An inverse perovskite solar cell utilizing tetrathiofulvalene derivatives to regulate the self-assembled monolayer structure and its fabrication method.

Abstract

This invention discloses an inverse perovskite solar cell and its fabrication method that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer (SAM) assembly structure. The invention uses bis(carbazolium phosphate) SAM-4PABCz as the hole-selective interface layer, employs an ethanol / NMP mixed solvent system, and introduces a tetrathiofulvalene (TTF) derivative as a dopant. By leveraging the steric hindrance effect and non-covalent intermolecular interactions of the TTF derivative, the out-of-plane π-π interactions between bis(carbazolium phosphate) molecules are weakened, inducing the molecules to shift from a high-tilt-angle "standing" stacking of SAM molecules to a low-tilt-angle near-flat arrangement. This regulation strategy effectively suppresses island-like aggregation of SAMs, reduces the interface defect state density, promotes uniform and ordered molecular stacking, and forms a uniform and dense hole-selective contact interface.

Description

Technical Field

[0001] This invention relates to the field of new materials for perovskite solar cells, specifically to an inverted perovskite solar cell with a self-assembled monolayer structure controlled by a tetrathiofulvalene derivative and its preparation method. Background Technology

[0002] Inverted perovskite solar cells have become a core development direction for next-generation photovoltaic technology due to their low-temperature processability, low hysteresis effect, and excellent tandem compatibility. Self-assembled monolayers (SAMs), as the key hole-selective contact layer in inverted devices, directly affect carrier extraction efficiency, interface defect density, and long-term device stability through their molecular assembly structure.

[0003] Currently, bis-carbazole phosphate sintering agents (SAMs) are widely used for interface modification in inverted perovskite solar cells due to their high conjugated rigidity and ordered π-π stacking characteristics, effectively reducing the interfacial work function difference and promoting efficient hole transport. However, the strong intermolecular π-π interactions that drive the formation of ordered π-π stacking of bis-carbazole units can also induce molecular aggregation along the substrate normal, forming island-like domains and pinhole defects, significantly impairing the surface homogeneity and density of the SAM. This aggregation behavior not only increases the interfacial defect state density and exacerbates interfacial nonradiative recombination losses, but also leads to deterioration of carrier transport dynamics, reducing the reproducibility of photoelectric performance in large-area devices and severely limiting the efficiency improvement and industrialization of inverted perovskite solar cells.

[0004] Therefore, developing a simple and efficient molecular strategy to regulate the aggregation behavior of SAM molecules is of significant practical importance for improving the efficiency and stability of perovskite solar cells. While there are reports in the prior art of using sulfur-containing five-membered ring compounds in perovskite solar cells (such as CN119331021A and WO2020011831A1), these compounds are mostly used as host materials for the hole transport layer or electron acceptors, without addressing the gradient regulation of the SAM layer assembly structure. This invention effectively improves the efficiency and stability of perovskite solar cells through gradient substituent design of TTF derivatives and multiple synergistic mechanisms. Summary of the Invention

[0005] To address the aforementioned issues, this study selected tetrathiofulvalene derivatives as candidate materials for regulating the assembly structure of SAMs. Tetrathiofulvalene (TTF) derivatives were introduced as SAM dopants into inverted perovskite solar cells to solve the key problems mentioned above. Tetrathiofulvalene (TTF) derivatives possess controllable intermolecular interactions and steric hindrance effects, allowing for precise control of the stacking patterns and orientation behaviors of adjacent molecules through substituent modification. This provides an ideal molecular regulation platform for resolving the contradiction between "ordered stacking and uniformity" in SAMs.

[0006] Furthermore, the self-assembled monolayer (SAM) doped material has the following structure:

[0007]

[0008] Formula (1) TTF

[0009]

[0010] Equation (2) TET-TTF

[0011]

[0012] Equation (3) TCT-TTF

[0013] Furthermore, the solvent in which the self-assembled monolayer (SAM) doped material is dissolved is N-methylpyrrolidone (NMP);

[0014] Furthermore, the concentration of the self-assembled monolayer (SAM) doped material is 0.5% to 1.5%, preferably 1%;

[0015] Another aspect of the present invention provides an inverted perovskite solar cell, comprising, from bottom to top, a glass substrate, a transparent conductive oxide, a hole transport layer, an organic-inorganic hybrid perovskite active layer, an electron transport layer, a hole blocking layer, and a metal electrode. Simultaneously, the hole transport layer is doped with a tetrathiofulvalene derivative, including TTF, TET-TTF, and TCT-TTF.

[0016] Furthermore, the transparent conductive oxide includes any one of indium tin oxide (ITO) and fluorine-doped indium tin oxide (FTO).

[0017] Furthermore, the hole transport layer is 4PABCz ([4-(9H-9'-phenyl-3,3'-dicarbazo-9-yl)butyl]phosphate), and the solvent used is ethanol (ETOH) with a concentration of 0.2~1 mg / ml, preferably 0.5 mg / ml;

[0018] Furthermore, the organic-inorganic hybrid perovskite active layer precursor solution comprises: Cs0.05FA0.95PbI3, which is a mixture of cesium iodide (CsI), formamidinium hydroiodate (FAI), lead iodide (PbI2), methylammonium chloride (MACl), and lead chloride (PbCl2) in a molar ratio of 0.05:0.95:1.05:0.1:0.03, and the solvent is a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), preferably in a ratio of DMF:DMSO = 4:1.

[0019] Furthermore, a hole blocking layer is provided between the electron transport layer and the electrode layer;

[0020] Furthermore, the electron transport layer is fullerene C60 (C60) with a thickness of 20~30nm, preferably 25nm;

[0021] Furthermore, the hole-blocking layer is 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) with a thickness of 5~10 nm, preferably 7 nm.

[0022] Furthermore, the metal electrode is any one of gold (Au), silver (Ag), and copper (Cu), with a thickness of 80~120nm, preferably 100nm.

[0023] This invention also provides a method for fabricating the applied inverted perovskite solar cell, which includes the following steps:

[0024] (1) Preparation of hole transport layer 4PABCz solution doped with tetrathiofulvalene derivative;

[0025] (2) Perform surface plasma cleaning on the transparent conductive substrate and deposit the hole transport layer prepared in step (1) on its surface;

[0026] (3) Deposit a perovskite layer on the surface of the hole transport layer;

[0027] (4) Deposit an electron transport layer on the perovskite layer;

[0028] (5) Deposit a hole blocking layer on the surface of the electron transport layer;

[0029] (6) Deposit a metal electrode on the surface of the hole blocking layer.

[0030] The specific preparation method of the hole transport layer 4PABCz solution doped with tetrathiofulvalene derivative of the present invention is as follows: dissolve 1 mg of tetrathiofulvalene derivative in 1 ml of NMP, shake and filter thoroughly, and then take 5-15 μL of tetrathiofulvalene derivative solution and dissolve it in 1 ml of 4PABCz solution.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) Gradient precise control of SAM assembly uniformity: The TTF derivative used in this invention relies on the gradual optimization of the substituent structure and its tunable steric hindrance effect and intermolecular non-covalent interaction to achieve stepwise control of the assembly behavior of biscarbazolium phosphate SAM. Compared with the defects of pure SAM in the prior art that is prone to forming out-of-plane one-dimensional π-π stacking and island aggregation, TTF initially intervenes in the aggregation trend. TET-TTF uses the steric hindrance effect of tetraethylthio group to further weaken out-of-plane stacking and reduce local defects. TCT-TTF uses the dipole repulsion and hydrogen bonding brought by cyano group to gradually induce SAM to transform from disordered aggregation to uniform order, so as to achieve uniform and ordered stacking of SAM molecules.

[0033] (2) Reduction of interface defect state density and optimization of carrier transport dynamics: The TTF derivative used in this invention can effectively eliminate interface defects such as pinholes and thickness gradients of SAM by inducing the biscarbazolyl phosphate molecules to change from a "standing" stacking with a high tilt angle to a near-flat arrangement with a low tilt angle. Compared with the problems of high interface defect state density and poor carrier transport caused by SAM aggregation in the prior art, this type of TTF derivative can effectively reduce the interface defect state density, construct a continuous and ordered hole transport channel, and improve carrier extraction and transport dynamics.

[0034] (3) Redox-gated dynamic stability: the first redox potential (TTF / TTF) of TTF, TET-TTF, and TCT-TTF + (·), which can dynamically capture Pb in response to interfacial potential changes induced by ion migration. 2+ with I - Inhibits interface degradation; Second redox potential (TTF) + · / TTF 2+ It is adapted to the strengthening and stabilization requirements under extreme stress. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below:

[0036] Figure 1 This is a schematic diagram of the structure of an inverted perovskite solar cell;

[0037] Figure 2 XRD images of the TCO / SAM / perovskite films in Comparative Example 1, Example 2, Example 5, and Example 8;

[0038] Figure 3 The image shown is the SEM image of Comparative Example 1;

[0039] Figure 4 The SEM image is from Example 2;

[0040] Figure 5 The SEM image is from Example 5;

[0041] Figure 6 The SEM image is from Example 8;

[0042] Figure 7 The small area (0.058 cm²) of Comparative Example 1 and Examples 1-9 of the present invention is shown. 2 Current-voltage (JV) curve of an inverted perovskite solar cell. Detailed Implementation

[0043] The technical solution of the present invention will now be described in complete and detailed manner with reference to specific embodiments. It should be noted that the embodiments described herein are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive step are within the protection scope of the present invention.

[0044] This invention employs a method that utilizes tetrathiofulvalene derivatives to regulate the self-assembled monolayer structure, specifically involving tetrathiofulvalene and its derivatives TTF, TET-TTF, and TCT-TTF. This organic compound not only effectively passivates surface defects in the active layer and improves surface structural stability, but also enhances the hydrophobicity of the thin film surface, ensuring long-term stability during device operation.

[0045] A second aspect of the present invention provides an inverted perovskite solar cell, comprising, from bottom to top, a glass substrate, a transparent conductive oxide, a hole transport layer, an organic-inorganic hybrid perovskite active layer, an electron transport layer, a hole blocking layer, and a metal electrode. The hole transport layer is doped with a tetrathiofulvalene derivative, including TTF, TET-TTF, and TCT-TTF.

[0046] In some specific embodiments of the present invention, the transparent conductive oxide includes any one of indium tin oxide (ITO) and fluorine-doped indium tin oxide (FTO);

[0047] In some specific embodiments of the present invention, the hole transport layer is 4PABCz, and the solvent used is ethanol (ETOH) with a concentration of 0.2~1mg / ml, preferably 0.5mg / ml;

[0048] In some specific embodiments of the present invention, the organic-inorganic hybrid perovskite active layer precursor solution comprises: Cs0.05FA0.95PbI3, which is a mixture of cesium iodide (CsI), formamidinium hydroiodate (FAI), lead iodide (PbI2), methylammonium chloride (MACl), and lead chloride (PbCl2) in a molar ratio of 0.05:0.95:1.05:0.1:0.03, and the solvent is a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), preferably in a ratio of DMF:DMSO=4:1;

[0049] In some specific embodiments of the present invention, a hole blocking layer is provided between the electron transport layer and the electrode layer;

[0050] In some specific embodiments of the present invention, the electron transport layer is fullerene C60 (C60) with a thickness of 20~30nm, preferably 25nm;

[0051] In some specific embodiments of the present invention, the hole blocking layer is 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) with a thickness of 5~10 nm, preferably 7 nm.

[0052] In some specific embodiments of the present invention, the metal electrode is any one of gold (Au), silver (Ag), and copper (Cu), with a thickness of 80~120nm, preferably 100nm.

[0053] This invention also provides a method for fabricating the applied inverted perovskite solar cell, which includes the following steps:

[0054] (1) Preparation of hole transport layer 4PABCz solution doped with tetrathiofulvalene derivative;

[0055] (2) Perform surface plasma cleaning on the transparent conductive substrate and deposit the hole transport layer prepared in step (1) on its surface;

[0056] (3) Deposit a perovskite layer on the surface of the hole transport layer;

[0057] (4) Deposit an electron transport layer on the perovskite layer;

[0058] (5) Deposit a hole blocking layer on the surface of the electron transport layer;

[0059] (6) Deposit a metal electrode on the surface of the hole blocking layer.

[0060] The selection and fabrication processes of the materials for the glass substrate, transparent conductive oxide, hole transport layer, organic-inorganic hybrid perovskite active layer, electron transport layer, hole blocking layer, and metal electrode in the perovskite solar cell are all carried out using conventional techniques in the field. This invention does not impose any special limitations on these aspects, and those skilled in the art can flexibly select and adjust them according to actual application requirements.

[0061] In some specific embodiments of the present invention, the specific preparation method of the hole transport layer 4PABCz solution doped with tetrathiofulvalene derivative is as follows: dissolve 1 mg of tetrathiofulvalene derivative in 1 ml of NMP, shake and filter thoroughly, and then take 5-15 μL of tetrathiofulvalene derivative solution and dissolve it in 1 ml of 4PABCz solution.

[0062] The following describes specific embodiments of this application in detail. It should be noted that all reagents used in the following embodiments are commercially available.

[0063] Comparative Example 1

[0064] This comparative example introduces an inverted perovskite solar cell, as shown in the attached figure. Figure 1 As shown, the battery comprises layers of FTO / SAM / PVK / C60 / BCP / Cu, and its fabrication method includes the following steps:

[0065] (1) Select a fluorine-doped indium tin oxide (FTO) transparent conductive substrate glass with dimensions of 25.2mm×25.2mm×2mm, place it in a plasma cleaning equipment, and perform surface treatment according to the following parameters: moving speed 252mm / s, X-axis coordinate 73.059mm, Y-axis coordinate 180mm, Z-axis coordinate 62mm; after the treatment, transfer the substrate to a nitrogen (N2) glove box, and control the atmosphere conditions of the glove box as follows: temperature ≤20℃, relative humidity (RH) ≤10%.

[0066] (2) Take 100 μL of 0.5 mg / ml [4-(9H-9'-phenyl-3,3'-dicarbazo-9-yl)butyl]phosphoric acid (4PABCz) ethanol solution and add it to the spin-coating substrate. Spin-coat the substrate at a speed of 3000 rpm and an acceleration of 1500 rpm / s for 30 s. Transfer the glass substrate after spin-coating the hole transport layer to a hot stage at 110℃ and anneal for 20 min.

[0067] (3) Dissolve 97.4 mg cesium iodide (CsI), 1225 mg formamidine hydroiodate (FAI), 3631 mg lead iodide (PbI2), 50.65 mg methylammonium chloride (MACl), and 62.57 mg lead chloride (PbCl2) in a mixed organic solvent of 4 ml DMF and 1 ml DMSO, and shake to dissolve for at least 4 hours to obtain a perovskite precursor solution. Take 100 μL of the prepared precursor solution and drop it onto the hole transport layer, and deposit a perovskite film using a spin coating process. The spin coating program is as follows: 1000 rpm rotation speed, 500 rpm acceleration, spin coating for 10 s; 4000 rpm rotation speed, 1000 rpm acceleration, spin coating for 30 s; add 100 μL of anisole as an antisolvent at the 10th second from the end of the program, and then anneal at 120 °C for 15 min on a hot plate.

[0068] (4) Place the glass with the perovskite thin film into the vapor deposition apparatus, start the automatic vacuuming button, and wait until the vacuum reaches 1X10 -4 First, select the C60 evaporation program, set the evaporation temperature to 450℃ and the evaporation rate to 0.2 Å / s, and terminate the process at 25 nm. Then, begin BCP evaporation, setting the evaporation temperature to 200℃ and the evaporation rate to 0.2 Å / s, and terminate the process at 6 nm. Break the vacuum, replace the silver evaporation template, and reactivate the automatic vacuum to 1 x 10⁻⁶. -4 Pa, select Cu evaporation program, set evaporation temperature to 1200℃, evaporation rate to 0.4Å / s, evaporate to 100nm to end the process, break vacuum and collect the wafer.

[0069] Performance testing:

[0070] A circular hole with an area of ​​0.058 cm² is used. 2 Using a 0.1 mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown.

[0071] Example 1

[0072] This embodiment introduces an inverse perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu, and its preparation method is basically the same as that of Comparative Example 1. The difference lies in the doping of tetrathiofulvalene-TTF in the hole transport layer. The specific preparation method of the 4PABCz solution doped with tetrathiofulvalene-TTF is as follows: 1 mg of tetrathiofulvalene-TTF is dissolved in 1 ml of NMP, and after thorough shaking and filtration, 5 μL of the tetrathiofulvalene-TTF solution is taken and dissolved in 1 ml of 4PABCz solution.

[0073] Performance testing:

[0074] A circular hole with an area of ​​0.058 cm² is used. 2 Using a 0.1 mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure. It is evident that compared to the control example, the performance improvement of the embodiment is reflected in the increase in short-circuit current (Jsc): Jsc increases from 24.58 mA / cm². 2 Increased to 25.48 mA / cm 2 This indicates that low-concentration TTF initially intervenes in the out-of-plane stacking of 4PABCz through weak intermolecular π-π competition, reducing pinhole defects and thickness gradients in the SAM layer, resulting in a tighter contact between the perovskite film and the SAM interface, thus significantly improving Jsc. However, unsubstituted TTF lacks orientation, with a small number of molecules dispersed in the SAM layer, resulting in weak modulation of the interface energy level and thus fluctuations in Voc and FF.

[0075] Example 2

[0076] This embodiment introduces an inverted perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu, and its preparation method is basically the same as that in Example 1. The difference lies in the specific preparation method of the 4PABCz solution doped with tetrathiofulvalene-TTF: 1 mg of tetrathiofulvalene-TTF is dissolved in 1 ml of NMP, thoroughly shaken and filtered, and then 10 μL of the tetrathiofulvalene-TTF solution is dissolved in 1 ml of 4PABCz solution.

[0077] Performance testing:

[0078] A circular hole with an area of ​​0.058 cm² is used. 2 Using a 0.1mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure, the performance improvement of the embodiment compared to the control embodiment is reflected in the increase of fill factor (FF) and open-circuit voltage (Voc): FF increases from 84.29% to 85.22%; Voc increases from 1.162V to 1.164V. This indicates that 1% is the optimal doping concentration of TTF, at which point TTF molecules form a moderate non-covalent interaction with 4PABCz, which weakens out-of-plane stacking, reduces local defects, and does not destroy the overall order of the SAM layer, resulting in more uniform precursor spreading and improved film density (see appendix). Figure 4 This improved the crystallization quality of the thin film (see attached image). Figure 2 The low-tilt arrangement of the SAM layers forms a continuous hole transport channel, reducing carrier transport resistance and thus improving FF; the interface defect state density decreases, reducing nonradiative recombination loss and slightly improving Voc.

[0079] Example 3

[0080] This embodiment introduces an inverted perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu, and its preparation method is basically the same as that in Example 1. The difference lies in the specific preparation method of the 4PABCz solution doped with tetrathiofulvalene-TTF: 1 mg of tetrathiofulvalene-TTF is dissolved in 1 ml of NMP, thoroughly shaken and filtered, and then 15 μL of the tetrathiofulvalene-TTF solution is dissolved in 1 ml of 4PABCz solution.

[0081] Performance testing:

[0082] A circular hole with an area of ​​0.058 cm² is used. 2 Using a 0.1 mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure. It can be seen that the results of the embodiment compared with the control embodiment show that the parameters are lower than those of control embodiment 1. This indicates that the excess TTF molecules, due to the lack of directional substituents, are randomly dispersed in the SAM layer, interfering with the anchoring effect of 4PABCz to the substrate, resulting in local disorder in the SAM layer and breakpoints in the carrier transport channels. Therefore, Jsc and FF decrease.

[0083] Example 4

[0084] This embodiment introduces an inverted perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu, and its preparation method is basically the same as that of Comparative Example 1. The difference lies in the doping of the hole transport layer with tetrathiofulvalene derivative-TET-TTF. The specific preparation method of the 4PABCz solution doped with tetrathiofulvalene derivative-TET-TTF is as follows: 1 mg of tetrathiofulvalene derivative-TET-TTF is dissolved in 1 ml of NMP, and after thorough shaking and filtration, 5 μL of the tetrathiofulvalene derivative-TET-TTF solution is taken and dissolved in 1 ml of 4PABCz solution.

[0085] Performance testing:

[0086] A circular hole with an area of ​​0.058 cm² is used. 2Using a 0.1mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure. It is evident that compared to the control example, the performance improvement of the embodiment is reflected in the increase in short-circuit current (Jsc) and fill factor (FF): Jsc increases from 24.58 mA / cm². 2 Increased to 24.93 mA / cm 2 The FF increased from 84.29% to 84.98%. This indicates that the tetraethylthio group of TET-TTF introduces a steric hindrance effect, which more efficiently weakens the out-of-plane π-π stacking of 4PABCz than unsubstituted TTF, further improving the uniformity of the SAM layer and the crystallinity of the perovskite film, thus increasing Jsc. The steric hindrance induces a low tilt angle arrangement of the SAM layer, optimizing carrier transport dynamics and simultaneously increasing FF.

[0087] Example 5

[0088] This embodiment introduces an inverted perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu. Its preparation method is basically the same as that in Example 4, except that the 4PABCz solution doped with tetrathiofulvalene derivative-TET-TTF is specifically prepared by dissolving 1 mg of tetrathiofulvalene derivative-TET-TTF in 1 ml of NMP, shaking and filtering thoroughly, and then dissolving 10 μL of the tetrathiofulvalene derivative-TET-TTF solution in 1 ml of 4PABCz solution.

[0089] Performance testing:

[0090] A circular hole with an area of ​​0.058 cm² is used. 2 Using a 0.1mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure, the performance improvement of the embodiment compared to the control embodiment is reflected in the increase of fill factor (FF) and open-circuit voltage (Voc): FF increases from 84.29% to 86.07%; Voc increases from 1.162V to 1.170V. This indicates that appropriate TET-TTF doping strongly inhibits SAM island aggregation through steric hindrance, further weakens out-of-plane stacking, reduces local defects, and induces the formation of high-crystallinity perovskite films (see attached figure). Figure 2 ) and the growth of large-grain-size perovskite crystals (see appendix) Figure 5 This improves device efficiency.

[0091] Example 6

[0092] This embodiment introduces an inverted perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu, and its preparation method is basically the same as that in Example 4. The difference lies in the specific preparation method of the 4PABCz solution doped with tetrathiofulvalene derivative-TET-TTF. 1 mg of tetrathiofulvalene derivative-TET-TTF is dissolved in 1 ml of NMP, and after thorough shaking and filtration, 15 μL of the tetrathiofulvalene derivative-TET-TTF solution is dissolved in 1 ml of 4PABCz solution.

[0093] Performance testing:

[0094] A circular hole with an area of ​​0.058 cm² is used. 2 Using a 0.1mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure. It is evident that compared to the control example, the performance improvement of the embodiment is reflected in the increase in short-circuit current (Jsc) and fill factor (FF): Jsc increases from 24.58 mA / cm². 2 Increased to 24.70 mA / cm 2 The FF increased from 84.29% to 85.02%, indicating that the excess TET-TTF, with its strong steric hindrance of tetraethyl thio groups, can still suppress the local aggregation of 4PABCz and avoid serious defects in the SAM layer. Therefore, Jsc and FF continued to improve. However, the excess molecules caused local crowding in the SAM layer, which slightly interfered with carrier transport and energy level matching, resulting in a performance improvement of less than 1% doping amount.

[0095] Example 7

[0096] This embodiment introduces an inverted perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu, and its preparation method is basically the same as that of Comparative Example 1. The difference lies in the doping of the hole transport layer with tetrathiofulvalene derivative-TCT-TTF. The specific preparation method of the 4PABCz solution doped with tetrathiofulvalene derivative-TCT-TTF is as follows: 1 mg of tetrathiofulvalene derivative-TCT-TTF is dissolved in 1 ml of NMP, and after thorough shaking and filtration, 5 μL of the tetrathiofulvalene derivative-TCT-TTF solution is taken and dissolved in 1 ml of 4PABCz solution.

[0097] Performance testing:

[0098] A circular hole with an area of ​​0.058 cm² is used. 2Using a 0.1mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure. It is evident that compared to the control example, the performance improvement of the embodiment is reflected in the increase in short-circuit current (Jsc) and fill factor (FF): Jsc increases from 24.58 mA / cm². 2 Increased to 25.40 mA / cm 2 The FF increased from 84.29% to 84.88%, indicating that the cyano group of TCT-TTF introduces dipole repulsion and hydrogen bonding, forming a synergistic effect with steric hindrance—the cyano group forms a weak hydrogen bond with the phosphate group of 4PABCz, inducing the SAM layer to be arranged in a near-planar manner; the improved homogeneity of the SAM layer promotes the crystal growth of perovskite thin films, significantly improving the generation and collection efficiency of photogenerated carriers, and increasing Jsc; the orientation effect of the cyano group allows for efficient control with a small amount of TCT-TTF, passivating interface defects and optimizing energy level matching, resulting in a simultaneous increase in Voc and FF, and a significant increase in PCE due to the doping of tetrathiofulvalene derivatives with orientation effect.

[0099] Example 8

[0100] This embodiment introduces an inverted perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu. Its preparation method is basically the same as that in Example 7, except that the 4PABCz solution doped with tetrathiofulvalene derivative-TCT-TTF is specifically prepared by dissolving 1 mg of tetrathiofulvalene derivative-TCT-TTF in 1 ml of NMP, shaking and filtering thoroughly, and then dissolving 10 μL of the tetrathiofulvalene derivative-TCT-TTF solution in 1 ml of 4PABCz solution.

[0101] Performance testing:

[0102] A circular hole with an area of ​​0.058 cm² is used. 2 Using a 0.1mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure. It is evident that compared to the control example, the performance improvement of the embodiment is reflected in the increase in short-circuit current (Jsc) and open-circuit voltage (Voc): Jsc increases from 24.58 mA / cm². 2 Increased to 25.17 mA / cm 2The Voc increased from 1.162V to 1.173V. This indicates that the synergistic effect of the dipole repulsion of the cyano group and the hydrogen bond improves the wettability of the perovskite precursor solution with appropriate TCT-TTF doping, forming a benign substrate suitable for the spreading and crystallization of the perovskite precursor solution (see appendix). Figure 2 Appendix Figure 6 This reduces carrier surface recombination and grain boundary recombination, achieving optimal efficiency improvement.

[0103] Example 9

[0104] This embodiment introduces an inverted perovskite solar cell that utilizes a tetrathiofulvalene derivative to regulate the self-assembled monolayer structure. The cell comprises layers of FTO / SAM / PVK / C60 / BCP / Cu, and its preparation method is basically the same as that in Example 7. The difference lies in the specific preparation method of the 4PABCz solution doped with tetrathiofulvalene derivative-TCT-TTF. 1 mg of tetrathiofulvalene derivative-TCT-TTF is dissolved in 1 ml of NMP, and after thorough shaking and filtration, 15 μL of the tetrathiofulvalene derivative-TCT-TTF solution is dissolved in 1 ml of 4PABCz solution.

[0105] Performance testing:

[0106] A circular hole with an area of ​​0.058 cm² is used. 2 Using a 0.1mm thick alloy sheet as a light-shielding template, the current-voltage characteristic curves of the inverted perovskite solar cell were tested under AM1.5G illumination. The results are as follows: Figure 7 As shown in the figure. It is evident that compared to the control example, the performance improvement of the embodiment is reflected in the increase in short-circuit current (Jsc) and open-circuit voltage (Voc): Jsc increases from 24.58 mA / cm². 2 Increased to 25.21 mA / cm 2 The Voc increased from 1.162V to 1.170V. This indicates that TCT-TTF, which has a directional effect, can still maintain a certain efficiency improvement under excessive doping due to the synergistic effect of multiple effects such as steric hindrance and hydrogen bonding. Therefore, it is confirmed that the synergistic regulation effect of cyano group and steric hindrance reduces the sensitivity of doped material to concentration, and the performance improvement can still be maintained even with excessive doping, making it more practical.

[0107] The specific parameters of open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF), and power conversion efficiency (PCE) for Comparative Example 1 and Examples 1-9 are shown in Table 1.

[0108] Table 1

[0109] Voc(V) <![CDATA[Jsc(mA / cm 2 )]]> FF(%) PCE (%) Comparative Example 1 Backscan 1.162 24.58 84.29 24.09 Example 1 Backscan 1.141 25.48 83.20 24.20 Example 2 Backscan 1.164 24.56 85.22 24.39 Example 3 Backscan 1.167 24.53 83.99 24.06 Example 4 Backscan 1.158 24.93 84.98 24.54 Example 5 Backscan 1.170 24.58 86.07 24.77 Example 6 Backscan 1.159 24.70 85.02 24.34 Example 7 Backscan 1.167 25.40 84.88 25.16 Example 8 Backscan 1.173 25.17 85.19 25.17 Example 9 Backscan 1.170 25.21 84.35 24.89

[0110] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A trans-perovskite solar cell utilizing a tetrathiofulvalene derivative to regulate the self-assembled monolayer (SAM) assembly structure, characterized in that, It includes a self-assembled monolayer (SAM), wherein the SAM doping material is a tetrathiofulvalene derivative.

2. The inverse perovskite solar cell according to claim 1, which utilizes tetrathiofulvalene derivatives to regulate the self-assembled monolayer (SAM) assembly structure, is characterized in that... The self-assembled monolayer (SAM) doped material has the following structural formula: ； Formula (1) TTF; ； Equation (2) TET-TTF; ； Formula (3) TCT-TTF.

3. The inverse perovskite solar cell according to claim 1, characterized in that, utilizing tetrathiofulvalene derivatives to regulate the self-assembled monolayer (SAM) assembly structure, The self-assembled monolayer (SAM) doped material is first dissolved in N-methylpyrrolidone (NMP) to form a mother liquor, and then mixed with an ethanol solution of 4PABCz, resulting in a final solvent system of ethanol / NMP mixed solvent.

4. The inverse perovskite solar cell according to claim 1, characterized in that, utilizing tetrathiofulvalene derivatives to regulate the self-assembled monolayer (SAM) assembly structure, The doping concentration of the self-assembled monolayer (SAM) doped material is 0.5% to 1.5%, preferably 1%.

5. A reverse perovskite solar cell, employing a pin-type reverse structure, comprising, from bottom to top, a glass substrate, a transparent conductive oxide, a hole transport layer, an organic-inorganic hybrid perovskite active layer, an electron transport layer, a hole blocking layer, and a metal electrode, characterized in that, The hole transport layer is doped with tetrathiofulvalene derivatives, including TTF, TET-TTF, and TCT-TTF.

6. The inverse perovskite solar cell according to claim 5, characterized in that, The tetrathiofulvalene derivative regulates the SAM molecules from a high-tilt-angle upright stacking to a low-tilt-angle near-flat arrangement through steric hindrance and intermolecular non-covalent interactions, and dynamically captures migrating ions through redox properties, thereby reducing the interface defect density.

7. The anti -perovskite solar cell according to claim 5, characterized in that, The transparent conductive oxide includes any one of indium tin oxide (ITO) and fluorine-doped indium tin oxide (FTO); the hole transport layer is [4-(9H-9'-phenyl-3,3'-dicarbazo-9-yl)butyl]phosphate (4PABCz); the organic-inorganic hybrid perovskite active layer composition is: Cs0.05FA0.95PbI3, prepared from a precursor solution including cesium iodide (CsI), formamidine hydroiodate (FAI), lead iodide (PbI2), methylammonium chloride (MACl), and lead chloride (PbCl2); the electron transport layer is a fullerene derivative (C60); the hole blocking layer is copper bath (BCP); and the metal electrode is any one of gold (Au), silver (Ag), and copper (Cu).

8. A reverse perovskite solar cell according to claim 5 or 6, characterized in that, The hole transport layer 4PABCz uses ethanol (ETOH) as the solvent, with a concentration of 0.2~1 mg / ml, preferably 0.5 mg / ml; the organic-inorganic hybrid perovskite active layer precursor solution is a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), preferably in a ratio of DMF:DMSO=4:1; the electron transport layer fullerene C60 (C60) has a thickness of 20~30 nm, preferably 25 nm; the hole blocking layer 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) has a thickness of 5~10 nm, preferably 7 nm; the metal electrode is any one of gold (Au), silver (Ag), and copper (Cu), with a thickness of 80~120 nm, preferably 100 nm.

9. A method for preparing an inverted perovskite solar cell according to any one of claims 5 to 7, characterized in that, Includes the following steps: (1) Preparation of hole transport layer 4PABCz solution doped with tetrathiofulvalene derivative; (2) Perform surface plasma cleaning on the transparent conductive substrate and deposit the hole transport layer prepared in step (1) on its surface; (3) Deposit a perovskite layer on the surface of the hole transport layer; (4) Deposit an electron transport layer on the perovskite layer; (5) Deposit a hole blocking layer on the surface of the electron transport layer; (6) Deposit a metal electrode on the surface of the hole blocking layer.

10. The method of claim 9, wherein the method is characterized by: The specific preparation method of the hole transport layer 4PABCz solution doped with tetrathiofulvalene derivative is as follows: dissolve 1 mg of tetrathiofulvalene derivative in 1 ml of NMP, shake and filter thoroughly, and then take 5-15 μL of tetrathiofulvalene derivative solution and dissolve it in 1 ml of 4PABCz solution.

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