Ultrathin transparent conductive electrode for laminated solar cell and preparation method and application of ultrathin transparent conductive electrode
By fabricating ultrathin transparent conductive electrodes through joint vacuum thermal evaporation of indium tin oxide and gold, the complexity of film formation and light loss in tandem solar cells were solved, thereby improving device performance and photoelectric conversion efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-04-07
AI Technical Summary
In existing technologies, the film formation process of tandem solar cells is complex and costly. The underlying perovskite film is easily damaged, and insufficient coverage of the charge recombination layer and light absorption lead to performance fluctuations, affecting process repeatability and photoelectric conversion efficiency.
An ultrathin transparent conductive electrode was prepared by co-vacuum thermal evaporation of indium tin oxide and gold as a charge recombination layer. This method simplifies the process, protects the underlying perovskite film, improves the coverage and conductivity of charge recombination sites, and reduces optical loss.
It simplifies operation, reduces costs, improves device yield and process repeatability, enhances charge recombination site coverage, and improves photoelectric conversion efficiency.
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Figure CN121815883A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor thin films, and more specifically, to an ultrathin transparent conductive electrode for tandem solar cells, its preparation method, and its application. Background Technology
[0002] The rapid development of perovskite-based tandem solar cell technology has significantly improved photoelectric conversion efficiency, powerfully promoting the commercialization of this type of cell. In monolithic tandem solar cells, the charge recombination layer, as a key structure for achieving efficient charge transport and recombination, has a decisive impact on the overall performance of the device due to its transparency and conductivity. It not only directly affects the efficiency and process repeatability of the tandem device, but also ultimately restricts the production pace and overall manufacturing efficiency.
[0003] Common processes for forming charge composite layers in tandem solar cells include SnO2 or TiO2 prepared by atomic layer deposition, and transparent conductive oxides such as ITO or IZO prepared by magnetron sputtering.
[0004] The existing technology has the following technical problems:
[0005] 1) The preparation processes of atomic layer deposition and magnetron sputtering are complex and costly;
[0006] 2) The underlying perovskite film is easily damaged during the film formation process, which leads to fluctuations in device performance and a decrease in yield, affecting the repeatability of the process.
[0007] 3) Insufficient coverage of the charge recombination layer leads to fewer recombination sites;
[0008] 4) The light loss caused by parasitic light absorption in the charge recombination layer is severe. Summary of the Invention
[0009] To address the shortcomings of existing technologies, this invention provides an ultrathin transparent conductive electrode for tandem solar cells and its fabrication method. The ultrathin transparent conductive electrode fabricated using this method, when used to construct tandem solar cells, significantly improves the photoelectric conversion efficiency of the tandem solar cells. This invention is achieved through the following technical solutions:
[0010] This invention discloses an ultrathin transparent conductive electrode for tandem solar cells, the electrode structure being a substrate and an electrode layer from bottom to top.
[0011] As a further improvement, the substrate of the present invention is glass; the electrode layer is a co-evaporation layer of indium tin oxide and gold.
[0012] This invention also discloses a method for preparing an ultrathin transparent conductive electrode for tandem solar cells, the specific steps of which are as follows:
[0013] Step 1: Clean the glass substrate. First, use dish soap, deionized water, acetone and isopropanol to ultrasonically clean for 10-15 minutes each. Then, use a dry nitrogen stream to dry the glass substrate.
[0014] Step two: Deposit the electrode layer onto the glass substrate cleaned in step one; reduce the vacuum level to 5 × 10⁻⁶. -4 Below Pa, indium tin oxide and gold are deposited at different thermal evaporation rates.
[0015] As a further improvement, the vacuum thermal evaporation rate of indium tin oxide in step two of this invention is...
[0016] As a further improvement, the vacuum thermal evaporation rate of gold in step two of this invention is...
[0017] As a further improvement, the deposition method in step two of this invention is co-vacuum thermal evaporation.
[0018] As a further improvement, the total deposition thickness in step two of this invention is 0.2-20 nm.
[0019] As a further improvement, the ultrathin transparent conductive electrode described in this invention is used in tandem solar cells.
[0020] The beneficial effects of this invention are as follows:
[0021] This invention discloses an ultrathin transparent conductive electrode for tandem solar cells and its fabrication method. The invention uses co-vacuum thermal evaporation of indium tin oxide and gold to prepare an ultrathin transparent conductive electrode, which is then used as a charge recombination layer in the fabrication of tandem solar cells.
[0022] This invention selects indium tin oxide and gold through joint vacuum thermal evaporation to prepare ultrathin transparent conductive electrodes. The advantages are simple operation, low cost, fast film formation rate, high film purity, and effective avoidance of material oxidation.
[0023] This invention selects co-vacuum thermal evaporation of indium tin oxide and gold to prepare ultrathin transparent conductive electrodes, which has the advantage of effectively protecting the perovskite film on the bottom of the device, improving device yield and process repeatability.
[0024] This invention selects indium tin oxide and gold to prepare ultrathin transparent conductive electrodes through co-vacuum thermal evaporation. The advantage of this is that the doping of gold can effectively cover the lower interface, provide sufficient charge recombination sites, and improve the conductivity of the electrode.
[0025] The present invention selects indium tin oxide and gold in a common vacuum thermal evaporation to prepare an ultrathin transparent conductive electrode. The advantage of this is that the doping of indium tin oxide can improve the light transmittance of the electrode and minimize light loss.
[0026] This invention selects indium tin oxide and gold to prepare ultrathin transparent conductive electrodes through co-vacuum thermal evaporation. The advantage of this method is that the prepared ultrathin transparent conductive electrodes can be effectively applied to optoelectronic semiconductor devices.
[0027] The ultrathin transparent conductive electrode prepared by co-vacuum thermal evaporation of indium tin oxide and gold can be further used to prepare tandem solar cells, which can effectively improve their photoelectric conversion efficiency. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of an ultrathin transparent conductive electrode structure;
[0029] Figure 2 Hall effect test results for transparent conductive electrodes of different thicknesses;
[0030] Figure 3 This is a schematic diagram of a semi-transparent device structure;
[0031] Figure 4 Transmittance diagrams for the two types of semi-transparent devices in Application Examples 1 and 2;
[0032] Figure 5 This is a schematic diagram of a stacked solar cell structure.
[0033] Figure 6 The JV curves are shown for the two types of tandem solar cells in Examples 3 and 4. Detailed Implementation
[0034] This invention provides an ultrathin transparent conductive electrode, such as Figure 1 As shown, the ultrathin transparent conductive electrode structure consists of a substrate and an electrode layer from bottom to top. The substrate is a glass substrate; the electrode layer is an ultrathin transparent conductive electrode co-evaporated from indium tin oxide and gold.
[0035] The method for preparing the above-mentioned ultrathin transparent conductive electrode includes the following steps:
[0036] Step 1: Clean the glass substrate;
[0037] The glass substrate cleaning method described in step one is as follows: First, use detergent, deionized water, acetone and isopropanol respectively for ultrasonic cleaning for 10-15 minutes each; then use dry nitrogen gas to dry the glass substrate.
[0038] Step 2: Deposit an electrode layer onto the glass substrate that has been cleaned in Step 1.
[0039] The electrode layer preparation method described in step two is as follows: reduce the vacuum level to 5 × 10⁻⁶. -4 Below Pa, indium tin oxide and gold are co-deposited at different thermal evaporation rates; the thermal evaporation rate of indium tin oxide is... The thermal evaporation rate of gold is The total thickness of the two deposits is 0.2-20 nm.
[0040] After the above steps are completed, an ultrathin transparent conductive electrode is obtained. The superior embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.
[0041] Example 1.
[0042] The glass substrate is placed in a vacuum thermal evaporation apparatus, and the vacuum level is reduced to 5 × 10⁻⁶. -4 Below Pa, Indium tin oxide is deposited at a rate of [missing information], while at [missing information] Gold was deposited at a rate of 4.4 nm, and the total thickness of the two deposited together was 4.4 nm. The resulting ultrathin transparent conductive electrode was labeled CRL-1.
[0043] Example 2.
[0044] The glass substrate is placed in a vacuum thermal evaporation apparatus, and the vacuum level is reduced to 5 × 10⁻⁶. -4 Below Pa, Indium tin oxide is deposited at a rate of [missing information], while at [missing information] Gold was deposited at a rate of evaporation, and the total thickness of the two deposited together was 8.8 nm. The resulting ultrathin transparent conductive electrode was labeled CRL-2.
[0045] Example 3.
[0046] The glass substrate is placed in a vacuum thermal evaporation apparatus, and the vacuum level is reduced to 5 × 10⁻⁶. -4 Below Pa, Indium tin oxide is deposited at a rate of [missing information], while at [missing information] Gold was deposited at a rate of 17.6 nm, and the total thickness of the two deposited together was 17.6 nm. The resulting ultrathin transparent conductive electrode was labeled CRL-3.
[0047] Hall effect testing for co-evaporation of indium tin oxide and gold, as follows: Figure 2 As shown, the bulk resistance R-Bulk and sheet resistance R-sheet decreased by nearly two orders of magnitude as the charge transport layer (CRL) thickness increased from 4.4 nm to 17.6 nm. This ensures that the stacked device can still achieve ohmic contact even when the CRL is thin enough. On the other hand, CRL-1 (thickness = 4.4 nm) shows a sufficiently high R-sheet value to avoid leakage current.
[0048] Compare with Example 1.
[0049] The glass substrate is placed in a vacuum thermal evaporation apparatus, and the vacuum level is reduced to 5 × 10⁻⁶. -4 Below Pa, Silver was deposited at a rate of 1 nm, and the resulting conductive electrode was labeled CRL-4.
[0050] Application example 1.
[0051] In Application Example 1, a semi-transparent device STD-1 was fabricated using the ultrathin transparent conductive electrode CRL-1 obtained in Example 1 to test its permeability in a tandem battery. Figure 3 As shown, its structure is: ITO / 2PACz / PVSK / C 60 / BCP / CRL-1. Spin-coat the 2PACz solution onto an ITO substrate at 5000 rpm for 30 s, anneal at 100°C for 5 min. Dissolve CsI, FAI, PbI2, and PbBr2 (molar ratio = 0.17:0.83:1.65:1.35) in a DMF:DMSO mixture (volume ratio = 9:1) and stir at room temperature until dissolved. Spin-coat the mixture onto the 2PACz substrate at 5000 rpm, anneal at 100°C for 10 min. Reduce the vacuum to 5 × 10⁻⁵. -4 Below Pa, C rate evaporation 60 Its thickness is 25nm. BCP was deposited at a rate of [rate missing], with a thickness of 5 nm. Indium tin oxide is deposited at a rate of [missing information], while at [missing information] Gold was deposited at a rate of evaporation, and the total thickness of the two deposited together was 4.4 nm.
[0052] Application Example 2.
[0053] In Application Example 2, a semi-transparent device STD-2 was fabricated using the ultrathin transparent conductive electrode CRL-4 obtained in Comparative Example 1 to test its transmittance in a tandem solar cell. Its structure is: ITO / 2PACz / PVSK / C 60 / BCP / CRL-4. Spin-coat the 2PACz solution onto an ITO substrate at 5000 rpm for 30 s, anneal at 100°C for 5 min. Dissolve CsI, FAI, PbI2, and PbBr2 (molar ratio = 0.17:0.83:1.65:1.35) in a DMF:DMSO mixture (volume ratio = 9:1) and stir at room temperature until dissolved. Spin-coat the mixture onto the 2PACz substrate at 5000 rpm, anneal at 100°C for 10 min. Reduce the vacuum to 5 × 10⁻⁵. -4 Below Pa, C rate evaporation 60 Its thickness is 25nm. BCP was deposited at a rate of [rate missing], with a thickness of 5 nm. Silver was deposited at a rate of 1 nm.
[0054] like Figure 4 As shown, STD-1 obtained in Example 1 exhibits good transmittance in the 700-1000 nm range. In contrast, STD-2 obtained in Comparative Example 1 has lower transmittance in the 700-1000 nm range than STD-1.
[0055] Application example 3.
[0056] In Application Example 3, the ultrathin transparent conductive electrode CRL-1 obtained in Example 1 was further used to fabricate a tandem solar cell TSC-1, as follows: Figure 5 As shown, its structure is: ITO / 2PACz / PVSK / C 60 / BCP / CRL-1 / MoO x / PM6:BO-4Cl / PDINN / Ag. Based on STD-1 obtained in Example 1, with MoO evaporation rate x The thickness was 20 nm. PM6 and BO-4Cl were mixed at a mass ratio of 1:1.8 and dissolved in a mixed solvent of chloroform and 1,8-diiodooctane to prepare an active layer solution with a concentration of 35 mg / mL. The solution was stirred at room temperature for 4 h, with the volume percentage of 1,8-diiodooctane being 0.25%. The active layer solution was spin-coated at 2000 rpm and annealed at 100 °C for 10 min. PDINN solution was spin-coated onto the active layer as an electron transport layer at 3000 rpm for 30 s. The vacuum was reduced to 5 × 10⁻⁶. -4 Below Pa, The metal Ag was deposited at a rate of 80 nm as the top electrode.
[0057] At AM1.5G 100mW / cm 2 Under the illumination conditions, the JV performance curves of the fabricated tandem solar cell device were tested, and the results are as follows: Figure 6 As shown. The performance parameters of the tandem solar cell TSC-1 are: open-circuit voltage 2.062V, short-circuit current density 14.53mA / cm². 2 The fill factor is 79.10%, and the photoelectric conversion efficiency is 23.7%.
[0058] Application example 4.
[0059] In Application Example 4, the ultrathin transparent conductive electrode CRL-4 obtained in Comparative Example 1 was used to further fabricate a tandem solar cell TSC-2, the structure of which is: ITO / 2PACz / PVSK / C 60 / BCP / CRL-4 / MoO x / PM6:BO-4Cl / PDINN / Ag. Based on STD-2 obtained in Example 2, with MoO evaporation rate x The thickness was 20 nm. PM6 and BO-4Cl were mixed at a mass ratio of 1:1.8 and dissolved in a mixed solvent of chloroform and 1,8-diiodooctane to prepare an active layer solution with a concentration of 35 mg / mL. The solution was stirred at room temperature for 4 h, with the volume percentage of 1,8-diiodooctane being 0.25%. The active layer solution was spin-coated at 2000 rpm and annealed at 100 °C for 10 min. PDINN solution was spin-coated onto the active layer as an electron transport layer at 3000 rpm for 30 s. The vacuum was reduced to 5 × 10⁻⁶. -4 Below Pa, The metal Ag was deposited at a rate of 80 nm as the top electrode.
[0060] At AM1.5G 100mW / cm 2 Under the illumination conditions, the JV performance curves of the fabricated tandem solar cell device were tested, and the results are as follows: Figure 6 As shown. The performance parameters of the tandem solar cell TSC-2 are: open-circuit voltage 2.015V, short-circuit current density 13.56mA / cm². 2 The fill factor is 80.15%, and the photoelectric conversion efficiency is 21.9%.
[0061] Compared with the tandem solar cell TSC-2 prepared by CRL-4, the tandem solar cell TSC-1 prepared by CRL-1 ultrathin transparent conductive electrode has significantly improved open-circuit voltage, short-circuit current density and cell efficiency, especially the photoelectric conversion efficiency of the cell is improved by more than 8.2%.
[0062] The above embodiments are merely illustrative of several specific implementations of the present invention and should not be construed as limiting the scope of the present invention. Any modifications, substitutions, and improvements made by those skilled in the art without departing from the design and concept of the present invention should be included within the scope of protection of the present invention.
Claims
1. An ultrathin transparent conductive electrode for tandem solar cells, characterized in that, The electrode structure consists of a substrate and an electrode layer from bottom to top.
2. The ultrathin transparent conductive electrode for tandem solar cells according to claim 1, characterized in that, The substrate is glass; the electrode layer is a co-evaporated layer of indium tin oxide and gold.
3. A method for preparing an ultrathin transparent conductive electrode for tandem solar cells as described in claim 1 or 2, characterized in that, The steps are as follows: Step 1: Clean the glass substrate. First, use dish soap, deionized water, acetone, and isopropanol to ultrasonically clean the glass substrate for 10-15 minutes each. Then, use a dry nitrogen stream to dry the glass substrate. Step two: Deposit the electrode layer onto the glass substrate cleaned in step one; reduce the vacuum level to 5 × 10⁻⁶. -4 Below Pa, indium tin oxide and gold are deposited at different thermal evaporation rates.
4. The method for preparing the ultrathin transparent conductive electrode according to claim 3, characterized in that, The vacuum thermal evaporation rate of indium tin oxide in step two is 5. The method for preparing the ultrathin transparent conductive electrode according to claim 3, characterized in that, The vacuum thermal evaporation rate of gold in step two is 6. The method for preparing an ultrathin transparent conductive electrode according to claim 4 or 5, characterized in that, The deposition method in step two is co-vacuum thermal evaporation.
7. The method for preparing the ultrathin transparent conductive electrode according to claim 6, characterized in that, The total deposition thickness in step two is 0.2-20 nm.
8. The application of an ultrathin transparent conductive electrode for tandem solar cells as described in claim 1 or 2 in tandem solar cells.