Trans-perovskite solar cell and preparation method thereof

Abstract

The invention relates to the technical field of perovskite solar cells, in particular to a trans-perovskite solar cell and a preparation method thereof. An interface modification layer is arranged between a perovskite light absorption layer and an electron transport layer of the trans-perovskite solar cell, and the interface modification layer is made of guanfacine hydrochloride molecules. By utilizing the molecular structure characteristic of guanfacine hydrochloride, the interface transmission efficiency between the perovskite material and the charge transmission layer can be improved, and the device performance and the environmental stability are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and specifically to a reverse perovskite solar cell and a preparation method thereof. Background Art

[0002] Perovskite solar cells (PSCs) have become a research hotspot in the photovoltaic field due to their high power conversion efficiency (PCE) and low-cost manufacturing process. However, the commercial application of conventional bandgap perovskite solar cells still faces the following core challenges:

[0003] Interface defects and energy level mismatch: There are a large number of uncoordinated Pb 2 , I 2+ , vacancies and chemical impurities (such as PbI - ) at the interface between the perovskite and the charge transport layer (such as SnO 2 ), Spiro-OMeTAD), resulting in increased carrier recombination and significant decreases in the fill factor and open-circuit voltage.

[0004] Interface ion diffusion and phase separation: Under the action of light, humidity or electric field, ion migration and phase change are likely to occur at the perovskite interface, accelerating the decay of device performance.

[0005] Limitations of traditional interface modifiers: Existing technologies mostly use two-dimensional perovskite layers (such as PEA 2 PbI 4 ) or metal-organic frameworks (MOF) to modify the interface. Although they can partially passivate defects, there are problems such as complex processes, insufficient material stability or only targeting single-type defects.

[0006] Therefore, improving the interface transfer efficiency between the perovskite material and the charge transport layer while enhancing the environmental stability of the device is a key problem that needs to be solved urgently in the field of perovskite solar cells. Summary of the Invention

[0007] In order to solve the defects existing in the prior art, the present invention provides a reverse perovskite solar cell and a preparation method thereof, which can improve the interface transfer efficiency between the perovskite material and the charge transport layer, thereby improving the device performance and environmental stability.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a reverse perovskite solar cell, wherein an interface modification layer is provided between the perovskite light-absorbing layer and the electron transport layer of the reverse perovskite solar cell, and the material of the interface modification layer is guanfacine hydrochloride molecules.

[0010] Preferably, the concentration of the guanfacine hydrochloride molecules is 0.5 - 4 mg / ml.

[0011] Preferably, the concentration of the guanfacine hydrochloride molecules is 1 to 4 mg / ml.

[0012] Preferably, the concentration of the guanfacine hydrochloride molecules is 1 to 2 mg / ml.

[0013] Preferably, the interface modification layer is prepared by spin-coating a guanfacine hydrochloride solution on the perovskite light-absorbing layer and then annealing.

[0014] Preferably, the inverted perovskite solar cell further includes a conductive glass, a hole transport layer, and a metal electrode.

[0015] Preferably, the material of the hole transport layer is selected from any one or more of Meo-2PACz (methoxy-substituted diphenylcarbazole), Me-4PACz ((4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid), and Me-2PACz ([2-(3,6-diphenyl-9H-carbazol-9-yl)ethyl]phosphonic acid).

[0016] The material of the perovskite light-absorbing layer in the present invention adopts a material with the ABX 3 structure, wherein A is a monovalent or divalent cation, including but not limited to Ca 2+ 、Sr 2+ 、formamidine HN=CHNH 3 + (FA), methylamine CH 3 NH 3 + (MA) or a combination thereof; B is a trivalent or tetravalent transition metal cation, including but not limited to Ti 4+ 、Pb 2+ 、Sn 2+ or a combination thereof; X is an anion, including but not limited to O 2- 、Cl-, Br-, I- or a combination thereof.

[0017] Preferably, the material of the electron transport layer is selected from any one or more of PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), BCP (bathocuproine), and C60.

[0018] Preferably, the material of the metal electrode is selected from any one or more of gold, silver, aluminum, and copper.

[0019] In a second aspect, the present invention provides a method for preparing an inverted perovskite solar cell, including preparing an interface modification layer between a perovskite light-absorbing layer and an electron transport layer, and the material of the interface modification layer is guanfacine hydrochloride molecules.

[0020] Preferably, the concentration of the guanfacine hydrochloride molecule is 0.5 - 4 mg / ml.

[0021] Preferably, the concentration of the guanfacine hydrochloride molecule is 1 - 4 mg / ml.

[0022] Preferably, the concentration of the guanfacine hydrochloride molecule is 1 - 2 mg / ml.

[0023] Preferably, the method for preparing the interfacial modification layer is: spin-coating a guanfacine hydrochloride solution on the perovskite light-absorbing layer and annealing to obtain it.

[0024] Preferably, the preparation method further includes cleaning the conductive glass, preparing the hole transport layer, preparing the perovskite light-absorbing layer, preparing the electron transport layer, and preparing the metal electrode.

[0025] The beneficial effects of the present invention are:

[0026] The present invention creatively uses the drug molecule guanfacine hydrochloride molecule as a perovskite interfacial modifier. As an approved drug, this molecule has both low toxicity and a mature synthesis process, perfectly meeting the green development requirements of photovoltaic materials. Through the hydrogen bond interaction between the N-H of the guanidine group in its molecular structure and the halogen ions (I- / Br-) on the perovskite surface, it effectively passivates interface defects and inhibits ion migration; at the same time, the methoxy group in the molecule optimizes the perovskite surface energy level through the electron-donating effect, improves the energy level matching with the charge transport layer, reduces the interface barrier, and effectively improves the photoelectric conversion efficiency and stability.

[0027] The present invention proposes a preparation method for a reverse perovskite solar cell, which has the characteristics of simple process and accessible raw materials. By optimizing the preparation process flow, a perovskite solar cell device with excellent photoelectric performance and stability has been successfully prepared. The present invention provides an important theoretical basis and practical guidance for promoting the green scale development and commercial application of perovskite photovoltaic technology, and lays a solid foundation for further exploring efficient, stable, and low-cost perovskite photovoltaic devices. Description of the Drawings

[0028] Figure 1 It is the J-V curve diagram of the perovskite solar cell devices prepared in Examples 1 - 4 and Comparative Example 1.

[0029] Figure 2 It is the efficiency diagram of the perovskite solar cell devices prepared in Examples 1 - 4 and Comparative Example 1.

[0030] Figure 3 It is the stability test diagram of the perovskite solar cell devices prepared in Example 3 and Comparative Example 1.

[0031] Figure 4XRD patterns of the interfacial modification layer prepared in Example 3 and the perovskite light-absorbing layer prepared in Comparative Example 1.

[0032] Figure 5 SEM images of the interfacial modification layer prepared in Example 3 and the perovskite light-absorbing layer prepared in Comparative Example 1.

[0033] Figure 6 Cyclic voltammogram (left) and electrochemical impedance spectroscopy (right) of the perovskite solar cell devices prepared in Example 3 and Comparative Example 1. Detailed Description of the Invention

[0034] In order to enable those skilled in the art to better understand the technical solutions of the invention, the present invention will be further described in detail below in conjunction with the specific embodiments.

[0035] To solve the problem of the interfacial transport efficiency between the perovskite material and the charge transport layer in perovskite solar cells, the present invention first provides a reverse perovskite solar cell. An interfacial modification layer is provided between the perovskite light-absorbing layer and the electron transport layer of the reverse perovskite solar cell, and the material of the interfacial modification layer is guanfacine hydrochloride molecule.

[0036] The guanfacine hydrochloride molecule of the present invention, also known as guanfacine hydrochloride, C 9 H 10 Cl 3 N 3 O, is a clinically approved drug molecule with low biological toxicity and a mature industrial synthesis route, which conforms to the development trend of green chemistry.

[0037] Adding guanfacine hydrochloride molecule as the interfacial modification layer material between the perovskite light-absorbing layer and the electron transport layer in the present invention has the following advantages. On the one hand, the N-H in the guanidine group of this molecule can form hydrogen bonds with I- or Br- on the surface of the perovskite, enhancing the interfacial stability and inhibiting ion migration. On the other hand, the electron-donating effect of the methoxy group in this molecule may fine-tune the surface energy level of the perovskite, improve the energy level matching with the charge transport layer, and reduce the interfacial barrier, thereby further stabilizing the perovskite crystal structure and enhancing the overall performance of the device. The above effects are combined to achieve the purpose of a molecule using different mechanisms to multi-dimensionally improve the structural stability of the perovskite material, thereby significantly enhancing the comprehensive performance and long-term operation reliability of the device.

[0038] Preferably, the concentration of guanfacine hydrochloride molecules is 0.5 - 4 mg / ml. Exemplarily, the concentration of guanfacine hydrochloride molecules is any one of 0.5 mg / ml, 1 mg / ml, 2 mg / ml, 4 mg / ml or a value between any two of them. Preferably, the concentration of guanfacine hydrochloride molecules is 1 - 4 mg / ml. Preferably, the concentration of guanfacine hydrochloride molecules is 1 - 2 mg / ml.

[0039] The preparation method of the interface modification layer in the present invention is as follows: spin-coat a guanfacine hydrochloride solution on the perovskite light-absorbing layer and then anneal to obtain it.

[0040] The inverted perovskite solar cell of the present invention further includes a conductive glass, a hole transport layer and a metal electrode.

[0041] The material of the hole transport layer in the present invention is selected from any one or more of Meo-2PACz (methoxy-substituted diphenylcarbazole), Me-4PACz (4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid, and Me-2PACz [2-(3,6-diphenyl-9H-carbazol-9-yl)ethyl]phosphoric acid.

[0042] The material of the perovskite light-absorbing layer in the present invention adopts a material with the ABX 3 structure, where A is a monovalent or divalent cation, including but not limited to Ca 2+ 、Sr 2+ 、formamidine HN=CHNH 3 + (FA), methylamine CH 3 NH 3 + (MA) or a combination thereof; B is a trivalent or tetravalent transition metal cation, including but not limited to Ti 4+ 、Pb 2+ 、Sn 2+ or a combination thereof; X is an anion, including but not limited to O 2- 、Cl-, Br-, I- or a combination thereof.

[0043] The material of the electron transport layer in the present invention is selected from any one or more of PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), BCP (bathocuproine), and C60.

[0044] The material of the metal electrode in the present invention is selected from any one or more of gold, silver, aluminum, and copper.

[0045] The present invention also provides a preparation method of an inverted perovskite solar cell, including preparing an interface modification layer between the perovskite light-absorbing layer and the electron transport layer, and the material of the interface modification layer is guanfacine hydrochloride molecules.

[0046] Preferably, the concentration of the guanfacine hydrochloride molecule is 0.5 - 4 mg / ml. Exemplarily, the concentration of the guanfacine hydrochloride molecule is any one of 0.5 mg / ml, 1 mg / ml, 2 mg / ml, 4 mg / ml or a value between the two. Preferably, the concentration of the guanfacine hydrochloride molecule is 1 - 4 mg / ml. Preferably, the concentration of the guanfacine hydrochloride molecule is 1 - 2 mg / ml.

[0047] The preparation method of the interface modification layer in the present invention is: spin-coating a guanfacine hydrochloride solution on a perovskite light-absorbing layer, and annealing to obtain it.

[0048] The preparation method of the present invention further includes cleaning the conductive glass, preparing a hole transport layer, preparing a perovskite light-absorbing layer, preparing an electron transport layer, and preparing a metal electrode.

[0049] The preparation method of the present invention has the characteristics of simple process and accessible raw materials. By optimizing the preparation process flow, a perovskite solar cell device with excellent optoelectronic properties and stability is successfully prepared. The present invention provides an important theoretical basis and practical guidance for promoting the large-scale development and commercial application of perovskite photovoltaic technology, and lays a solid foundation for further exploring efficient, stable, and low-cost perovskite photovoltaic devices.

[0050] The above is the detailed description of the present invention, and the following are the examples of the present invention.

[0051] Example 1

[0052] This example provides a p-i-n perovskite solar cell, and its structure from bottom to top is in turn: conductive glass (indium tin oxide), hole transport layer (Meo-2PACz), perovskite light-absorbing layer, interface modification layer (guanfacine hydrochloride molecule), electron transport layer (PCBM + BCP), metal electrode (silver).

[0053] This example also provides a preparation method of a p-i-n perovskite solar cell, including the following steps:

[0054] (1) Cleaning the conductive glass: Treating the conductive glass substrate of indium tin oxide (ITO) in an ultraviolet ozone cleaning machine for 15 minutes to wash away the impurities on the substrate surface and improve the wettability;

[0055] (2) Preparing the hole transport layer: Spin-coating 70 ul of a Meo-2PACz solution with a concentration of 0.5 mg / ml (the solvent is absolute ethanol) on the conductive glass, the spin-coating parameters are a rotation speed of 3000 rpm, a spin-coating time of 30 s, and an acceleration of 3000 rpm / s. After spin-coating, anneal at 100 °C for 10 min;

[0056] (3) Preparation of perovskite light-absorbing layer: Weigh 0.0084 g of methylammonium bromide (MABr), 0.0159 g of rubidium iodide (RbI), 0.0195 g of cesium iodide (CsI), 0.0275 g of lead bromide (PbBr), 0.2195 g of formamidinium iodide (FAI), and 0.6569 g of lead iodide (PbI 2 2). Add 1 ml of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (volume ratio 4:1), and place it on a stirrer to stir until completely dissolved to obtain a perovskite precursor solution. Spin-coat 50 μl of the perovskite precursor solution on the hole transport layer in a stepwise spin-coating manner. The spin-coating parameters are a rotation speed of 1000 rpm, a time of 10 s, an acceleration of 1000 rpm / s, a rotation speed of 3000 rpm, a time of 40 s, and an acceleration of 3000 rpm / s. Add 100 μl of anisole as an anti-solvent at the 15th second from the end, and then anneal at 100 °C for 10 min.

[0057] (4) Preparation of interface modification layer: Spin-coat 50 μl of a 0.5 mg / mL guanfacine hydrochloride solution (isopropanol) on the perovskite light-absorbing layer. The spin-coating parameters are a rotation speed of 5000 rpm, a time of 30 s, and an acceleration of 3000 rpm / s. After spin-coating, anneal at 100 °C for 5 min;

[0058] (5) Preparation of electron transport layer: First, spin-coat 50 μl of a PCBM solution with a concentration of 20 mg / ml (solvent is chlorobenzene). The spin-coating parameters are a rotation speed of 1500 rpm, a time of 30 s, and an acceleration of 1500 rpm / s; then spin-coat 50 μl of a BCP solution with a concentration of 0.5 mg / ml (solvent is isopropanol), and the parameters are a rotation speed of 5000 rpm, a time of 30 s, and an acceleration of 2500 rpm / s.

[0059] (6) Preparation of metal electrode: Evaporate a silver metal electrode on the electron transport layer with a thickness of 120 nm.

[0060] Example 2

[0061] Same as Example 1, the only difference is that in the process of preparing the interface modification layer in step (4), the concentration of the guanfacine hydrochloride solution is 1 mg / mL.

[0062] Example 3

[0063] Same as Example 1, the only difference is that in the process of preparing the interface modification layer in step (4), the concentration of the guanfacine hydrochloride solution is 2 mg / mL.

[0064] Example 4

[0065] Same as Example 1, the only difference is that in the process of preparing the interface modification layer in step (4), the concentration of the guanfacine hydrochloride solution is 4 mg / mL.

[0066] Comparative Example 1

[0067] Same as Example 1, except that there is no interfacial modification layer.

[0068] Effect Example 1 Performance Test of Solar Cell Devices

[0069] The perovskite solar cell devices prepared in the examples and comparative examples were subjected to performance tests. The J-V curve diagram is shown in Figure 1 , and the efficiency diagram is shown in Figure 2 , and the performance parameter data are shown in Table 1.

[0070] Table 1

[0071]

[0072]

[0073] It can be seen from Figure 1 to Figure 2 and Table 1 that, compared with Comparative Example 1, after adding guanfacine hydrochloride in the examples of the present invention, V OC 、J SC 、FF, and PCE have all been improved, that is, the performance of the overall device has been improved. Among them, when the concentration of guanfacine hydrochloride in Example 3 is 2 mg / ml, the effect is the best, and the device efficiency reaches 23.01%, which is a very obvious improvement compared with 20.61% of Comparative Example 1. This is because the N-H in the guanidine group of the guanfacine hydrochloride molecule can form hydrogen bonds with I- or Br- on the surface of the perovskite, enhancing the interfacial stability, inhibiting ion migration, reducing charge recombination, and improving the carrier extraction efficiency. In addition, the electron-donating effect of the methoxy group in this molecule may finely tune the surface energy level of the perovskite, improve the energy level matching with the charge transport layer (such as PCBM), and reduce the interfacial barrier to enhance the device performance.

[0074] Figure 3 Figure 37 is the stability test diagram of the perovskite solar cell devices prepared in Example 3 and Comparative Example 1. It can be seen that, compared with the device without the interfacial modification layer in Comparative Example 1, Example 3 of the present invention has good current stability after 500 s of testing, indicating that the stability of the device is better.

[0075] Effect Example 2 Characterization of Film Surface Properties

[0076] The interfacial modification layer prepared in Example 3 and the perovskite light-absorbing layer prepared in Comparative Example 1 were subjected to XRD characterization. The results are shown in Figure 4 . It can be seen that, compared with Comparative Example 1, because the guanfacine hydrochloride molecule was added in Example 3, the characteristic peaks are stronger, indicating that the guanfacine hydrochloride molecule delays the crystallization rate, improves the overall crystallinity of the film, reduces film defects, and improves the device performance.

[0077] The interface modification layer prepared in Example 3 and the perovskite light-absorbing layer prepared in Comparative Example 1 were characterized by SEM, and the results are shown in Figure 5 . Figure 5 It can be seen that at a resolution of 30,000 times of the field emission scanning electron microscope, it can be seen that the addition of guanfacine hydrochloride molecules in Example 3 passivated the defects on the surface of the perovskite, making the grains more uniform. This result is also the same as the XRD test result.

[0078] Test of electron transport efficiency in Effect Example 3

[0079] Figure 6 The cyclic voltammogram (left figure) and electrochemical impedance spectrum (right figure) of the perovskite solar cell devices prepared in Example 3 and Comparative Example 1 are shown. It can be seen that due to the presence of guanfacine hydrochloride molecules in Example 3, the impedance was greatly reduced, the electron transport was optimized, and the electron transport efficiency was improved, indicating that the present invention can improve the energy level matching between the perovskite light-absorbing layer and the charge transport layer and reduce the interfacial barrier.

[0080] The above is only the preferred embodiment of the present invention. It should be noted that the above preferred embodiment should not be regarded as a limitation of the present invention. The protection scope of the present invention should be subject to the scope defined by the claims. For those of ordinary skill in the art, without departing from the spirit and scope of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An inverted perovskite solar cell, characterized in that: An interface modification layer is contained between the perovskite light absorption layer and the electron transport layer of the inverted perovskite solar cell, and the material of the interface modification layer is guanfacine hydrochloride molecules.

2. The inverted perovskite solar cell according to claim 1, characterized in that: The concentration of the guanfacine hydrochloride molecule is 0.5-4 mg / ml.

3. The inverted perovskite solar cell according to claim 1 or 2, characterized in that: The material of the perovskite light absorption layer is a material of ABX3 structure, wherein A is a monovalent or divalent cation, including but not limited to Ca 2+ , Sr 2+ 、Formamidine HN=CHNH3 + (FA), methylamine CH3NH3 + (MA) or a combination thereof; B is a trivalent or tetravalent transition metal cation, including but not limited to Ti 4+ , Pb 2+ Sn 2+ or a combination thereof; X is an anion, including but not limited to O 2- , Cl-, Br-, I- or a combination thereof.

4. The inverted perovskite solar cell according to claim 1 or 2, characterized in that: The material of the electron transport layer is selected from any one or more of PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), BCP (bathocuproine), and C60.

5. The inverted perovskite solar cell according to claim 1 or 2, characterized in that: The inverse perovskite solar cell also includes conductive glass, a hole transport layer and a metal electrode.

6. The inverted perovskite solar cell according to claim 5, characterized in that: The material of the hole transport layer is selected from any one or more of Meo-2PACz, Me-4PACz, and Me-2PACz.

7. A method for preparing an inverse perovskite solar cell, characterized in that: The method comprises preparing an interface modification layer between a perovskite light absorption layer and an electron transport layer, wherein the material of the interface modification layer is guanfacine hydrochloride molecules.

8. The method for preparing an inverse perovskite solar cell according to claim 7, characterized in that: The concentration of the guanfacine hydrochloride molecule is 0.5-4 mg / ml.

9. The method for preparing an inverse perovskite solar cell according to claim 7 or 8, characterized in that: The preparation method of the interface modification layer is as follows: spin coating a guanfacine hydrochloride solution on the perovskite light absorption layer, and annealing to obtain the interface modification layer.

10. The method for preparing an inverse perovskite solar cell according to claim 7 or 8, characterized in that: The preparation method also includes cleaning the conductive glass, preparing a hole transport layer, preparing a perovskite light absorption layer, preparing an electron transport layer, and preparing a metal electrode.

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