflection, further reducing reflection loss in the visible light band.

[0033] Preferably, the thickness of the first indium oxide layer and the second indium oxide layer is independently 25~35nm.

[0034] Preferably, the thickness of each indium oxide layer in the transition layer is independently 0.75~1.5nm, the thickness of each silicon oxide layer in the transition layer is 0.5~1nm, and the total thickness of the transition layer is 2~5nm.

[0035] Preferably, the resistance of the first silicon oxide layer and the second silicon oxide layer is 1×10⁻⁶. 5 ~5×10 6 Ω / sq, carrier mobility 1×10 -3 ~1×10 -2 cm 2 / (V·s); the resistivity of the first and second indium oxide layers is 28~45Ω / sq, and the carrier mobility is 15~40cm. 2 / (V·s); The resistivity of the indium oxide layer in the transition layer is 30~50Ω / sq, and the carrier mobility is 12~35cm. 2 / (V·s); The resistance of the silicon oxide layer in the transition layer is 8×10⁻⁶. 4 ~3×10 6 Ω / sq, carrier mobility 5×10 -4 ~8×10 -3 cm 2 / (V·s).

[0036] Thirdly, the present invention provides a method for preparing a TCO thin film, comprising: Step 1: Deposit a first silicon oxide layer on the substrate surface using a magnetron sputtering process; Step 2: Deposit a first indium oxide layer on the surface of the first silicon oxide layer using a magnetron sputtering process; Step 3: A transition layer is deposited on the surface of the first indium oxide layer using a magnetron sputtering process. During the deposition of the transition layer, the indium oxide layer, the silicon oxide layer, and the indium oxide layer are deposited sequentially from bottom to top. Step 4: A second indium oxide layer and a second silicon oxide layer are sequentially deposited on the surface of the transition layer using a magnetron sputtering process.

[0037] Preferably, the substrate is pretreated before step 1 by ultrasonically cleaning it in acetone, anhydrous ethanol and deionized water for 20-40 minutes in sequence.

[0038] Preferably, in steps 1 and 4, when depositing the first silicon oxide layer and the second silicon oxide layer, the deposition atmosphere is a mixture of oxygen and argon, the argon flow rate is 300~400 sccm, the oxygen flow rate is 0~100 sccm, the deposition temperature is 25~100℃, the deposition pressure is 0.5~0.6 Pa, the radio frequency power is 5.5~6 kW, the radio frequency is 15~25 kHz, and the deposition rate is 1.0~1.5 nm / s.

[0039] Through research, the inventors discovered that by controlling the flow rates of argon and oxygen during silicon oxide deposition, the oxygen content in the deposition atmosphere can be controlled, thereby controlling the resistance and carrier concentration of the silicon oxide layer. Through the multilayer structure of the TCO thin film, long-term photoelectric conversion efficiency can be guaranteed.

[0040] Preferably, in steps 2 and 4, when depositing the first indium oxide layer and the second indium oxide layer, the deposition atmosphere is a mixture of oxygen and argon, with oxygen accounting for 1 vol% to 2.5 vol% and the remainder being argon. The deposition temperature is 25 to 75°C, the deposition pressure is 0.5 to 0.65 Pa, the radio frequency power is 5.5 to 6.5 kW, and the deposition rate is 4.29 to 5.25 nm / s.

[0041] Preferably, in step 3, when depositing the indium oxide layer, the deposition atmosphere is a mixture of oxygen and argon, with oxygen accounting for 0.5 vol% to 0.8 vol% and the remainder being argon. The deposition temperature is 25 to 75°C, the deposition pressure is 0.5 to 0.6 Pa, the radio frequency power is 5.5 to 6.5 kW, and the deposition rate is 4.5 to 4.85 nm / s.

[0042] Preferably, in step 3, when depositing the silicon oxide layer, the deposition atmosphere is a mixture of oxygen and argon, the argon flow rate is 300~400 sccm, the oxygen flow rate is 0~100 sccm, the deposition temperature is 25~100℃, the deposition pressure is 0.55~0.65 Pa, the radio frequency power is 5.5~6.5 kW, the radio frequency is 15~25 kHz, and the deposition rate is 1~2 nm / s.

[0043] Through research, the inventors discovered that by adjusting the coating parameters in the transition layer during coating, a suitable bandgap and dielectric constant can be formed. At the same time, the surface flatness and lattice matching can be optimized. Combined with the first indium oxide layer, the second indium oxide layer, the first silicon oxide layer, and the second silicon oxide layer, it helps to regulate charge transport and distribution, reduce charge accumulation at the interface, and thus improve the electrical performance and stability of the overall structure.

[0044] Further preferred, in step 3, when depositing the silicon oxide layer, the silicon oxide layer is deposited in 2 or 4 stages.

[0045] During film deposition, if a silicon oxide layer of a certain thickness is deposited in a single step, the resulting silicon oxide layer is prone to uneven thickness on both sides. The inventors discovered that depositing the silicon oxide layer in multiple stages can balance this unevenness and improve the overall uniformity of the silicon oxide layer. Depending on the thickness of the target silicon oxide layer, it is deposited in even-numbered stages, such as two or four stages. If the target silicon oxide layer is thicker, the number of deposition stages can be increased. To improve deposition efficiency, two-stage deposition ensures uniform silicon oxide thickness. Specifically, during silicon oxide deposition, deposition is first performed gradually along any straight line of the substrate until one deposition is completed. Then, a second deposition is performed in the opposite direction of that straight line, resulting in a silicon oxide layer of uniform thickness.

[0046] Preferably, in step 4, the process parameters for depositing the second indium oxide layer are the same as those for depositing the first indium oxide layer in step 1; the process parameters for depositing the second silicon oxide layer are the same as those for depositing the first silicon oxide layer in step 1.

[0047] Preferably, step 4 is followed by an annealing process, in which the thin film material obtained in step 3 is annealed at 200-230°C for 50-70 minutes in an air atmosphere.

[0048] To make the technical problems, technical solutions and technical advantages of the present invention clearer, a detailed description will be given below with reference to specific examples. However, the scope of protection of the present invention is not limited to the following specific embodiments.

[0049] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0050] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0051] Example 1: A TCO thin film, comprising the following steps: Step 1: The 100mm×100mm glass substrate with a thickness of 600μm was ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 30min in sequence, and then dried in a low temperature drying oven at 100℃ for 1 hour.

[0052] Step 2: Place the glass substrate in the sputtering chamber. The target material is silicon oxide (doped with 0.2 wt% barium). Then turn on the magnetron sputtering equipment. The chamber pressure is 0.6 Pa, the RF power is 6 kW, the RF frequency is 20 kHz, the substrate temperature is 25 °C, the argon flow rate is 320 sccm, the oxygen flow rate is 80 sccm, and the deposition rate is 1.275 nm / s. The thickness of the first silicon oxide layer is 20 nm.

[0053] Step 3: Deposit a first indium oxide layer on the surface of the silicon oxide layer. The target material is indium oxide (doped with 10 wt% tin). The oxygen content in the deposition atmosphere is 1 vol%, with the balance being argon. The deposition temperature is 25℃, the deposition pressure is 0.55 Pa, the radio frequency power is 5.5 kW, the deposition rate is 5.25 nm / s, and the thickness of the first indium oxide layer is 30 nm.

[0054] Step 4: During the deposition of the transition layer, indium oxide, silicon oxide and indium oxide layers are deposited alternately. The transition layer consists of an indium oxide layer (thickness of 1.25 nm), a silicon oxide layer (thickness of 0.5 nm) and an indium oxide layer (thickness of 1.25 nm) from bottom to top.

[0055] During the deposition of indium oxide, the oxygen content in the deposition atmosphere was 0.75 vol%, with the remainder being argon. The deposition temperature was 25 °C, the deposition pressure was 0.55 Pa, the radio frequency power was 6 kW, and the deposition rate was 4.75 nm / s.

[0056] During the deposition of the silicon oxide layer, the argon flow rate was 320 sccm, the oxygen flow rate was 80 sccm, the deposition temperature was 25℃, the deposition pressure was 0.6 Pa, the RF power was 6 kW, the RF frequency was 20 kHz, and the deposition rate was 1.275 nm / s. The 0.5 nm thick silicon oxide layer was deposited in two stages.

[0057] Step 5: Repeat steps 2 and 3 in sequence (the parameters for depositing the indium oxide layer and the silicon oxide layer are the same as in steps 3 and 2), deposit an indium oxide layer with a thickness of 30 nm on the surface of the transition layer, and then deposit a silicon oxide layer with a thickness of 20 nm on the surface of the indium oxide layer.

[0058] Step 6: Anneal the film material obtained in step 5 at 230°C for 60 minutes.

[0059] Example 2: A TCO thin film, comprising the following steps: Step 1: The 100mm×100mm glass substrate with a thickness of 600μm was ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 30min in sequence, and then dried in a low temperature drying oven at 100℃ for 1 hour.

[0060] Step 2: Place the glass substrate in the sputtering chamber. The target material is silicon oxide (doped with 0.15wt% barium). Then turn on the magnetron sputtering equipment. The chamber pressure is 0.5Pa, the RF power is 5.5kW, the RF frequency is 15kHz, the substrate temperature is 25℃, the argon flow rate is 300sccm, the oxygen flow rate is 100sccm, and the deposition rate is 1.05nm / s. The thickness of the first silicon oxide layer is 15nm.

[0061] Step 3: Deposit a first indium oxide layer on the surface of the silicon oxide layer. The target material is indium oxide (doped with 10.5 wt% tin). The oxygen content in the deposition atmosphere is 2.5 vol%, with the balance being argon. The deposition temperature is 25℃, the deposition pressure is 0.5 Pa, the RF power is 4 kW, the deposition rate is 4.51 nm / s, and the thickness of the obtained indium oxide layer is 25 nm.

[0062] Step 4: Deposit a transition layer, alternating between indium oxide, silicon oxide, and indium oxide layers. The transition layer consists of, from bottom to top, an indium oxide layer (0.75 nm thick), a silicon oxide layer (0.5 nm thick), and an indium oxide layer (0.75 nm thick). During indium oxide deposition, the oxygen content in the deposition atmosphere is 0.5 vol%, with the balance being argon. The deposition temperature is 25 °C, the deposition pressure is 0.55 Pa, the RF power is 6 kW, and the deposition rate is 4.51 nm / s.

[0063] During the deposition of the silicon oxide layer, the argon flow rate was 300 sccm, the oxygen flow rate was 100 sccm, the deposition temperature was 25℃, the deposition pressure was 0.6 Pa, the RF power was 5.5 kW, the RF frequency was 15 kHz, and the deposition rate was 1.05 nm / s. The 0.5 nm thick silicon oxide layer was deposited in two stages.

[0064] Step 5: Repeat steps 3 and 2 in sequence (the parameters for depositing the indium oxide layer and the silicon oxide layer are the same as in steps 3 and 2), deposit an indium oxide layer with a thickness of 25 nm on the surface of the transition layer, and then deposit a silicon oxide layer with a thickness of 15 nm on the surface of the indium oxide layer.

[0065] Step 6: Anneal the film material obtained in step 5 at 200°C for 50 minutes.

[0066] Example 3: A TCO thin film, comprising the following steps: Step 1: The 100mm×100mm glass substrate with a thickness of 600μm was ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 30min in sequence, and then dried in a low temperature drying oven at 100℃ for 1 hour.

[0067] Step 2: Place the glass substrate in the sputtering chamber. The target material is silicon oxide (doped with 0.21 wt% barium). Then turn on the magnetron sputtering equipment. The chamber pressure is 0.6 Pa, the RF power is 5.8 kW, the RF frequency is 20 kHz, the substrate temperature is 25 °C, the argon flow rate is 395 sccm, the oxygen flow rate is 5 sccm, and the deposition rate is 1.5 nm / s. The thickness of the first silicon oxide layer is 30 nm.

[0068] Step 3: Deposit a first indium oxide layer on the surface of the silicon oxide layer. The target material is indium oxide (doped with 10 wt% tin). The oxygen content in the deposition atmosphere is 1.5 vol%, with the balance being argon. The deposition temperature is 25℃, the deposition pressure is 0.65 Pa, the radio frequency power is 5.5 kW, the deposition rate is 4.5 nm / s, and the thickness of the first indium oxide layer is 35 nm.

[0069] Step 4: Deposit a transition layer by alternately depositing an indium oxide layer, a silicon oxide layer, and an indium oxide layer. The transition layer consists of an indium oxide layer (1.5 nm thick), a silicon oxide layer (1 nm thick), and an indium oxide layer (1.5 nm thick) from bottom to top.

[0070] During the deposition of indium oxide, the oxygen content in the deposition atmosphere was 0.6 vol%, with the balance being argon. The deposition temperature was 25 °C, the deposition pressure was 0.55 Pa, the radio frequency power was 6 kW, and the deposition rate was 5.25 nm / s. During the deposition of the silicon oxide layer, the argon flow rate was 395 sccm, the oxygen flow rate was 5 sccm, the deposition temperature was 25℃, the deposition pressure was 0.6 Pa, the RF power was 5.8 kW, the RF frequency was 20 kHz, and the deposition rate was 4.7 nm / s.

[0071] Step 5: Repeat steps 3 and 2 in sequence (the parameters for depositing the indium oxide layer and the silicon oxide layer are the same as in steps 3 and 2), deposit an indium oxide layer with a thickness of 35 nm on the surface of the transition layer, and then deposit a silicon oxide layer with a thickness of 30 nm on the surface of the indium oxide layer.

[0072] Step 6: Anneal the film material obtained in step 5 at 220°C for 60 minutes.

[0073] Comparative Example 1: A TCO thin film, comprising the following steps: Step 1: The 100mm×100mm glass substrate with a thickness of 600μm was ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 30min in sequence, and then dried in a low temperature drying oven at 100℃ for 1 hour.

[0074] Step 2: Place the glass substrate in the sputtering chamber. The target material is silicon oxide (doped with 0.2 wt% barium). Then turn on the magnetron sputtering equipment. The chamber pressure is 0.6 Pa, the RF power is 6 kW, the RF frequency is 20 kHz, the substrate temperature is 25 °C, the argon flow rate is 320 sccm, the oxygen flow rate is 80 sccm, and the deposition rate is 1.275 nm / s. The thickness of the first silicon oxide layer is 20 nm.

[0075] Step 3: Indium oxide layer is deposited on the surface of silicon oxide layer. The target material is indium oxide (doped with 10 wt% tin). The oxygen content in the deposition atmosphere is 1 vol%, and the balance is argon. The deposition temperature is 25℃, the pressure is 0.55 Pa, the power is 5 kW, the deposition rate is 5.25 nm / s, and the thickness of the obtained indium oxide layer is 30 nm.

[0076] Step 4: Repeat steps 3 and 2 to deposit an indium oxide layer with a thickness of 30 nm on the surface of the transition layer, and then deposit a silicon oxide layer with a thickness of 10 nm on the surface of the indium oxide layer.

[0077] Step 5: Anneal the film material obtained in step 4 at 230°C for 60 minutes.

[0078] Comparative Example 2: A TCO thin film, comprising the following steps: Step 1: The 100mm×100mm glass substrate with a thickness of 600μm was ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 30min in sequence, and then dried in a low temperature drying oven at 100℃ for 1 hour.

[0079] Step 2: Place the glass substrate in the sputtering chamber. The target material is silicon oxide (doped with 0.2 wt% barium). Then turn on the magnetron sputtering equipment. The chamber pressure is 0.6 Pa, the RF power is 6 kW, the RF frequency is 20 kHz, the substrate temperature is 25 °C, the argon flow rate is 320 sccm, the oxygen flow rate is 80 sccm, and the deposition rate is 1.275 nm / s. The thickness of the first silicon oxide layer is 20 nm.

[0080] Step 3: Indium oxide layer is deposited on the surface of silicon oxide layer. The target material is indium oxide (doped with 10 wt% tin). The oxygen content in the deposition atmosphere is 1 vol%, and the balance is argon. The deposition temperature is 25℃, the pressure is 0.55 Pa, the power is 5 kW, the deposition rate is 5.25 nm / s, and the thickness of the obtained indium oxide layer is 30 nm.

[0081] Step 4: Anneal the film material obtained in Step 3 at 230°C for 60 minutes.

[0082] Comparative Example 3: A TCO thin film differs from Example 1 in that the silicon oxide and indium oxide targets used are not doped with other metal elements.

[0083] The performance tests of the TCO films prepared in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1.

[0084] Table 1 Performance data of TCO films prepared in Examples 1-3 and Comparative Examples 1-3 As shown in Table 1, the transmittance of Examples 1-3 ranges from 92.01% to 94.1%, while that of Comparative Examples 1-3 is only 88.45% to 90.1%. This proves that the TCO film provided by the present invention adopts an ultra-thin composite structure of "indium oxide-silicon oxide-indium oxide", which can optimize the refractive index matching degree of the upper and lower indium oxide and silicon oxide layers, reduce light reflection loss at the interface, and improve light transmission efficiency. In contrast, Comparative Example 1 has no transition layer and Comparative Example 2 has a simple double-layer structure with a large abrupt change in refractive index at the interface, resulting in high light scattering and reflection loss and low transmittance.

[0085] Example 2 exhibits the highest transmittance of 94.1% among all samples, attributed to its thinner silicon oxide layer and moderate oxygen content. The thin silicon oxide layer reduces light absorption, while the moderate oxygen atmosphere ensures uniform crystallization of the indium oxide layer, further reducing light scattering. Example 3 has a lower transmittance (92.01%) because its silicon oxide layer is 30 nm thick; an excessively thick silicon oxide layer increases light path loss. However, the transmittance of Example 3 is still higher than that of Comparative Examples 1 and 2, demonstrating the role of the transition layer in improving light transmittance in the technical solution provided by this invention.

[0086] Comparing Example 1 and Comparative Example 1, Comparative Example 1, a four-layer structure without a transition layer, suffers from increased light scattering and reflection losses due to abrupt changes in interface refractive index, resulting in a visible light transmittance of only 90.1% and a reflectance of 8.9%. In contrast, Example 1 optimizes film layer matching through an "indium oxide-silicon oxide-indium oxide" transition layer, achieving interference reduction and reflection, increasing transmittance to 93.5% and reducing reflectance to 5.8%, resulting in significantly superior optical performance. Regarding electrical performance, although the transition layer introduces slight interface scattering, Example 1 exhibits higher RF power from the deposited indium oxide layer, superior conductive layer crystal quality, and a final sheet resistance reduction from 50.22 Ω / sq to 35.1 Ω / sq, while carrier mobility increases from 23.57 cm⁻¹. 2 / (V s) increased to 28.78cm 2 / (V s), with superior electrical performance.

[0087] Comparing Example 1 and Comparative Example 2, the bilayer structure of Comparative Example 2 lacks multiple interference optimization and sufficient conductive layer support, resulting in a visible light transmittance of 89.2% and a reflectance of 10.5%, indicating poor optical performance. Simultaneously, the single-layer 30nm indium oxide layer has limited carrier transport paths, with a sheet resistance of 60.1Ω / sq and a carrier mobility of 16.96cm⁻¹. 2 / (V The electrical performance of Example 1 is far inferior to that of Example 2. The multilayer design and transition layer of Example 1 work together to solve the optical loss problem and reduce transmission resistance by thickening the conductive layer, achieving a dual breakthrough in optical and electrical performance.

[0088] Comparative analysis of Example 1 and Comparative Example 3 revealed that Comparative Example 3, which did not dope the silicon oxide and indium oxide targets with barium and tin, directly led to a collapse in electrical performance. Without doping, the indium oxide layer lacked a source of charge carriers (oxygen vacancies and tin ions), resulting in poor interface matching between the silicon oxide layer and the substrate, and a sheet resistance spiked to 1.51 × 10⁻⁶. 5 Ω / sq, carrier mobility is only 1.36cm 2 / (V In Example 1, 0.2 wt% barium doping optimizes the silicon oxide layer interface, 10 wt% tin doping provides sufficient charge carriers for the indium oxide layer, and combined with a transition layer and annealing process, a low sheet resistance of 35.1 Ω / sq and a sheet resistance of 28.78 cm⁻¹ are achieved. 2 / (V The high mobility of s). In terms of optical performance, Comparative Example 3, due to the lack of doping, has more defects in the film layer, with a transmittance of 88.45% and a reflectance of 10.9%, which is far inferior to the excellent performance of Example 1, proving that barium doped silicon oxide and tin doped indium oxide can significantly improve carrier transport efficiency.

[0089] The above-described embodiments are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope of the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A TCO thin film, characterized in that, It includes, from bottom to top, a substrate, a first silicon oxide layer, a first indium oxide layer, a transition layer, a second indium oxide layer, and a second silicon oxide layer; the transition layer includes, from bottom to top, an indium oxide layer, a silicon oxide layer, and an indium oxide layer.

2. The TCO thin film as described in claim 1, characterized in that, The substrate is any one of glass, quartz, or plastic, and the thickness of the substrate is 500~700μm; The thickness of the first silicon oxide layer and the second silicon oxide layer are each independently 15~30nm; The thickness of the first indium oxide layer and the second indium oxide layer are each independently 25~35nm; The thickness of each indium oxide layer in the transition layer is independently 0.75~1.5nm, and the thickness of each silicon oxide layer in the transition layer is 0.5~1nm; the total thickness of the transition layer is 2~5nm.

3. The TCO film as described in claim 1 or 2, characterized in that, The first silicon oxide layer, the second silicon oxide layer, and the silicon oxide layer in the transition layer are all doped with barium, and the amount of barium doping is 0.15~0.25wt%. Tin is doped in the first indium oxide layer, the second indium oxide layer, and the indium oxide layer in the transition layer, with a tin doping amount of 10~11wt%.

4. The TCO film as described in claim 1 or 2, characterized in that, The resistance of the first silicon oxide layer and the second silicon oxide layer is 1×10⁻⁶. 5 ~5×10 6 Ω / sq, carrier mobility 1×10 -3 ~1×10 -2 cm 2 / (V·s); The resistivity of the first indium oxide layer and the second indium oxide layer is 28~45 Ω / sq, and the carrier mobility is 15~40 cm⁻¹. 2 / (V·s); The resistivity of the indium oxide layer in the transition layer is 30~50 Ω / sq, and the carrier mobility is 12~35 cm⁻¹. 2 / (V·s); The resistance of the silicon oxide layer in the transition layer is 8 × 10⁻⁶. 4 ~3×10 6 Ω / sq, carrier mobility 5×10 -4 ~8×10 - 3 cm 2 / (V·s).

5. A method for preparing a TCO thin film, characterized in that, include: Step 1: Deposit a first silicon oxide layer on the substrate surface using a magnetron sputtering process; Step 2: Deposit a first indium oxide layer on the surface of the first silicon oxide layer using a magnetron sputtering process; Step 3: A transition layer is deposited on the surface of the first indium oxide layer using a magnetron sputtering process. During the deposition of the transition layer, the indium oxide layer, the silicon oxide layer, and the indium oxide layer are deposited sequentially from bottom to top. Step 4: A second indium oxide layer and a second silicon oxide layer are sequentially deposited on the surface of the transition layer using a magnetron sputtering process.

6. The method for preparing the TCO thin film as described in claim 5, characterized in that, In step 1, when depositing the first silicon oxide layer, the deposition atmosphere is a mixture of oxygen and argon, the argon flow rate is 300~400 sccm, the oxygen flow rate is 0~100 sccm, the deposition temperature is 25~100℃, the deposition pressure is 0.5~0.6Pa, the radio frequency power is 5.5~6kW, the radio frequency is 15~25kHz, and the deposition rate is 1.0~1.5nm / s.

7. The method for preparing the TCO thin film as described in claim 5 or 6, characterized in that, In step 2, when depositing the first indium oxide layer, the deposition atmosphere is a mixture of oxygen and argon, with oxygen accounting for 1 vol% to 2.5 vol% and the remainder being argon. The deposition temperature is 25 to 75°C, the deposition pressure is 0.5 to 0.65 Pa, the radio frequency power is 5.5 to 6.5 kW, and the deposition rate is 4.29 to 5.25 nm / s.

8. The method for preparing the TCO thin film as described in claim 5, characterized in that, In step 3, when depositing the indium oxide layer, the deposition atmosphere is a mixture of oxygen and argon, with oxygen accounting for 0.5 vol% to 0.8 vol% and the remainder being argon. The deposition temperature is 25 to 75°C, the deposition pressure is 0.5 to 0.6 Pa, the radio frequency power is 5.5 to 6.5 kW, and the deposition rate is 4.5 to 4.85 nm / s.

9. The method for preparing the TCO thin film as described in claim 5 or 8, characterized in that, In step 3, when depositing the silicon oxide layer, the deposition atmosphere is a mixture of oxygen and argon, the argon flow rate is 300~400 sccm, the oxygen flow rate is 0~100 sccm, the deposition temperature is 25~100℃, the deposition pressure is 0.55~0.65Pa, the RF power is 5.5~6.5kW, the RF frequency is 15~25kHz, and the deposition rate is 1~2nm / s.

10. The method for preparing the TCO thin film as described in claim 5, characterized in that, Before step 1, the substrate is pretreated by ultrasonic cleaning in acetone, anhydrous ethanol and deionized water for 20-40 minutes in sequence. In step 4, the process parameters for depositing the second indium oxide layer are the same as those for depositing the first indium oxide layer in step 1. The process parameters for depositing the second silicon oxide layer are the same as those for depositing the first silicon oxide layer in step 1. Step 4 is followed by an annealing process, in which the thin film material obtained in step 3 is annealed at 200-230°C for 50-70 minutes in an air atmosphere.

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