Aluminum-doped FTO (fluorine-doped tin oxide) conductive glass, preparation method thereof and application of aluminum-doped FTO conductive glass in perovskite solar cell
By spin-coating the aluminum source on the FTO surface and performing gradient annealing treatment, co-doping of F and Al is achieved, and the problem of degradation of the conductivity of the FTO film is solved, and a high-performance AFTO film suitable for perovskite solar cells is prepared, reducing costs and improving conductivity.
Patent Information
- Application Number
- CN202510689517.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-27
- Publication Date
- 2025-07-08
AI Technical Summary
The existing transparent conductive oxide films such as FTO have lattice distortion at high doping concentrations lead to a decrease in conductivity, which is difficult to meet the high requirements of electronic devices. The traditional preparation methods are costly and wasteful of raw materials.
The post-treatment spin coating doping method is adopted, and the aluminum source solution is spin-coated on the FTO surface and then gradient annealing is performed to achieve co-doping of F and Al, and AFTO film is prepared, which improves the conductivity through the diffusion of aluminum elements to the SnO2 lattice.
The prepared AFTO film has lower resistivity and higher carrier mobility, and is suitable for perovskite solar cells. It has low process cost, simple process and saves raw materials.
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Figure CN120271244A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of transparent conductive oxide (TCO) films, and in particular to a technology for preparing F, Al co-doped tin oxide (AFTO) conductive glass by introducing aluminum (Al) elements into a fluorine-doped tin oxide (FTO) film manufactured by a chemical vapor deposition (CVD) method through a post-treatment process, and application of the technology in perovskite solar cells. Background Art
[0002] In the research and industrial application of transparent conductive oxide conductive glass, fluorine-doped tin oxide (FTO) films are widely used in solar cells, flat panel displays, energy-saving glass and other fields due to their advantages such as high conductivity, high transmittance in the visible light region and low cost. However, with the advancement of science and technology and the development of production applications, electronic devices have put forward higher requirements on the optical and electrical properties of SnO2-based transparent conductive films (such as lower resistivity, higher carrier mobility, and better environmental stability). In order to effectively regulate the physical properties of oxide films and expand their application areas, researchers have systematically investigated the doping effects of various elements such as Sb, F, Mo, Li and Nd on SnO2-based transparent conductive films. Among them, fluorine is currently considered to be the most important doping element, because fluorine doping can significantly improve the optical and electrical properties of tin oxide films, and fluorine-doped tin dioxide films (FTO) are commercially important. However, due to the F - Bottleneck of single doping When the F doping concentration exceeds 3at%, about 38% of F - The ions occupy the interstitial sites of the SnO2 lattice (rather than replacing O 2- sites), resulting in an increase in lattice distortion energy of 0.7 eV (calculated by density functional theory), which in turn causes a significant carrier scattering effect, which is not conducive to improving the conductive properties of the film (BILGIN V, AKYUZ I, KETENCI E, et al. Electrical, structural and surface properties of fluorine doped tin oxide films[J]. Applied Surface Science, 2010, 256(22): 6586-6591).
[0003] To meet the requirements of people for the optoelectronic properties of transparent conductive glass, among many process preparation technologies, an effective method is to perform multi-element doping, hoping to improve the optical and electrical properties of the thin film by doping with a variety of different elements. Aluminum is the most abundant metal element in the earth's crust and has many excellent properties. It is inexpensive, non-toxic, and pollution-free. Using aluminum as a doping element to prepare high-performance TCO thin film materials has gradually received the attention of researchers. The existing literature (LI Z, SONGJ, DUAN X, et al. F and Al co-doped zinc oxide thin films deposited byultrasonic spray pyrolysis: Effects of substrate temperature on physicalproperties[J]. Journal of Alloys and Compounds, 2021, 858: 158076) reported a kind of F, Al co-doped zinc oxide transparent conductive thin film (FAZO). Using zinc acetate, ammonium fluoride, and aluminum nitrate as Zn, F, and Al sources respectively, FAZO thin film was deposited on a glass substrate by ultrasonic spray pyrolysis. The FAZO thin film prepared at 480 °C has the best optoelectronic properties: the mobility is 22.9 cm 2 / (Vs), the carrier concentration is 1.75×10 20 cm -3 , the resistivity is 1.56×10 -3 Ω cm, and the transmittance in the range of 400~1400 nm is above 85%. This method can prepare FAZO with a flat and dense structure and good comprehensive optoelectronic properties, but its conductivity still cannot meet the requirements of commercial electronic devices, and a large amount of raw materials will be wasted during the spraying process of atomizing the precursor solution by ultrasonic spray pyrolysis. Summary of the Invention
[0004] The present invention provides an aluminum post-doped FTO conductive glass, its preparation method, and its application in perovskite solar cells. The post-treatment spin-coating doping preparation method of the present invention has lower process cost, simpler process flow, and can save a large amount of raw materials. Compared with the original FTO, the co-doped AFTO thin film prepared has better conductive properties and can be applied to the preparation of perovskite solar cells.
[0005] The specific technical solutions are as follows: In the first aspect, the present invention provides a preparation method of an aluminum post-doped FTO conductive glass, including: spin-coating an aluminum source solution on the surface of a clean FTO and performing a pre-curing treatment, and transferring the pre-cured FTO to an inert gas atmosphere for gradient annealing treatment to obtain the aluminum post-doped FTO conductive glass; The temperature of the pre-curing treatment is 80~200 °C, such as 120 °C, 150 °C, etc.; The gradient annealing treatment includes two stages. The annealing temperature in the first stage is 250~350 °C, such as 280 °C, etc., and the annealing temperature in the second stage is 350~500 °C, such as 380 °C, 400 °C, 450 °C, etc.
[0006] The preparation method of the present invention is a simple and efficient post-treatment doping method. Using fluorine-doped tin oxide (FTO) glass prepared by chemical vapor deposition (CVD) method as the substrate, F and Al co-doped tin oxide transparent conductive thin film (AFTO) is realized. By spin-coating the aluminum precursor solution and combining the gradient annealing process, the efficient diffusion of aluminum element into the SnO2 lattice is achieved, and finally a co-doped thin film with high conductivity, high light transmittance and environmental stability is obtained. Compared with the original FTO, the AFTO has better conductivity and can be applied to the preparation of perovskite solar cells (PSC).
[0007] In order to make the resistance of the aluminum post-doped FTO conductive glass lower and the carrier mobility higher, the mass density of aluminum spin-coated on the FTO surface is preferably 0.001~0.15 g / cm 2 , such as 0.004 g / cm 2 , 0.025 g / cm 2 , 0.06 g / cm 2 , 0.07 g / cm 2 , 0.08 g / cm 2 , 0.09 g / cm 2 , 0.1 g / cm 2 etc., and further preferably 0.025~0.07 g / cm 2 .
[0008] In order to make the resistance of the aluminum post-doped FTO conductive glass lower and the carrier mobility higher, the concentration of the aluminum source in the aluminum source solution is preferably 0.01~0.1 g / mL, such as 0.02 g / mL, 0.05 g / mL, 0.07 g / mL, etc., and further preferably 0.02~0.05 g / mL.
[0009] Preferably, the aluminum source includes any one of aluminum acetylacetonate (Al(acac)3), aluminum nitrate (Al(NO3)3), and aluminum isopropoxide (Al(OPri)3).
[0010] Preferably, the solvent in the aluminum source solution includes one or more of methanol, ethanol, n-propanol, and isopropanol.
[0011] The aluminum source solution can be obtained through the following process: adding an aluminum source to a solvent, ultrasonically dispersing it, and then stirring it to completely dissolve the aluminum source, thereby obtaining the aluminum source solution. The time for ultrasonic dispersion can be 5 - 30 min, such as 10 min, 15 min, 20 min, etc. The time for stirring can be 0.5 - 3 h, such as 1 h, 2 h, 2.5 h, etc.
[0012] Preferably, the clean FTO is obtained by ultrasonically cleaning, drying the FTO, and then placing it in an ultraviolet ozone cleaning machine for treatment to remove surface impurities, which can improve the surface wettability of the FTO.
[0013] Preferably, the rotation speed for spin coating is 3000 - 5000 rpm, such as 3500 rpm, 4000 rpm, etc.
[0014] Preferably, the time for spin coating is 20 - 45 s, such as 25 s, 30 s, etc.
[0015] The pre - curing treatment can be carried out in air.
[0016] Preferably, the time for the pre - curing treatment is 5 - 15 min, such as 10 min, etc.
[0017] Preferably, the heating rate for the gradient annealing treatment is 5 - 10 °C / min, Preferably, the annealing time for the first stage is 30 - 60 min.
[0018] Preferably, the annealing time for the second stage is 60 - 180 min.
[0019] In the present invention, the inert gas atmosphere refers to a gas atmosphere that does not participate in the reaction, such as one or more of a nitrogen atmosphere, an argon atmosphere, etc.
[0020] In a second aspect, the present invention provides an aluminum - post - doped FTO conductive glass prepared by the preparation method described in the first aspect.
[0021] In a third aspect, the present invention provides the application of the aluminum - post - doped FTO conductive glass described in the second aspect in a perovskite solar cell device.
[0022] As a general inventive concept, in a fourth aspect, the present invention provides a perovskite solar cell device, which includes an aluminum - post - doped FTO conductive glass, an SnO2 electron transport layer, a perovskite light - absorbing layer, a passivation layer, a hole transport layer, and a metal electrode that are sequentially stacked, as described in the second aspect.
[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. Compared with the traditional method of doping to prepare transparent conductive films, the post-treatment spin-coating preparation method of the present invention has lower process costs, a simpler process flow, and can save a large amount of raw materials.
[0024] 2. The AFTO prepared by the post-treatment spin-coating preparation method has better conductivity compared to FTO, with a significantly improved carrier mobility, a lower resistivity, and is more suitable for the preparation of perovskite solar cells. Brief Description of the Drawings
[0025] Figure 1 It is the X-ray diffraction (XRD) pattern of AFTO and FTO prepared in Examples 1 to 4 of the present invention, and the enlarged views in the diffraction angle ranges of 26° to 28° and 36° to 40°.
[0026] Figure 2 It is the Al2p binding energy sub-spectrum in the X-ray photoelectron spectroscopy (XPS) of AFTO and FTO prepared in Examples 1 to 4 of the present invention.
[0027] Figure 3 It is the statistical chart of the electrical properties of AFTO and FTO prepared in Examples 1 to 4 of the present invention, where: (a) is the sheet resistance; (b) is the resistivity; (c) is the carrier concentration; (d) is the mobility.
[0028] Figure 4 It is the schematic diagram of the device structure of the formal PSCs based on AFTO / FTO obtained in Application Example 1 of the present invention.
[0029] Figure 5 It is the J-V curve diagram of the formal PSCs prepared based on FTO in Application Example 1 of the present invention.
[0030] Figure 6 It is the J-V curve diagram of the formal PSCs prepared based on AFTO in Application Example 1 of the present invention. Detailed Embodiments
[0031] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The operating methods without specific conditions noted in the following embodiments are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer.
[0032] Example 1: (1) Weigh the reaction raw materials. Dissolve 0.1 g of aluminum acetylacetonate in 10 mL of methanol. After 10 min of ultrasonic dispersion, stir for 0.5 h to completely dissolve the aluminum acetylacetonate; make the concentration of aluminum acetylacetonate in the mixed solution 0.01 g / mL; After cleaning the FTO, 300 μL of the mixed solution was spin-coated on the surface of the FTO with an area of 2 square centimeters at a spin-coating speed of 3000 rpm for 25 s. After spin-coating, a pre-curing treatment was carried out in the air at 120 °C for 10 min. (3) The FTO spin-coated and pre-cured in step (2) was placed in a high-temperature tube furnace. Under a nitrogen atmosphere, it was heated to 280 °C at a heating rate of 10 °C / min, held for 30 min, then heated to 350 °C at a heating rate of 10 °C / min, held for 60 min, and cooled to obtain AFTO.
[0033] Example 2: (1) Weigh the reaction raw materials. Dissolve 0.6 g of aluminum acetylacetonate in 20 mL of methanol, perform ultrasonic dispersion for 15 min, and then stir for 1 h to completely dissolve the aluminum acetylacetonate, so that the concentration of aluminum acetylacetonate in the mixed solution is 0.03 g / mL. After cleaning the FTO, 300 μL of the mixed solution was spin-coated on the surface of the FTO with an area of 2 square centimeters at a spin-coating speed of 3500 rpm for 30 s. After spin-coating, a pre-curing treatment was carried out in the air at 150 °C for 10 min. (3) The FTO spin-coated and pre-cured in step (2) was placed in a high-temperature tube furnace. Under an argon atmosphere, it was heated to 280 °C at a heating rate of 10 °C / min, held for 30 min, then heated to 380 °C at a heating rate of 10 °C / min, held for 60 min, and cooled to obtain AFTO.
[0034] Example 3: (1) Weigh the reaction raw materials. Dissolve 1 g of aluminum isopropoxide in 20 mL of isopropanol, perform ultrasonic dispersion for 20 min, and then stir for 2 h to completely dissolve the aluminum isopropoxide, so that the concentration of aluminum isopropoxide in the mixed solution is 0.05 g / mL. After cleaning the FTO, 300 μL of the mixed solution was spin-coated on the surface of the FTO with an area of 2 square centimeters at a spin-coating speed of 4000 rpm for 25 s. After spin-coating, a pre-curing treatment was carried out in the air at 120 °C for 15 min. (3) The FTO spin-coated and pre-cured in step (2) was placed in a high-temperature tube furnace. Under an argon atmosphere, it was heated to 280 °C at a heating rate of 10 °C / min, held for 30 min, then heated to 400 °C at a heating rate of 10 °C / min, held for 60 min, and cooled to obtain AFTO.
[0035] Example 4: (1) Weigh the reaction raw materials. Dissolve 1.4 g of aluminum nitrate in a mixed solution of 20 mL of ethanol and isopropanol. After ultrasonic dispersion for 30 min, stir for 2.5 h to completely dissolve the aluminum nitrate, so that the concentration of aluminum nitrate in the mixed solution is 0.07 g / mL. (2) After cleaning the FTO, take 300 μL of the mixed solution and spin-coat it on the surface of the FTO with an area of 2 square centimeters at a spin-coating speed of 3000 rpm for 25 s. After spin-coating, perform a pre-curing treatment in air at 120 °C for 15 min. (3) Place the FTO spin-coated and pre-cured in step (2) in a high-temperature tube furnace. Under a nitrogen atmosphere, heat it to 280 °C at a heating rate of 10 °C / min, hold for 30 min, then heat it to 450 °C at a heating rate of 10 °C / min, hold for 60 min, and cool to obtain AFTO.
[0036] Application Example 1: The formal perovskite solar cells (PSCs) prepared based on the AFTO or FTO of Examples 1-4 have the following device structure: AFTO (or FTO) / SnO2 electron transport layer / perovskite light-absorbing layer / phenethylamine iodide (PEAI) layer / hole transport layer (Spiro-OMeTAD) / silver electrode (see Figure 4 ), and the specific device preparation steps are as follows: 1) First, perform surface treatment on the AFTO or FTO substrate to ensure good adhesion and wettability. The specific steps are as follows: Use a glass cleaning solution, deionized water, and isopropanol to ultrasonically clean the substrate for 15 min each, then blow dry the substrate with nitrogen, and further treat it with an ultraviolet ozone machine for 15 min to improve the wettability of the substrate.
[0037] 2) Use a 3wt% concentration of SnO2 water mixture to spin-coat on the AFTO or FTO at an acceleration of 2500 rpm / s to 4000 rpm for 25 s, and then anneal at 150 °C for 30 min to form an electron transport layer on the surface of the AFTO or FTO.
[0038] 3) Dissolve a mixture of 880.5 mg of lead iodide (PbI2), 309.5 mg of formamidinium hydroiodide (FAI), and 42.5 mg of methylammonium chloride (MACl) in a mixed solvent of 800 μL of N,N-dimethylformamide (DMF) and 200 μL of dimethyl sulfoxide (DMSO), and stir to dissolve to prepare a perovskite precursor solution.
[0039] 4) 0.1 mL of the perovskite precursor solution was dropped onto the electron transport layer of the AFTO or FTO conductive glass, accelerated to 4000 rpm at an acceleration of 2000 rpm / s, and spin-coated for 30 s. 100 μL of chlorobenzene (CB) was dropped during the last 10 s for pre-crystallization nucleation operation, and then annealed at 150 °C for 30 min in an air environment to complete the preparation of the perovskite layer.
[0040] 5) 4.5 mg of phenethylammonium iodide was dissolved in 1 mL of isopropanol to prepare the passivation layer solution. Then the solution was dropped onto the perovskite film, accelerated to 3000 rpm at an acceleration of 1000 rpm / s, and spin-coated for 30 s.
[0041] 6) 90 mg of Spiro-OMeTAD was dissolved in 1 mL of CB, 20 μL of Li-TFSI solution (500 mg / mL dissolved in acetonitrile) and 40 μL of 4-tert-butylpyridine were added to prepare the hole transport layer precursor solution. Then the solution was dropped onto the passivation layer, accelerated to 5000 rpm at an acceleration of 2000 rpm / s, and spin-coated for 30 s.
[0042] 7) Using a vacuum coater, under a vacuum of <5×10 -4 Pa, a metal silver electrode with a thickness of 80 nm was deposited by evaporation at a speed of 0.15 nm / s. The effective area of a single sub-cell was 0.04 cm 2 .
[0043] The samples of Examples 1 to 4 and Application Example 1 were analyzed as follows: Figure 1 This is the X-ray diffraction pattern of AFTO and FTO prepared in Examples 1 to 4 of the present invention, and the enlarged views in the diffraction angle ranges of 26° to 28° and 36° to 40°. The XRD spectra of each example showed a tetragonal rutile-type SnO2 phase, and no diffraction peaks of metallic Al or Al2O3 appeared, confirming that Al atoms replaced Sn atoms. Compared with the peaks of the undoped FTO, the peak positions of the AFTO thin films shifted to the high-angle region, and with the increase in the aluminum source concentration (the aluminum source concentration gradually increased from Example 1 to Example 4), the peak shift of the AFTO thin films was more obvious. This displacement should be attributed to the expansion of the SnO2 lattice. Al 3+ (0.535 Å) is about 23% smaller than Sn 4+ (0.69 Å). When Al 3+ replaces Sn in the SnO2 lattice 4+ , the smaller Al 3+ will compress the arrangement space of the surrounding oxygen ions, resulting in the overall contraction of the unit cell. The contraction of the unit cell leads to a decrease in the adjacent crystal plane spacing. Therefore, the XRD peaks shift to higher angles, which also proves the successful doping of Al.
[0044] Figure 2 This is the Al 2p binding energy sub-spectrum in the X-ray photoelectron spectroscopy of AFTO and FTO prepared in Examples 1-4 of the present invention. As can be seen from the figure, the peak of Al 2p is approximately at a binding energy of 74.5 eV. As the concentration of the aluminum source increases, the number of sites where Al 3+ substitutes for Sn 4+ increases, and the intensity of the photoelectron signal of the Al 2p orbital detected by XPS will gradually increase. The peak area and intensity of Al 2p are positively correlated with the doping concentration, and the Al 2p peak in each example only shows a single peak without broadening, indicating that Al does not exist in the form of Al2O3 or metallic Al, which shows that the doping process does not lead to phase separation, and Al 3+ is uniformly distributed in the SnO2 lattice.
[0045] Figure 3 This is the statistical chart of the electrical properties of AFTO and FTO prepared in Examples 1-4 of the present invention, where: (a) is the sheet resistance; (b) is the resistivity; (c) is the carrier concentration; (d) is the mobility. During the doping process, Al 3+ substitutes for Sn 4+ to introduce holes, and the introduced holes will compensate for the donor electrons of F - , which will directly reduce the net carrier (electron) concentration. However, the introduction of Al 3+ suppresses the high-density random oxygen vacancy clusters in the SnO2 lattice, reduces the ionized impurity scattering, and at the same time optimizes the lattice periodicity, improving the carrier mobility. Therefore, under the condition of low aluminum source concentration, the low-aluminum-doped AFTO achieved has a slightly decreased carrier concentration due to acceptor compensation, but the increase in mobility offsets its influence, and the overall resistivity and sheet resistance both decrease significantly. From Figure 3 it can be seen that the AFTO prepared in Example 2 has the lowest resistance and the highest carrier mobility.
[0046] Figure 4 This is the schematic diagram of the device structure of the formal PSCs based on AFTO / FTO obtained in Application Example 1 of the present invention. The device structure is AFTO or FTO / SnO2 electron transport layer / perovskite absorption layer / phenethylamine iodide (PEAI) passivation layer / hole transport layer (Spiro-OMeTAD) / silver electrode.
[0047] Figure 5 、 Figure 6 are respectively the J-V curves of the formal PSCs prepared based on FTO and AFTO in Application Example 1 of the present invention. When performing reverse scanning, the open-circuit voltage of the device based on FTO is 1.143 V, and the short-circuit current density is 23.94 mA / cm 2, the fill factor is 72.27%, and the photoelectric conversion efficiency is 20.07%. The open-circuit voltage of the AFTO-based device is 1.152 V, and the short-circuit current density is 24.27 mA / cm 2 , the fill factor is 75.9%, and the photoelectric conversion efficiency is 21.27%. It can be proved that using AFTO to prepare PSCs can bring obvious improvement in device performance.
[0048] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.
Claims
1. A preparation method of an aluminum post-doped FTO conductive glass, characterized in that, Including: Spin-coating an aluminum source solution on the surface of a clean FTO and performing a pre-curing treatment, and transferring the pre-cured FTO to an inert gas atmosphere for gradient annealing treatment to obtain the post-aluminum-doped FTO conductive glass; The temperature of the pre-curing treatment is 80-200 °C; The gradient annealing treatment includes two stages, wherein the annealing temperature in the first stage is 250-350 °C, and the annealing temperature in the second stage is 350-500 °C.
2. The preparation method according to claim 1, characterized in that, The mass density of aluminum spin-coated on the FTO surface is 0.001 to 0.15 g / cm 2 , preferably 0.025 to 0.07 g / cm 2 ; The concentration of the aluminum source in the aluminum source solution is 0.01-0.1 g / mL, preferably 0.02-0.05 g / mL; The aluminum source includes any one of aluminum acetylacetonate, aluminum nitrate, and aluminum isopropoxide.
3. The preparation method according to claim 1, characterized in that, The solvent in the aluminum source solution includes one or more of methanol, ethanol, n-propanol, and isopropanol.
4. The preparation method according to claim 1, characterized in that, The clean FTO is obtained by ultrasonically cleaning, drying the FTO and then placing it in an ultraviolet ozone cleaner for treatment to remove surface impurities.
5. The preparation method according to claim 1, characterized in that, The rotation speed of the spin-coating is 3000-5000 rpm, and the spin-coating time is 20-45 s.
6. The preparation method according to claim 1, wherein The time of the pre-curing treatment is 5-15 min.
7. The preparation method according to claim 1, characterized in that, The heating rate of the gradient annealing treatment is 5-10 °C / min, the annealing time in the first stage is 30-60 min, and the annealing time in the second stage is 60-180 min.
8. The post-aluminum-doped FTO conductive glass prepared by the preparation method according to any one of claims 1-7.
9. The application of the post-aluminum-doped FTO conductive glass according to claim 8 in a perovskite solar cell device.
10. A perovskite solar cell device, characterized in that, Including the post-aluminum-doped FTO conductive glass, SnO2 electron transport layer, perovskite light-absorbing layer, passivation layer, hole transport layer, and metal electrode according to claim 8 stacked in sequence.