Trans-wide-band-gap perovskite solar cell capable of effectively releasing residual stress passivation and preparation method of trans-wide-band-gap perovskite solar cell
By doping ANdPy additives in the active layer of perovskite solar cells, the photophase separation and open-circuit voltage loss problems occurring in wide-bandgap perovskite solar cells at high Br content, and the instability caused by residual stress in perovskite films are solved, thereby achieving improvements in efficiency and stability.
Patent Information
- Application Number
- CN202411922725.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-03-28
AI Technical Summary
Wide-bandgap perovskite solar cells are prone to photophase separation and open-circuit voltage loss at high Br content, and residual stress in perovskite films leads to device instability.
The formation of large-sized grains is promoted by doping the N,N-dimethyl-2 sulfamoyl nicotinamide (ANdPy) additive in the perovskite active layer.
It effectively improves the efficiency and stability of solar cells, improves the power conversion efficiency (PCE) from 16.63% to 18.39%, and reduces residual stress.
Smart Images
Figure CN119730549A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of solar cells, and in particular relates to an inverted wide bandgap perovskite solar cell that effectively releases residual stress passivation and a preparation method thereof. Background Art
[0002] Organic-inorganic metal halide perovskite materials have become the most popular photovoltaic materials in the past decade due to their unprecedented development of power conversion efficiency (PCE), which has increased from 3.8% in the first report to 26.7% in the recently certified single-junction device. Perovskites have many attractive features including their superior properties such as high absorption coefficient, excellent defect tolerance, long carrier lifetime, diffusion length and low exciton binding energy. However, the Shockley-Quisser (SQ) limit restricts the PCE of single-junction cells, and stacking multiple absorber layers with complementary bandgaps to make tandem solar cells is a proven solution to surpass the SQ limit. Perovskite materials are ideal for making tandem solar cells due to their tunable bandgaps. Wide-bandgap perovskite solar cells are often used as the top subcell in perovskite-based tandem photovoltaic cells, which play a key role in minimizing the thermalization loss of high-energy photons and ensuring consistent performance of tandem devices by preventing excessive radiative UV light from reaching the bottom cell.
[0003] For wide bandgap perovskite solar cells, when the Br content is too high, serious photoinduced phase separation and large open circuit voltage loss of the device will occur. As early as 2015, Hoke et al. discovered the phenomenon of photoinduced phase separation in mixed halogen perovskites. When the Br content in the perovskite is greater than 20%, the Br / I mixed perovskite film tends to separate into Br-rich and I-rich regions under light. The formed I-rich phase has a lower band gap than the initial uniform mixed phase, which gives the charge a driving force to converge to the I-rich region, and captures holes in the I-rich region to form a carrier recombination center, affecting the performance of the device.
[0004] In addition, studies have shown that the escape of volatile organic cations during the continuous thermal annealing of perovskite films leads to a stoichiometric mismatch in the perovskite ratio composition. In addition, due to the vertical temperature gradient, the perovskite film undergoes inconsistent thermal expansion and cooling contraction, resulting in significant residual stress. Therefore, residual stress is an important intrinsic source of instability in perovskite films, and eliminating residual stress in perovskite films is of great significance to improving the stability of photovoltaic cells and promoting their commercialization. For perovskite structures with different compositions, there are many methods to eliminate residual stress, which can generally be divided into four categories: 1) eliminating the temperature difference in the vertical direction of the perovskite film; 2) inhibiting the escape of volatile organic cations or compensating cations; 3) using plastic substrates or interface modification layers with thermal expansion coefficients similar to those of perovskites to reduce thermal expansion mismatch; 4) strain compensation strategies. However, to the best of our knowledge, in the past few years, there have been few studies on releasing residual stress in formamidinium cesium (FACs) PSCs by additive engineering. In addition, the optical trapping performance of the devices is still limited by excessive carrier recombination, and the performance of the best devices is also affected by excessive open-circuit voltage (Voc) losses and relatively low fill factor (FF). Therefore, it is imperative to improve the efficiency and stability of PSCs by regulating the carrier dynamics of perovskite films and releasing residual stress. Summary of the invention
[0005] The purpose of the present invention is to provide an inverted wide-bandgap perovskite solar cell that effectively releases residual stress passivation, passivates internal defects of the perovskite active layer and releases residual stress inside the perovskite by doping, promotes the preparation of perovskite films with large-sized grains, and thus improves device efficiency and stability.
[0006] Another object of the present invention is to provide a method for preparing the inverted wide bandgap perovskite solar cell that effectively releases residual stress passivation.
[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:
[0008] An inverted wide bandgap perovskite solar cell with effective doping release of residual stress passivation is composed of a glass substrate, a transparent conductive oxide, a hole transport layer, an organic-inorganic hybrid perovskite active layer, an intermediate insertion layer, an electron transport layer, a hole blocking layer and a metal electrode from bottom to top, wherein the organic-inorganic hybrid perovskite active layer is composed of Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 ; The organic-inorganic hybrid perovskite active layer is also doped with N,N-dimethyl-2-sulfamoylnicotinamide (ANdPy) additive.
[0009] In some specific embodiments, the molar percentage of the ANdPy additive incorporated into the organic-inorganic hybrid perovskite active layer is 0.2%-0.5%, preferably 0.3%, based on the molar amount of the organic-inorganic hybrid perovskite active layer.
[0010] In some specific embodiments, the transparent conductive oxide is ITO, which together with the glass substrate is the etched ITO conductive glass commonly used in the art.
[0011] In some specific embodiments, the hole transport layer is [4-(7H-dibenzo[c,g]carbazole-7-yl)butyl]phosphoric acid (4PADCB) and has a thickness of 10-30 nm, preferably 20 nm.
[0012] In some specific embodiments, the intermediate insertion layer is LiF, and has a thickness of 1-3 nm, preferably 2 nm.
[0013] In some specific embodiments, the electron transport layer is C60, and has a thickness of 20-30 nm, preferably 25 nm.
[0014] In some specific embodiments, the hole blocking layer is BCP with a thickness of 5-7 nm, preferably 6 nm.
[0015] In some specific embodiments, the metal electrode is Ag or Cu, and has a thickness of 90-110 nm, preferably 100 nm.
[0016] On the other hand, the method for preparing the above-mentioned inverted wide bandgap perovskite solar cell comprises the following steps:
[0017] 1) Cleaning the conductive glass substrate;
[0018] 2) preparing a hole transport layer;
[0019] 3) Cs0.2FA0.8PbI1.8Br1.2 perovskite precursor powder and ANdPy are dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and a perovskite active layer is prepared by spin coating;
[0020] 4) An intermediate insertion layer, an electron transport layer, a hole blocking layer and a metal electrode are sequentially prepared on the perovskite active layer.
[0021] In some specific implementation schemes, the specific process of step 4) is: using vacuum evaporation method to sequentially prepare the intermediate insertion layer, the electron transport layer, the hole blocking layer and the metal electrode.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] The present invention passivates the internal defects of the perovskite active layer and releases the residual stress inside the perovskite by doping, promotes the preparation of perovskite thin films with large-sized grains, and improves the efficiency and stability of the device. In particular, ANdPy as a dopant plays a significant role in the stress release inside the perovskite layer, and can increase the efficiency of the inverted wide-bandgap perovskite solar cell from 16.63% to 18.39%.
[0024] The inferred mechanism of the present invention is that during the continuous thermal annealing process of the perovskite film, the escape of volatile organic cations leads to a stoichiometric mismatch in the perovskite ratio composition. Due to the vertical temperature gradient, the perovskite film undergoes inconsistent thermal expansion and cooling contraction, resulting in significant residual stress, which is an important intrinsic source of instability of the perovskite film. The ethylamine group in the doped additive ANdPy can form a hydrogen bond with FAI, and O=S=O can coordinate with Pb2+ in PbI2 to form an O=S=O·Pb chelate, which interacts with the hydrogen bond to lead to faster α-FAPbI3 nucleation without the contribution of the yellow δ phase, thereby enhancing the crystallization of the polycrystalline film and forming a film with a larger grain size and a preferred (100) orientation, which effectively reduces the residual tensile stress. In addition, C=O can also coordinate with Pb2+ to passivate deep defects and improve device performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is a schematic diagram of the structure of an inverted wide-bandgap perovskite solar cell of the present invention.
[0026] Figure 2 Scanning electron microscope images of the perovskite active layer interface of Comparative Example 1 (left) and Example 1 (right) of the present invention.
[0027] Figure 3 The GIXRD spectra of Comparative Example 1 (left) and Example 1 (right) of the present invention are shown.
[0028] Figure 4 It is the linear fitting diagram of residual stress of comparative example 1 (control) and embodiment 1 (target) of the present invention.
[0029] Figure 5 These are the JV curves of comparative example 1 (control) and example 1 (target) of the present invention. DETAILED DESCRIPTION
[0030] In order to make the technical problem, technical solution and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to explain the present invention and is not used to limit the present invention.
[0031] An inverted wide bandgap perovskite solar cell, with reference to the attached Figure 1 As shown, it consists of a glass substrate, a transparent conductive oxide, a hole transport layer, an organic-inorganic hybrid perovskite active layer, an intermediate insertion layer, an electron transport layer, a hole blocking layer and a metal electrode.
[0032] The perovskite active layer is added with a molar percentage of 0.2%-0.5% N,N-dimethyl-2-sulfamoylnicotinamide (ANdPy), such as 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc., preferably 0.3%.
[0033] The present invention adds ANdPy additives to the perovskite active layer by doping, which can effectively release the residual stress in the perovskite layer. During the continuous thermal annealing process of the perovskite film, the escape of volatile organic cations leads to a stoichiometric mismatch in the perovskite ratio composition. Due to the vertical temperature gradient, the perovskite film undergoes inconsistent thermal expansion and cooling contraction, resulting in significant residual stress, which is an important intrinsic source of instability of the perovskite film. The ethylamine group in the doped additive ANdPy can form a hydrogen bond with FAI, and O=S=O can coordinate with Pb2+ in PbI2 to form a chelation effect, which interacts with the hydrogen bond to lead to faster α-FAPbI3 nucleation without the contribution of the yellow δ phase, thereby enhancing the crystallization of the polycrystalline film, forming a film with a larger grain size and a preferred (100) orientation, and effectively reducing the residual tensile stress. In addition, C=O can also coordinate with Pb2+ to passivate deep defects and improve device performance.
[0034] The key to the present invention is to add ANdPy as a dopant in the perovskite active layer, and other structures can refer to the prior art, such as glass substrate, transparent conductive oxide, hole transport layer, intermediate insertion layer, electron transport layer, hole blocking layer and metal electrode, etc., can all refer to the prior art. Among them, the organic-inorganic hybrid perovskite active layer component is Cs0.2FA0.8PbI1.8Br1.2, which can also be prepared by referring to the method of the prior art.
[0035] The present invention also provides a method for preparing the above-mentioned inverted wide bandgap perovskite solar cell, comprising the following steps:
[0036] 1) Perform UV ozone cleaning on the transparent conductive substrate;
[0037] 2) preparing a hole transport layer;
[0038] 3) Cs 0.2 FA 0.8 PbI 1.8 Br 1.2The perovskite precursor powder and ANdPy powder were dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and the perovskite active layer was prepared by spin coating;
[0039] 4) preparing an intermediate insertion layer, an electron transport layer, a hole blocking layer and a metal electrode in sequence, for example, by using a vacuum evaporation method to prepare the intermediate insertion layer, the electron transport layer, the hole blocking layer and the metal electrode in sequence.
[0040] The present invention is further explained below by more specific examples, but does not constitute any limitation.
[0041] Example 1
[0042] The glass substrate etched with ITO had a size of 2.5 cm×2.5 cm and was treated with UV ozone for 15 minutes before use.
[0043] In a glove box filled with nitrogen (H2O < 0.01 ppm, O2 < 0.01 ppm), 50 μl of 4PADCB hole transport layer solution was dropped onto the glass substrate, and then spin-coated at a speed of 3000 rpm and an acceleration of 1200 rpm / s for 30 s, and then the film was annealed on a hot stage at 100 °C for 5 min.
[0044] Then, 50 μl of the perovskite precursor solution was dropped onto the glass substrate, and the substrate was spin-coated at 500 rpm and 100 rpm / s for 2 s, 4000 rpm and 1500 rpm / s for 60 s, and 150 μl of chlorobenzene was added at the countdown of 35 s. The spin-coated perovskite film was annealed at 65°C for 5 min and 100°C for 15 min on a hot plate in a glove box.
[0045] The hole transport layer was prepared by adding 0.5 mg of 4PADCB powder into 1 ml of ethanol (C2H5OH) and shaking for 5 min before use. 0.2 FA 0.8 PbI 1.8 Br 1.2 The perovskite precursor solution was prepared by dissolving FABr (60 mg, 0.48 mmol), CsI (62.35 mg, 0.24 mmol), FAI (82.55 mg, 0.48 mmol), PbBr2 (176.16 mg, 0.48 mmol), PbI2 (331.92 mg, 0.72 mmol) and 0.75 mg ANdPy in 0.25 ml of DMSO and 0.75 ml of DMF to prepare a 1.2 M solution. The prepared precursor was shaken in an oscillator for 5 min before use.
[0046] The annealed perovskite film was then moved to the evaporation glove box, and the intermediate insertion layer LiF
[0047] (2nm), electron transport layer C 60 (25nm), hole blocking layer BCP (6nm), metal electrode Ag (100nm).
[0048] Example 2
[0049] Example 1 was repeated, and the concentration of ANdPy in the perovskite active layer was 0.25 mol %.
[0050] Example 3
[0051] Example 1 was repeated, and the concentration of ANdPy in the perovskite active layer was 0.20 mol %.
[0052] Comparative Example 1
[0053] Example 1 was repeated without adding ANdPy to the perovskite active layer.
[0054] The open circuit voltage (V) of the forward scan and reverse scan of Examples 1-3 and Comparative Example 1 oc ), short circuit current (J sc ), fill factor (FF), and power conversion efficiency (PCE), as shown in Table 1.
[0055] Table 1
[0056]
[0057] As shown in the table above, when the molar mass ratio of ANdPy added to the perovskite active layer is 0.30%, the pore size is 0.09 cm 2 The best efficiency under the template is 18.39%. Compared with the comparative example, V oc , J sc , FF increased significantly.
[0058] Figure 2 Scanning electron microscope images of the perovskite active layer interface of Comparative Example 1 (left) and Example 1 (right) are shown. It can be seen that compared with the comparative example, the grain size formed by the perovskite film shown in the example is larger and more uniform. Figure 3 The GIXRD patterns of Comparative Example 1 and Example 1 are shown. The linear relationship of is fitted, and the slope of the fitting curve is positive. Figure 4 , indicating that the perovskite film has compressive stress. Compared with the control perovskite film, the residual stress in the modified perovskite film is reduced from 24MPa to 20MPa, a decrease of about 16.6%. Figure 5The JV curves of Comparative Example 1 and Example 1 are shown, and it can be seen that the voltage and current of the example are significantly improved.
[0059] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. An inverted wide bandgap perovskite solar cell with effective doping to release residual stress passivation, characterized in that: From bottom to top, it is composed of a glass substrate, a transparent conductive oxide, a hole transport layer, an organic-inorganic hybrid perovskite active layer, an intermediate insertion layer, an electron transport layer, a hole blocking layer and a metal electrode, wherein the organic-inorganic hybrid perovskite active layer is composed of Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 ; The organic-inorganic hybrid perovskite active layer is also doped with N,N-dimethyl-2-sulfamoylnicotinamide (ANdPy) additive.
2. The inverted wide bandgap perovskite solar cell according to claim 1, characterized in that: The molar percentage of the ANdPy additive doped into the organic-inorganic hybrid perovskite active layer is 0.2%-0.5%, preferably 0.3%, based on the molar amount of the organic-inorganic hybrid perovskite active layer.
3. The inverted wide bandgap perovskite solar cell according to claim 1, characterized in that: The transparent conductive oxide is ITO.
4. The inverted wide bandgap perovskite solar cell according to claim 1, characterized in that: The hole transport layer is 4PADCB and has a thickness of 10-30 nm.
5. The inverted wide bandgap perovskite solar cell according to claim 1, characterized in that: The intermediate insertion layer is LiF, and has a thickness of 1-3 nm.
6. The inverted wide bandgap perovskite solar cell according to claim 1, characterized in that: The electron transport layer is C 60 , thickness is 20-30nm.
7. The inverted wide bandgap perovskite solar cell according to claim 1, characterized in that: The hole blocking layer is BCP, and has a thickness of 5-7 nm.
8. The inverted wide bandgap perovskite solar cell according to claim 1, characterized in that: The metal electrode is Ag or Cu, and has a thickness of 90-110 nm.
9. The method for preparing an inverted wide bandgap perovskite solar cell according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) Cleaning the conductive glass substrate; 2) preparing a hole transport layer; 3) Cs 0.2 FA 0.8 PbI 1.8 Br 1.2 The perovskite precursor powder and ANdPy were dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and the perovskite active layer was prepared by spin coating; 4) An intermediate insertion layer, an electron transport layer, a hole blocking layer and a metal electrode are sequentially prepared on the perovskite active layer.
10. The preparation method according to claim 9, characterized in that: Step 4) The intermediate insertion layer, the electron transport layer, the hole blocking layer and the metal electrode are prepared in sequence by vacuum evaporation.