Inorganic / organic doped hole transport material, preparation method and application thereof

Abstract

This invention belongs to the field of photovoltaic materials technology, specifically relating to an inorganic / organic doped hole transport material, its preparation method, and its applications. The inorganic / organic doped hole transport material comprises an organic matrix and an inorganic dopant phase dispersed within the organic matrix; the amount of the inorganic dopant phase added accounts for 5% to 20% of the total mass of the organic matrix; the inorganic dopant phase is nanoparticles or quantum dots whose surface has been modified with short-chain organic molecules. This invention, through the synergistic design of inorganic / organic doping, fundamentally solves the core bottlenecks of poor interfacial contact in pure inorganic materials and low charge mobility in pure organic materials.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic materials technology, specifically relating to an inorganic / organic doped hole transport material, its preparation method, and its application. Background Technology

[0002] Against the backdrop of a escalating global energy crisis and environmental problems, solar cells, as a core technology for renewable energy utilization, have become a key pathway to achieving the "dual carbon" goal. Among them, cadmium telluride (CdTe) solar cells stand out due to their high light absorption coefficient (reaching 10 in the visible light band). 5 cm -1 With its advantages such as the above, suitable bandgap (approximately 1.45 eV, with excellent matching with the solar spectrum), low manufacturing cost, and mature large-scale production, it has become one of the most widely used thin-film solar cells in commercial applications.

[0003] A typical cadmium telluride solar cell device employs a layered structure consisting of a substrate, a back contact layer, a light-absorbing layer (CdTe), a window layer, and a transparent conductive layer. The core functional layers include a p-type CdTe light-absorbing layer, an n-type window layer (such as CdS or ZnO), and a hole transport layer (back contact layer). The hole transport layer, as a crucial component connecting the CdTe light-absorbing layer and the back electrode, efficiently extracts photogenerated holes from the CdTe layer and transports them directionally to the back electrode, while simultaneously suppressing carrier recombination and reducing interfacial contact resistance. Its performance directly determines the device's photoelectric conversion efficiency, long-term operational stability, and potential for industrial applications.

[0004] Currently, the hole transport materials commonly used in cadmium telluride solar cells are mainly pure inorganic materials. Although pure inorganic hole transport materials (such as NiO) x While inorganic materials (such as CuI, Cu2O, and Sb2S3) possess advantages like high hole mobility, strong chemical stability, and good weather resistance, they also have significant drawbacks: poor energy level matching with the CdTe light-absorbing layer leads to a high hole extraction barrier and severe carrier recombination; poor interfacial compatibility easily forms an interface layer with high defect state density, increasing interfacial contact resistance; and the film-forming process of some inorganic materials (such as CuI) is complex, resulting in poor film uniformity and defects such as pinholes and cracks, affecting batch-to-batch consistency of devices. Therefore, existing pure inorganic hole transport materials cannot simultaneously meet the demands for high charge transport efficiency, good interfacial compatibility, excellent long-term stability, and low-cost scalable industrialization. In large-area module fabrication, the stability issues of interfacial contact problems with pure inorganic materials are further amplified, leading to rapid module efficiency decay and shortened lifespan, becoming a core bottleneck restricting the development of cadmium telluride solar cells towards higher efficiency, longer lifespan, and lower cost.

[0005] To address the above problems, the existing technology field has mainly developed the following improvement paths: (1) Inorganic material surface modification scheme: By modifying the surface of pure inorganic hole transport materials (such as NiO) x Surface modification can be performed to improve interfacial compatibility with the CdTe layer. However, this approach has a core drawback: the thickness of the surface modification layer is difficult to control precisely (too thick will increase charge transport resistance, while too thin will not effectively improve the interface), and the modification process will increase the complexity and cost of the preparation process; the energy level matching problem of the modified material is not fundamentally solved, the hole extraction efficiency is only slightly improved, and the long-term stability is not significantly improved.

[0006] (2) Develop optimization schemes for pure organic materials: develop novel pure organic hole transport materials through molecular structure design, or dope existing organic materials (such as Spiro-OMeTAD, PTAA) with small organic molecule additives to optimize energy level structure and charge transport performance. However, these schemes have key shortcomings: the hole mobility of pure organic materials is inherently low, and it is difficult to break through the bottleneck of charge transport efficiency; the synthesis steps of novel organic materials are complicated, the purification is difficult, the commercialization cost is high, and it is difficult to adapt to the needs of large-scale production. Summary of the Invention

[0007] To address the shortcomings of existing hole transport materials in cadmium telluride solar cells, this invention provides an inorganic / organic doped hole transport material. Cadmium telluride solar cells prepared using this material exhibit significantly improved photoelectric conversion efficiency, markedly reduced transport resistance, and effectively improved recombination resistance.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides an inorganic / organic doped hole transport material, comprising an organic matrix and an inorganic dopant phase dispersed in the organic matrix; the amount of the inorganic dopant phase added accounts for 5% to 20% of the total mass of the organic matrix; the inorganic dopant phase is nanoparticles or quantum dots whose surface has been modified by short-chain organic molecules, and the short-chain organic molecules are C2 to C4 straight-chain or branched-chain alkane derivatives containing hydroxyl, thiol or amino groups.

[0009] In a preferred embodiment of the present invention, the amount of the inorganic doped phase added accounts for 10% to 15% of the total mass of the organic matrix.

[0010] In a preferred embodiment of the present invention, the inorganic doped phase is selected from NiO. x At least one of quantum dots, CuI nanoparticles, or CuF nanoparticles.

[0011] In a preferred embodiment of the present invention, the organic matrix is ​​an organic hole transport material.

[0012] In a preferred embodiment of the present invention, the organic hole transport material is Spiro-OMeTAD.

[0013] In a preferred embodiment of the present invention, the short-chain organic molecule is selected from at least one of ethanolamine, ethylene glycol, glycerol, ethylenediamine, ethanethiol, diethanolamine, triethanolamine, and propylene glycol.

[0014] This invention also provides a method for preparing the aforementioned inorganic / organic doped hole transport material, comprising the following steps: Preparation of inorganic doped phase nanoparticles or quantum dots; The inorganic doped phase is surface modified by the short-chain organic molecules. By introducing hydroxyl, thiol or amino functional groups to coordinate / hydrogen bond with the surface of inorganic doped phase nanoparticles or quantum dots, an organic coating layer is formed, which inhibits quantum dot aggregation and improves dispersion stability. Preparation of organic matrix solutions; The surface-modified inorganic doped phase is added to the organic matrix solution in a certain proportion. After dispersion and aging, the inorganic / organic doped hole transport material is obtained.

[0015] In a preferred embodiment of the present invention, the short-chain organic molecule is a C2-C4 straight-chain or branched-chain alkane derivative containing hydroxyl, thiol or amino groups.

[0016] In a preferred embodiment of the present invention, the dispersion is ultrasonic dispersion for 40-50 minutes; the aging is carried out by magnetic stirring at room temperature for 2-3 hours.

[0017] In a preferred embodiment of the present invention, the quantum dots are NiO. x Quantum dots, wherein the inorganic doped phase nanoparticles are CuI nanoparticles or CuF nanoparticles.

[0018] More preferably, the NiO x Quantum dots are prepared according to the following steps: NiO was obtained by hydrothermal reaction using water-soluble nickel salt as raw material and urea as precipitant. x Precursor; The NiO x The precursor is calcined to obtain the NiO. x Quantum dots.

[0019] More preferably, the hydrothermal reaction is carried out at 120°C for 8 hours, and the calcination is carried out at 300°C for 2 hours.

[0020] In a preferred embodiment of the present invention, the surface modification is performed by modifying the inorganic doped phase with ethanolamine or propylene glycol as an improver, and the modification is carried out by stirring at 55~60°C for 4~5 hours.

[0021] The present invention also provides an application of the inorganic / organic doped hole transport material described above in cadmium telluride solar cells.

[0022] The present invention also provides a cadmium telluride solar cell, comprising an electron transport layer, a window layer, a cadmium telluride light absorption layer, a hole transport layer and a back electrode stacked sequentially, wherein the hole transport layer comprises the aforementioned inorganic / organic doped hole transport material.

[0023] In a preferred embodiment of the present invention, the window layer is a CdS layer and the back electrode is an Au electrode.

[0024] In a preferred embodiment of the present invention, the inorganic / organic doped hole transport material is spin-coated onto the surface of a CdTe layer with spin-coating parameters of 4000 r / min and 30 s; then annealed at 120°C for 20 min to form a hole transport layer with a thickness of 80 nm.

[0025] This invention aims to solve the following technical problems through "inorganic / organic doping synergistic design": (1) Solving the problem of low hole transport efficiency in purely inorganic / organic materials: This invention constructs an efficient charge transport channel by precisely selecting inorganic dopant phases and organic matrix, leveraging the high hole mobility of the inorganic phase and the charge transport continuity of the organic phase, thereby reducing carrier recombination losses and improving the photoelectric conversion efficiency of the device.

[0026] (2) Solve the problems of poor interface compatibility and high contact resistance: This invention utilizes the interfacial wettability of the organic matrix and the surface activity of the inorganic phase to form a composite system through doping that forms a tight contact with the CdTe light-absorbing layer, thereby passivating interfacial defects, reducing interfacial contact resistance, and improving carrier extraction efficiency.

[0027] (3) Solve the problem of poor long-term stability of the device: This invention inhibits the oxidative degradation and moisture erosion of the organic matrix through the physical barrier and chemical stabilization effect of the inorganic dopant phase; at the same time, it improves the light resistance and long-term stability of the composite material by leveraging the synergistic effect of the inorganic and organic components.

[0028] (4) Solve the problems of high cost and complex process of existing solutions: This invention selects low-cost, easy-to-prepare inorganic doped phases and organic matrix materials, simplifies the synthesis and doping process, eliminates the need for complex modifications or multilayer structures, reduces the cost of material preparation and device assembly, and meets the needs of large-scale industrial production.

[0029] Compared with the prior art, the present invention has the following advantages: This invention fundamentally solves the core bottlenecks of poor interfacial contact in pure inorganic materials and low charge mobility in pure organic materials through a synergistic design of inorganic and organic doping. The cadmium telluride solar cell prepared using the preferred scheme of this invention (such as Example 1) achieves a photoelectric conversion efficiency (PCE) of up to 8.21%, compared to pure inorganic NiO. x The performance improvement is approximately 135% compared to the comparative example (3.49%), and approximately 116% compared to the pure organic Spiro-OMeTAD comparative example (3.80%). This improvement is the result of simultaneous optimization of three key parameters: open-circuit voltage, short-circuit current density, and fill factor, proving that this approach is a comprehensive and efficient performance optimization strategy. The inorganic / organic doped hole transport material provided by this invention significantly improves the interface characteristics between the hole transport layer and the CdTe light absorption layer. The transmission resistance of the device of this invention is significantly reduced (down to a minimum of 5.9 Ω·cm). -2 This indicates excellent interfacial contact quality and a significant reduction in the charge extraction barrier; simultaneously, the recombination resistance is effectively improved, proving that nonradiative recombination of interfacial charge carriers is effectively suppressed. This characteristic of "low transmission resistance and high recombination resistance" is key to achieving high efficiency.

[0030] The inorganic / organic doped hole transport material provided by this invention not only improves the mobility of the inorganic doped phase, but also provides physical protection for the organic matrix due to its good chemical stability and barrier effect against water and oxygen. This is expected to significantly improve the working stability of the hole transport layer and the entire device under long-term light exposure, high temperature and high humidity environments, and overcome the shortcomings of pure organic materials that are easily oxidized and degraded.

[0031] The inorganic / organic doped hole transport material provided by this invention has a clear preparation route and mild conditions, involving only the synthesis and surface modification of the inorganic phase, and the preparation and blending dispersion of the organic solution. It requires no complex and expensive equipment or stringent process control. All raw materials used are commercially available products, making costs controllable. More importantly, the final doped material can be formed using a mature spin-coating process, which is highly compatible with existing industrial production lines for cadmium telluride solar cells, requiring no large-scale modification of existing equipment, thus greatly facilitating technology transfer and large-scale application.

[0032] The synergistic design strategy of "surface-modified inorganic nanophase + functionalized organic matrix" proposed in this invention has universality. This is achieved by flexibly adjusting the type of inorganic phase (NiO). xBy adjusting the doping ratio (5%~20%) of CuI, CuF, etc., as well as the type of organic matrix, the energy level structure, film formation and interface characteristics of composite materials can be precisely controlled, thereby adapting to CdTe light absorption layers with different compositions or processes. It can even be extended to other photovoltaic device systems such as perovskite solar cells, with a wide range of applications. Attached Figure Description

[0033] Figure 1 These are the electrochemical impedance spectra of the devices used in Examples 1-4 and Comparative Examples 1-2. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain embodiments of the present invention, and should not be construed as limiting the present invention.

[0035] This invention utilizes doping with high-mobility inorganic phases (such as NiO) x A continuous transport network is constructed using quantum dots and CuI nanoparticles; the physical barrier and chemical stability of the inorganic phase are leveraged to enhance device stability; through a synergistic design of inorganic phase energy level calibration and organic phase interface adaptation, the valence band top energy of the composite material is precisely matched to the CdTe layer; furthermore, by flexibly adjusting the type of inorganic phase, doping ratio, and organic matrix type, the requirements of different CdTe light absorption layers can be precisely matched, and this design can be extended to other battery systems, thus broadening its applicability. The specific design is as follows:

[0036] 1) Selection and design of inorganic doped phases: This invention uses NiO x Quantum dots, CuI nanoparticles, and CuF nanoparticles are used as inorganic doping phases. These inorganic materials have advantages such as high hole mobility, strong chemical stability, and great potential for energy level matching with CdTe layers. Quantum dot / nanoparticle morphology features large specific surface area and high surface activity, easily interacting with organic matrices and reducing aggregation. In addition, this invention modifies the surface of the inorganic doping phase by grafting short-chain organic molecules (such as ethanolamine and propylene glycol) to enhance compatibility with organic matrices, while simultaneously regulating surface energy levels to optimize the matching degree with CdTe layers.

[0037] 2) Organic matrix selection and design: This invention selects Spiro-OMeTAD, a commonly used organic hole transport material, as the organic matrix. This organic material has good film-forming properties and interfacial wettability, and can form a tight contact with the CdTe layer; it can be doped with inorganic materials to improve hole transport efficiency, and it is inexpensive and easy to prepare on a large scale.

[0038] 3) Synergistic design of inorganic / organic doping systems: This invention controls the mass ratio of the inorganic dopant phase to the organic matrix at 5-20% (preferably 10-15%). This ratio ensures the high charge transport advantage of the inorganic phase while preventing agglomeration from affecting film formation performance. By adjusting the surface modification degree of the inorganic phase and the molecular structure of the organic matrix, the valence band top energy of the composite system is highly matched with the valence band top energy of the CdTe light-absorbing layer, reducing the hole extraction barrier. The organic matrix provides good interfacial wettability, filling micro-defects on the surface of the CdTe layer; the inorganic dopant phase adheres tightly to the organic matrix, forming continuous charge transport channels, achieving a synergistic effect of "interface adaptation-rapid charge transport".

[0039] The following description is based on specific embodiments.

[0040] Example 1 An inorganic / organic doped hole transport material is prepared according to the following steps: 1) NiO x Quantum dot fabrication: Nickel nitrate (Ni(NO3)2・6H2O, 2 mmol) was dissolved in 50 mL of deionized water and stirred until completely dissolved. Urea (4 mmol) was added as a precipitant, and the mixture was stirred for 30 min before being transferred to a 100 mL hydrothermal reactor. The reactor was heated to 120 °C and reacted at this temperature for 8 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged (8000 r / min, 15 min) to obtain the precipitate. The precipitate was washed three times alternately with deionized water and ethanol, and then dried under vacuum (60 °C, 0.09 MPa) for 12 h to obtain NiO. x Precursor; The precursor was placed in a muffle furnace and calcined at 300℃ for 2 h to obtain NiO with a particle size of 5~8 nm. x Quantum dots.

[0041] 2) NiO x Surface modification of quantum dots: The above NiO x Quantum dots (1 g) were dispersed in 50 mL of ethanol and ultrasonically dispersed for 30 min (300 W). Ethanolamine (0.2 mL) was added as a modifier, and the mixture was stirred at 60 °C for 4 h. After the reaction, the mixture was centrifuged (10000 r / min, 20 min), washed three times with ethanol, and vacuum dried (50 °C, 0.09 MPa) for 8 h to obtain surface-modified NiO. x Quantum dots.

[0042] 0) Preparation of Spiro-OMeTAD solution: Preparation of Spiro-OMeTAD solution: Dissolve 0.1 g of Spiro-OMeTAD powder in 10 mL of anhydrous chlorobenzene, add lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI, 0.02 g) and 4-tert-butylpyridine (TBP, 0.01 mL) as adjuvants, stir at room temperature for 30 min to obtain a homogeneous Spiro-OMeTAD solution with a concentration of 10 mg / mL, seal and protect from light for later use.

[0043] 1) Preparation of inorganic-organic doped hole transport materials Surface-modified NiO x Quantum dots were added to the Spiro-OMeTAD solution at a mass ratio of 12% (relative to the mass of Spiro-OMeTAD), and were first ultrasonically dispersed for 40 min, then magnetically stirred at room temperature for 2 h for aging. Subsequently, the solution was filtered through a 0.22 μm organic phase filter membrane to obtain a uniform, stable, and non-agglomerated inorganic-organic doped hole transport material dispersion.

[0044] Example 2 An inorganic / organic doped hole transport material is prepared according to the following steps: 1) Preparation of CuI nanoparticles: Cuprous iodide powder (CuI, 2 mmol) was dissolved in 40 mL of anhydrous acetonitrile and ultrasonically dispersed for 20 min; polyvinylpyrrolidone (PVP, 0.3 g) was added as a dispersant, and the mixture was stirred for 15 min before being transferred to a 100 mL high-pressure reactor. The temperature was raised to 100 °C and the reaction was carried out at a constant temperature for 6 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged (9000 r / min, 18 min) to collect the precipitate. The precipitate was washed four times with anhydrous ethanol and vacuum dried for 10 h to obtain CuI nanoparticles with a particle size of 8-12 nm.

[0045] 2) Surface modification of CuI nanoparticles: The above CuI nanoparticles (1 g) were dispersed in 50 mL of anhydrous ethanol and ultrasonically dispersed for 30 min; propylene glycol (0.3 mL) was added as a modifier, and the mixture was stirred at 55 °C for 5 h; after the reaction was completed, the mixture was centrifuged (11000 r / min, 22 min), washed 3 times with anhydrous ethanol, and vacuum dried (45 °C, 0.09 MPa) for 9 h to obtain surface-modified CuI nanoparticles. The successful grafting of the modifier was confirmed by FT-IR characterization (the appearance of OH stretching vibration peak).

[0046] 3) Preparation of Spiro-OMeTAD solution: Consistent with Example 1, a homogeneous solution of 10 mg / mL was obtained, which was sealed and protected from light for later use.

[0047] 4) Preparation of inorganic-organic doped hole transport materials: Surface-modified CuI nanoparticles were added to the Spiro-OMeTAD solution at a mass ratio of 10% (relative to the mass of Spiro-OMeTAD), ultrasonically dispersed for 45 min, and then aged by magnetic stirring at room temperature for 2.5 h. After filtration through a 0.22 μm organic phase filter membrane, a uniform and stable dispersion of the doped material was obtained.

[0048] Example 3 An inorganic / organic doped hole transport material is prepared according to the following steps: 1) Preparation of CuF nanoparticles: Copper fluoride (CuF2, 1.5 mmol) and potassium fluoride (KF, 0.8 mmol) were dissolved in 30 mL of deionized water and stirred until completely dissolved. Sodium citrate (0.2 g) was added as a stabilizer to adjust the pH of the solution to 6.5. The mixture was transferred to a 100 mL hydrothermal reactor, heated to 130 °C, and reacted at a constant temperature for 7 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged (10,000 r / min, 20 min) to collect the precipitate. The precipitate was washed three times alternately with deionized water and anhydrous ethanol and dried under vacuum for 12 h to obtain CuF2 nanoparticles with a particle size of 6–10 nm.

[0049] 2) Surface modification of CuF nanoparticles: The above CuF nanoparticles (1 g) were dispersed in 50 mL of anhydrous ethanol and ultrasonically dispersed for 35 min; ethanolamine (0.25 mL) was added as a modifier, and the mixture was stirred at 60 °C for 4.5 h; after the reaction was completed, the mixture was centrifuged (12000 r / min, 25 min), washed 4 times with anhydrous ethanol, and vacuum dried for 8 h to obtain surface-modified CuF nanoparticles.

[0050] 3) Preparation of Spiro-OMeTAD solution Consistent with Example 1, a homogeneous solution of 10 mg / mL was obtained, which was sealed and protected from light for later use.

[0051] 4) Preparation of inorganic-organic doped hole transport materials: Surface-modified CuF nanoparticles were added to the Spiro-OMeTAD solution at a mass ratio of 15% (relative to the mass of Spiro-OMeTAD), ultrasonically dispersed for 50 min, and then aged by magnetic stirring at room temperature for 3 h. After filtration through a 0.22 μm organic phase filter membrane, a uniform and stable dispersion of the doped material was obtained.

[0052] Example 4 An inorganic / organic doped hole transport material is prepared according to the following steps: Surface-modified CuF nanoparticles were added to the Spiro-OMeTAD solution at a mass ratio of 10% (relative to the mass of Spiro-OMeTAD), with the remainder being the same as in Example 3.

[0053] Example 5 An inorganic / organic doped hole transport material is prepared according to the following steps: Surface-modified NiO x Quantum dots were added to the Spiro-OMeTAD solution at a mass ratio of 5% (relative to the mass of Spiro-OMeTAD), with the remainder being the same as in Example 1.

[0054] Example 6 An inorganic / organic doped hole transport material is prepared according to the following steps: Surface-modified NiO x Quantum dots were added to the Spiro-OMeTAD solution at a mass ratio of 20% (relative to the mass of Spiro-OMeTAD), with the remainder being the same as in Example 1.

[0055] Application Example 1 A cadmium telluride solar cell was fabricated using an inorganic / organic doped hole transport material. The device structure is: ITO / ZnO (electron transport layer) / CdS (window layer) / CdTe (light absorption layer) / hole transport layer (the material of this invention) / Au (back electrode). The specific fabrication steps are as follows: 1) ITO pretreatment: The ITO substrate was ultrasonically cleaned with deionized water, ethanol and acetone for 15 min each to remove surface oil and impurities; after drying at 100℃ for 15 min, it was placed in a UV ozone generator for 25 min to improve surface hydrophilicity and was ready for use.

[0056] 2) Preparation of electron transport layer (ZnO): ZnO nanoparticle dispersion (5% solid content) was spin-coated onto the pretreated ITO surface. Spin-coating parameters: 3000 r / min rotation speed, 30 s time; then annealed at 150℃ for 30 min to form a ZnO electron transport layer with a thickness of about 50 nm.

[0057] 3) Preparation of window layer (CdS): A CdS window layer was deposited on the ZnO layer using chemical bath deposition (CBD): The substrate was immersed in an aqueous solution containing CdCl2 (0.05 mol / L) and thiourea (0.1 mol / L) and reacted at 70℃ for 20 min; after the reaction, it was washed 3 times with deionized water and dried at 100℃ for 10 min to form a CdS window layer with a thickness of about 50 nm.

[0058] 4) Preparation of light-absorbing layer (CdTe): CdTe light-absorbing layer was deposited on CdS layer using near-space sublimation (CSS) method: CdTe powder (purity 99.99%) was used as source material, the substrate temperature was controlled at 350℃, the source temperature was controlled at 600℃, the deposition time was 30 min, and a p-type CdTe light-absorbing layer with a thickness of about 2 μm was formed.

[0059] 5) Preparation of hole transport layer (material of the present invention): The inorganic / organic doped hole transport material dispersion of Example 1 of the present invention was spin-coated on the surface of CdTe layer. Spin-coating parameters: rotation speed 4000 r / min, time 30 s; then annealed at 120℃ for 20 min to form a hole transport layer with a thickness of about 80 nm.

[0060] 6) Back electrode (Au) fabrication: The substrate is transferred to a vacuum evaporator, and the deposition is carried out under a vacuum of ≤5×10⁻⁶. -4 Under the condition of Pa, a thin Au film (approximately 100 nm thick, deposition rate 0.2 nm / s) was deposited to obtain a complete cadmium telluride solar cell device.

[0061] Application Example 2 The hole transport layer uses the material from Example 2 as the hole transport layer, and the remaining preparation steps are the same as in Application Example 1.

[0062] Application Example 3 The hole transport layer uses the material from Example 3 as the hole transport layer, and the remaining preparation steps are the same as in Application Example 1.

[0063] Application Example 4 The hole transport layer uses the material from Example 4 as the hole transport layer, and the remaining preparation steps are the same as in Application Example 1.

[0064] Application Example 5 The hole transport layer uses the material from Example 5 as the hole transport layer, and the remaining preparation steps are the same as in Application Example 1.

[0065] Application Example 6 The hole transport layer uses the material from Example 6 as the hole transport layer, and the remaining preparation steps are the same as in Application Example 1.

[0066] Comparative Example 1 The hole transport layer uses pure inorganic materials (NiO). x As a hole transport layer, the remaining preparation steps are the same as in Application Example 1.

[0067] Comparative Example 2 The hole transport layer uses a pure organic material (Spiro-OMeTAD) as the hole transport layer, and the remaining preparation steps are the same as in Application Example 1.

[0068] Performance tests were conducted on the devices used in Application Examples 1-6 and Comparative Examples 1-2. Test conditions: AM 1.5G simulated sunlight, light intensity 100 mW·cm². -2 The room temperature was 25℃ and the humidity was 25% RH. The results are shown in Tables 1 and 2.

[0069] Table 1. Device performance test results of Application Examples 1-4 and Comparative Examples 1-2 As shown in Table 1, this invention achieves a significant improvement in photoelectric conversion efficiency through inorganic / organic doping synergistic design. The highest photoelectric conversion efficiency of the device exceeds 8%, which is 135% higher than that of pure inorganic materials (3.49%) and 116% higher than that of pure organic materials (3.80%). This is due to the synergistic design improving energy level matching and interface contact, which simultaneously improves open-circuit voltage, short-circuit current density and fill factor.

[0070] Table 2. Electrochemical Impedance Spectroscopy Results As shown in Table 2, the Rs values ​​of all inorganic / organic doped systems (Application Examples 1-6) are significantly lower than those of pure inorganic or pure organic systems (Comparative Examples 1 and 2), indicating that the doping design greatly improves the interfacial contact quality between the hole transport layer and the CdTe light-absorbing layer, and reduces the charge extraction barrier. Meanwhile, the Rct values ​​of the doped systems are generally higher than those of the comparative examples, indicating that nonradiative recombination of charge carriers is effectively suppressed, and the recombination centers at the interface and in the bulk phase are passivated.

[0071] Depend on Figure 1 Furthermore, it can be seen that the doping synergistic design strategy of "surface-modified inorganic phase + functionalized organic matrix" can form a close contact with the CdTe light absorption layer, passivate interface defects, improve transmission resistance, and reduce interface contact resistance, thereby improving carrier extraction efficiency and realizing three-dimensional synergistic optimization of "energy level matching-charge transport-interface stability", breaking through the performance bottleneck of pure inorganic / organic materials.

[0072] The inorganic / organic doped hole transport material provided by this invention has a simple preparation process and obvious cost advantages: the material preparation only requires four core processes, without the need for complex equipment and harsh reaction conditions; all raw materials used are commercially available low-cost materials, and the device preparation process is compatible with existing cadmium telluride industrial production lines, without the need for large-scale equipment modification, and has a wide range of applications and strong scalability.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An inorganic / organic doped hole transport material, characterized in that, It includes an organic matrix and an inorganic dopant phase dispersed in the organic matrix; the amount of the inorganic dopant phase added accounts for 5% to 20% of the total mass of the organic matrix; the inorganic dopant phase is nanoparticles or quantum dots whose surface has been modified by short-chain organic molecules, and the short-chain organic molecules are C2 to C4 straight-chain or branched-chain alkane derivatives containing hydroxyl, thiol or amino groups.

2. The inorganic / organic doped hole transport material according to claim 1, characterized in that, The amount of the inorganic dopant phase added accounts for 10% to 15% of the total mass of the organic matrix.

3. The inorganic / organic doped hole transport material according to claim 1 or 2, characterized in that, The inorganic doping phase is selected from NiO. x At least one of quantum dots, CuI nanoparticles, or CuF nanoparticles.

4. The inorganic / organic doped hole transport material according to claim 1 or 2, characterized in that, The organic matrix is ​​the organic hole transport material Spiro-OMeTAD.

5. The inorganic / organic doped hole transport material according to claim 1, characterized in that, The short-chain organic molecule is selected from at least one of ethanolamine, ethylene glycol, glycerol, ethylenediamine, ethanethiol, diethanolamine, triethanolamine, and propylene glycol.

6. A method for preparing an inorganic / organic doped hole transport material according to any one of claims 1 to 5, characterized in that, Includes the following steps: Preparation of inorganic doped phase nanoparticles or quantum dots; The inorganic doped phase is surface modified using the short-chain organic molecules; the short-chain organic molecules are C2-C4 straight-chain or branched-chain alkane derivatives containing hydroxyl, thiol, or amino groups. Preparation of organic matrix solutions; The surface-modified inorganic doped phase is added to the organic matrix solution in a certain proportion. After dispersion and aging, the inorganic / organic doped hole transport material is obtained.

7. The preparation method according to claim 6, characterized in that, The dispersion is performed by ultrasonic dispersion for 40-50 minutes; the aging is carried out by magnetic stirring at room temperature for 2-3 hours.

8. The application of any one of the inorganic / organic doped hole transport materials according to claims 1 to 5 in cadmium telluride solar cells.

9. A cadmium telluride solar cell, comprising an electron transport layer, a window layer, a cadmium telluride light-absorbing layer, a hole transport layer, and a back electrode stacked sequentially, characterized in that, The hole transport layer comprises an inorganic / organic doped hole transport material as described in any one of claims 1 to 5.

10. The cadmium telluride solar cell according to claim 9, characterized in that, The window layer is a CdS layer, and the back electrode is an Au electrode.

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