Composite electron transport layer and preparation method and application thereof

Abstract

The invention relates to a composite electron transport layer and a preparation method and application thereof, and the preparation method comprises the following steps: employing an atomic layer deposition method to sequentially deposit a first electron transport layer and a second electron transport layer, and the materials of the first electron transport layer and the second electron transport layer are different; the first electron transport layer and the second electron transport layer each independently include a metal oxide and do not include fullerene. The non-fullerene composite electron transport layer is prepared by adopting the atomic layer deposition method, the cost is low, the stability is high, carrier separation and filling factor improvement are facilitated, the interface stability is also facilitated, and the filling factor and the conversion efficiency of the perovskite cell are further improved. The perovskite battery prepared by the invention is excellent in electrical property and thermal stability.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an electron transport layer, a preparation method and application thereof, and in particular to a composite electron transport layer, a preparation method and application thereof. Background Art

[0002] Although perovskite solar cells have achieved a power conversion efficiency of 26.7%, exceeding many traditional solar technologies, they face difficulties in achieving long-term stability in applications due to their fragile interfaces. Under the combined influence of various environmental factors, such as humidity, oxygen, temperature fluctuations, or light, perovskites are susceptible to degradation, resulting in a decrease in the performance and lifespan of the cells.

[0003] In inverse perovskite solar cells, fullerene and its derivatives are usually used as electron transport layer materials, such as the most common ones are C60, C70, PC61BM, etc. However, this perovskite-electron transport layer interface will form deep well defects, resulting in efficiency loss. The high cost of fullerene and its poor interface bonding and mechanical properties with perovskite have prompted people to look for alternatives. However, potential alternatives, such as metal oxides, are difficult to be compatible with existing processes. The thermal stability of perovskite itself is also a problem that needs to be solved urgently. High temperature annealing is usually used for the best metal oxide treatment. Although sputtering oxides will damage the perovskite surface, directly depositing SnO on the perovskite x The atomic layer will produce chemical reactions and interface barriers, resulting in the power conversion efficiency of the device being lower than normal.

[0004] Therefore, how to prepare an inverted perovskite battery that can effectively reduce the impact of the interface and further improve the thermal stability of the battery has become a problem that needs to be solved urgently. Summary of the Invention

[0005] To address these technical issues, the present invention utilizes atomic layer deposition to produce a non-fullerene composite electron transport layer. This composite electron transport layer's energy level better matches that of the perovskite, facilitating electron extraction and carrier separation, improving the fill factor. It also effectively mitigates interfacial influences, contributing to improved interface stability in perovskite cells, thereby increasing their fill factor and conversion efficiency. The resulting perovskite cell exhibits excellent electrical performance and thermal stability.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a composite electron transport layer, the preparation method comprising the following steps: using atomic layer deposition to sequentially deposit a first electron transport layer and a second electron transport layer to obtain the composite electron transport layer, wherein the first electron transport layer and the second electron transport layer are made of different materials; the first electron transport layer and the second electron transport layer independently include metal oxides and do not include fullerenes.

[0008] The present invention uses atomic layer deposition to produce a non-fullerene composite electron transport layer. The energy level of this composite electron transport layer better matches that of the perovskite, facilitating electron extraction and carrier separation, improving the fill factor, and effectively reducing the effects of the interface, thereby improving the interface stability of the perovskite cell and, consequently, its fill factor and conversion efficiency. The perovskite cell produced by this invention exhibits excellent electrical performance and thermal stability.

[0009] Preferably, the first electron transport layer comprises Al2O3, In2O3, TiO2, SnO x or ZnO, wherein 1≤x≤3, for example, 1, 2 or 3, etc., typical but non-limiting combinations include Al2O3 and In2O3, or TiO2, SnO x and ZnO combination.

[0010] Preferably, the thickness of the first electron transport layer is smaller than the thickness of the second electron transport layer.

[0011] In the present invention, the above-mentioned limitation can quickly extract photogenerated electrons from the perovskite absorption layer and reduce the recombination probability of electrons in the perovskite layer; the second electron transport layer has a large thickness, which can ensure electron transmission while transmitting electrons to the electrode in a more stable manner, avoiding congestion during electron transmission, and allowing electrons to maintain a high migration rate during the entire transmission process, thereby improving the overall performance of the battery.

[0012] Preferably, the thickness of the first electron transport layer is 6 nm-10 nm, for example, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0013] Preferably, the second electron transport layer comprises Al2O3, In2O3, TiO2, SnO x or ZnO, wherein 1≤x≤3, for example, 1, 2 or 3, etc., typical but non-limiting combinations include Al2O3 and In2O3, or TiO2, SnO xPreferably, the thickness of the second electron transport layer is 60 nm to 100 nm, for example, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] Preferably, the chamber vacuum degree of the reaction chamber of the atomic layer deposition method is 10Pa-20Pa, for example, it can be 10Pa, 12Pa, 14Pa, 16Pa, 18Pa or 20Pa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the chamber temperature of the reaction chamber is 80°C-100°C, for example, 80°C, 85°C, 90°C, 95°C or 100°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] Preferably, the deposition method of the first electron transport layer comprises the following steps: (1) using argon as a carrier gas, introducing the raw material of the first electron transport layer into the reaction chamber, and then performing a first purge with argon; (2) introducing the first water vapor, and then performing a second purge with argon; (3) repeating steps (1) and (2) 20 to 50 times in a cycle to obtain the first electron transport layer.

[0017] Specifically, the number of cycle repetitions can be 20 times, 30 times, 40 times or 50 times, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, the raw material of the first electron transport layer includes any one of tetrakis(dimethylamino)tin, tetrakis(dimethylamino)titanium, trimethylaluminum, trimethylindium or diethylzinc, or a combination of at least two thereof.

[0019] Preferably, the introduction time of the raw material of the first electron transport layer is 0.05s-0.2s, for example, 0.05s, 0.08s, 0.1s, 0.15s or 0.2s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the introduction flow rate of the raw material of the first electron transport layer is 80 sccm-120 sccm, for example, it can be 80 sccm, 90 sccm, 100 sccm, 110 sccm or 120 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the first purge time is 8s-12s, for example, 8s, 9s, 10s, 11s or 12s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the flow rate of the first purge is 80 sccm-120 sccm, for example, 80 sccm, 90 sccm, 100 sccm, 110 sccm or 120 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the introduction time of the first water vapor is 0.5s-1s, for example, 0.5s, 0.6s, 0.7s, 0.8s, 0.9s or 1s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the introduction flow rate of the first water vapor is 80 sccm-120 sccm, for example, it can be 80 sccm, 90 sccm, 100 sccm, 110 sccm or 120 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the second purge time is 8s-12s, for example, 8s, 9s, 10s, 11s or 12s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the flow rate of the second purge is 80 sccm-120 sccm, for example, 80 sccm, 90 sccm, 100 sccm, 110 sccm or 120 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the deposition method of the second electron transport layer includes the following steps: (a) using nitrogen as a carrier gas, introducing the raw material of the second electron transport layer into the reaction chamber, and then performing a third purge with nitrogen; (b) after introducing a second water vapor, performing a fourth purge with argon; (c) cyclically repeating steps (a) and (b) 100 to 250 times to obtain the second electron transport layer.

[0028] Specifically, the number of cycle repetitions may be 100 times, 150 times, 200 times, or 250 times, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the raw material of the second electron transport layer includes any one of tetrakis(dimethylamino)tin, tetrakis(dimethylamino)titanium, trimethylaluminum, trimethylindium or diethylzinc, or a combination of at least two thereof.

[0030] Preferably, the introduction time of the raw material of the second electron transport layer is 0.05s-0.2s, for example, 0.05s, 0.08s, 0.1s, 0.15s or 0.2s, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the introduction flow rate of the raw material of the second electron transport layer is 80 sccm-120 sccm, for example, it can be 80 sccm, 90 sccm, 100 sccm, 110 sccm or 120 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the third purge time is 8s-12s, for example, 8s, 9s, 10s, 11s or 12s, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Preferably, the flow rate of the third purge is 80 sccm-120 sccm, for example, 80 sccm, 90 sccm, 100 sccm, 110 sccm or 120 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the introduction time of the second water vapor is 0.5s-1s, for example, it can be 0.5s, 0.6s, 0.7s, 0.8s, 0.9s or 1s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the introduction flow rate of the second water vapor is 80 sccm-120 sccm, for example, it can be 80 sccm, 90 sccm, 100 sccm, 110 sccm or 120 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the fourth purge time is 8s-12s, for example, 8s, 9s, 10s, 11s or 12s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the flow rate of the fourth purge is 80 sccm-120 sccm, for example, 80 sccm, 90 sccm, 100 sccm, 110 sccm or 120 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] In a second aspect, the present invention provides a composite electron transport layer, which is prepared by the preparation method described in the first aspect.

[0039] In a third aspect, the present invention provides a perovskite cell, which includes a substrate, a conductive anode, a hole transport layer, a perovskite light absorption layer, a passivation layer, the composite electron transport layer described in the second aspect, and a conductive cathode.

[0040] The inverse perovskite battery prepared by the present invention can effectively reduce the influence of the interface and further improve the power conversion efficiency of the battery.

[0041] Preferably, the material of the substrate includes any one of glass, silicon wafer, PET or PI, or a combination of at least two of them. Typical but non-limiting combinations include a combination of glass and silicon wafer, or a combination of silicon wafer, PET and PI.

[0042] Preferably, the material of the conductive anode includes any one of ITO, FTO or Ag nanowires, or a combination of at least two of them. Typical but non-limiting combinations include a combination of ITO and FTO, or a combination of ITO, FTO and Ag nanowires.

[0043] Preferably, the material of the hole transport layer includes NiO x , Cu2O, P3HT, PTAA or Spiro-OMeTAD, or a combination of at least two thereof, wherein 1≤x≤3, for example, 1, 2 or 3, etc., a typical but non-limiting combination includes NiO x and Cu2O, or a combination of P3HT, PTAA, and Spiro-OMeTAD.

[0044] Preferably, the material of the perovskite light-absorbing layer includes ABX3 type perovskite, wherein A is any one of cesium ion, rubidium ion, methylamine or formamidinium group, or a combination of at least two, typical but non-limiting combinations include a combination of cesium ion and rubidium ion, or a combination of rubidium ion, methylamine and formamidinium group, B is lead ion and / or tin ion, X is any one of bromide ion, iodide ion or chloride ion, or a combination of at least two, typical but non-limiting combinations include a combination of bromide ion and iodide ion, or a combination of bromide ion, iodide ion and chloride ion.

[0045] Preferably, the material of the passivation layer includes any one of butylammonium bromide, hexylammonium bromide or phenylethylamine iodide, or a combination of at least two of them. Typical but non-limiting combinations include a combination of butylammonium bromide and hexylammonium bromide, or a combination of butylammonium bromide, hexylammonium bromide and phenylethylamine iodide.

[0046] Preferably, the material of the conductive cathode includes any one of Au electrode, Ag electrode, Cu electrode, Pt electrode or C electrode, or a combination of at least two of them. Typical but non-limiting combinations include a combination of Au electrode and Ag electrode, or a combination of Cu electrode, Pt electrode and C electrode.

[0047] Compared with the prior art, the present invention has at least the following beneficial effects:

[0048] (1) The present invention adopts the atomic layer deposition method to prepare a non-fullerene composite electron transport layer. The energy level of the composite electron transport layer is more matched with the perovskite, which is conducive to the extraction of electrons and separation of carriers, thereby improving the fill factor.

[0049] (2) The present invention can effectively reduce the influence of the interface through the composite electron transport layer, which is beneficial to improving the interface stability of the perovskite battery and further improving its fill factor and conversion efficiency.

[0050] (3) The use of a composite electron transport layer instead of fullerene greatly improves the stability of the battery while reducing costs, which is beneficial to improving the bonding between interfaces and reducing the potential barrier between perovskite and the electron transport layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the structure of the perovskite solar cell prepared according to Example 1 of the present invention;

[0052] Figure 2 1 is a stability test curve of the perovskite solar cell prepared in Example 1 of the present invention and Comparative Example 1;

[0053] Among them, 1 is the substrate, 2 is the conductive anode, 3 is the hole transport layer, 4 is the perovskite light absorption layer, 5 is the passivation layer, 6 is the composite electron transport layer, and 7 is the conductive cathode. DETAILED DESCRIPTION

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0055] Example 1

[0056] This embodiment provides a method for preparing a composite electron transport layer, the preparation method comprising the following steps:

[0057] (I) In a reaction chamber at a vacuum degree of 13 Pa and a temperature of 90° C., tetrakis(dimethylamino)tin was introduced into the reaction chamber using argon as a carrier gas for an introduction time of 0.1 s at a flow rate of 100 sccm. A first purge was performed using argon for a purge time of 10 s at a flow rate of 100 sccm.

[0058] (II) After the first water vapor is introduced again, the introduction time is 0.6 s and the introduction flow rate is 100 sccm, and a second purge is performed with argon gas, the purge time is 10 s and the purge flow rate is 100 sccm;

[0059] (III) Repeating steps (I) and (II) 35 times to obtain a SnO2 first electron transport layer with a thickness of 8 nm;

[0060] (IV) In a reaction chamber having a vacuum degree of 13 Pa and a temperature of 90° C., titanium tetrachloride was introduced into the reaction chamber using nitrogen as a carrier gas for an introduction time of 0.1 s at an introduction flow rate of 80 sccm, and a third purge was performed with nitrogen for an introduction time of 8 s at a purge flow rate of 100 sccm;

[0061] (V) introducing a second water vapor stream for 0.5 s at a flow rate of 100 sccm, and performing a fourth purge with nitrogen for 8 s at a flow rate of 100 sccm;

[0062] (VI) Repeat steps (IV) and (V) 200 times to obtain a TiO2 second electron transport layer with a thickness of 80 nm.

[0063] Figure 1 1 is a schematic structural diagram of the perovskite solar cell prepared in accordance with Example 1 of the present invention. As can be seen from the figure, the perovskite solar cell prepared in accordance with Example 1 of the present invention has a trans structure, including a substrate 1, a conductive anode 2, a hole transport layer 3, a perovskite light absorbing layer 4, a passivation layer 5, the composite electron transport layer 6 as described above, and a conductive cathode 7 stacked in sequence; wherein the substrate 1 is glass, the conductive anode 2 is ITO (indium tin oxide), the hole transport layer 3 is a nickel oxide layer, and the perovskite light absorbing layer 4 is Cs 0.05 MA 0.05 FA 0.9 Pb(I 0.95 Br 0.05 layer, the passivation layer 5 is a butylammonium bromide layer, and the conductive cathode 7 is a Cu layer.

[0064] Example 2

[0065] This embodiment provides a method for preparing a composite electron transport layer, the preparation method comprising the following steps:

[0066] (I) In a reaction chamber at a vacuum degree of 10 Pa and a temperature of 100° C., trimethylindium was introduced into the reaction chamber using argon as a carrier gas for 0.05 s at a flow rate of 120 sccm, and a first purge was performed with argon for 8 s at a flow rate of 120 sccm;

[0067] (II) After the first water vapor is introduced again, the introduction time is 0.5 s and the introduction flow rate is 120 sccm, and a second purge is performed with argon gas, the purge time is 8 s and the purge flow rate is 120 sccm;

[0068] (III) Repeating steps (I) and (II) 30 times to obtain a 6 nm thick In2O3 first electron transport layer;

[0069] (IV) In a reaction chamber having a vacuum degree of 10 Pa and a temperature of 100° C., diethylzinc was introduced into the reaction chamber using nitrogen as a carrier gas for 0.05 s at a flow rate of 120 sccm, and a third purge was performed using nitrogen for 8 s at a flow rate of 120 sccm;

[0070] (V) introducing a second water vapor for 0.5 s at a flow rate of 80 sccm, and performing a fourth purge with nitrogen for 8 s at a flow rate of 120 sccm;

[0071] (VI) Repeat steps (IV) and (V) 180 times to obtain a ZnO second electron transport layer with a thickness of 60 nm.

[0072] Example 3

[0073] This embodiment provides a method for preparing a composite electron transport layer, the preparation method comprising the following steps:

[0074] (I) In a reaction chamber having a vacuum degree of 20 Pa and a temperature of 80° C., titanium tetrachloride was introduced into the reaction chamber using argon as a carrier gas for an introduction time of 0.2 s and an introduction flow rate of 80 sccm. A first purge was performed using argon for a purge time of 12 s and a purge flow rate of 80 sccm.

[0075] (II) After the first water vapor is introduced again, the introduction time is 1 s and the introduction flow rate is 80 sccm, and a second purge is performed with argon gas, the purge time is 12 s and the purge flow rate is 80 sccm;

[0076] (III) Repeating steps (I) and (II) 40 times to obtain a TiO2 first electron transport layer with a thickness of 10 nm;

[0077] (IV) In a reaction chamber having a vacuum degree of 20 Pa and a temperature of 80° C., trimethylaluminum was introduced into the reaction chamber using nitrogen as a carrier gas for 0.2 s at a flow rate of 80 sccm. A third purge was performed using nitrogen for 12 s at a flow rate of 80 sccm.

[0078] (V) introducing a second water vapor for 1 second at a flow rate of 80 sccm, and performing a fourth purge with nitrogen for 12 seconds at a flow rate of 80 sccm;

[0079] (VI) Repeat steps (IV) and (V) 220 times to obtain an Al2O3 second electron transport layer with a thickness of 100 nm.

[0080] Example 4

[0081] The only difference between this embodiment and embodiment 1 is that, except for cyclically repeating steps (I) and (II) 70 times to obtain a SnO2 electron transport layer with a thickness of 16 nm, the rest is the same as embodiment 1.

[0082] Example 5

[0083] The only difference between this embodiment and embodiment 1 is that, except for cyclically repeating steps (I) and (II) 10 times to obtain a SnO2 electron transport layer with a thickness of 2 nm, the rest is the same as embodiment 1.

[0084] Example 6

[0085] The only difference between this embodiment and embodiment 1 is that, except for cyclically repeating steps (IV) and (V) 50 times to obtain a TiO2 electron transport layer with a thickness of 20 nm, the rest is the same as embodiment 1.

[0086] Example 7

[0087] The only difference between this embodiment and embodiment 1 is that, except for cyclically repeating steps (IV) and (V) 300 times to obtain a TiO2 electron transport layer with a thickness of 120 nm, the rest is the same as embodiment 1.

[0088] Example 8

[0089] The only difference between this embodiment and embodiment 1 is that, except that the introduction time of tetrakis(dimethylamino)tin in step (I) is 0.01 s, the rest are the same as those in embodiment 1.

[0090] Example 9

[0091] The only difference between this embodiment and embodiment 1 is that, except that the introduction time of tetrakis(dimethylamino)tin in step (I) is 0.25 s, the rest are the same as those in embodiment 1.

[0092] Example 10

[0093] The only difference between this embodiment and embodiment 1 is that, except for the introduction time of titanium tetrachloride in step (IV) being 0.01 s, the rest is the same as embodiment 1.

[0094] Example 11

[0095] The only difference between this embodiment and embodiment 1 is that, except for the introduction time of titanium tetrachloride in step (IV) being 0.25 s, the rest are the same as those in embodiment 1.

[0096] Comparative Example 1

[0097] The only difference between this comparative example and Example 1 is that, except that steps (IV) to (VI) are not performed and only a SnO2 electron transport layer is obtained, the rest are the same as Example 1.

[0098] Figure 2 This is the stability test curve of the perovskite solar cell prepared corresponding to Example 1 of the present invention and Comparative Example 1. It can be seen from the figure that the T80 life of Comparative Example 1 is only 200 hours, while the T80 life of Example 1 can reach 1200 hours, indicating that the stability of the perovskite battery is greatly improved after the composite electron transport layer is adopted.

[0099] Comparative Example 2

[0100] The only difference between this comparative example and Example 1 is that, except that steps (I) to (III) are not performed and only a TiO2 electron transport layer is obtained, the rest are the same as Example 1.

[0101] Comparative Example 3

[0102] This comparative example provides a method for preparing an electron transport layer, which comprises the following steps:

[0103] (I) In a reaction chamber with a vacuum degree of 13 Pa and a temperature of 90°C, C 60 Introduce into the reaction chamber with an introduction time of 0.1s and an introduction flow rate of 100sccm, and perform a first purge with argon with a purge time of 10s and a purge flow rate of 100sccm;

[0104] (II) After the first water vapor is introduced again, the introduction time is 0.6 s and the introduction flow rate is 100 sccm, and a second purge is performed with argon gas, the purge time is 10 s and the purge flow rate is 100 sccm;

[0105] (III) Repeat steps (I) and (II) 200 times to obtain a C 60 Electron transport layer.

[0106] Test Method

[0107] The composite electron transport layers prepared in Examples 1 to 11 and Comparative Examples 1 to 3 were assembled as follows: Figure 1 The perovskite cell shown in the figure, the preparation method of the test perovskite cell includes the following steps:

[0108] ① ITO glass substrate was prepared by laser scribing P1;

[0109] ② Use deionized water to scrub the ITO conductive substrate, and then ultrasonicate with deionized water, acetone, and isopropyl alcohol for 30 minutes each;

[0110] ③ Depositing a hole transport layer on the cleaned substrate, where nickel oxide is used;

[0111] ④ In a nitrogen glove box, CsI, FAI, MAI, PbI2, and PbBr2 were weighed according to the molar ratio to obtain the component Cs 0.05 MA 0.05 FA 0.9 Pb(I 0.95 Br 0.05 ) perovskite and dissolved it in a DMF:DMSO = 4:1 solvent with a precursor concentration of 1.0 mol / L. A perovskite film with a thickness of 450 nm was prepared using a slot-slit coating method.

[0112] ⑤ Dissolve butylammonium bromide in isopropanol to prepare a butylammonium bromide passivation agent with a concentration of 1 mg / mL, apply a passivation layer using a slit coating, and then anneal at 100°C for 5 minutes to obtain a butylammonium bromide passivation layer;

[0113] ⑥ A composite electron transport layer was prepared according to the methods of Examples 1 to 11 and Comparative Examples 1 to 3;

[0114] ⑦ Use laser scribing to form a second etching groove P2 that penetrates the hole transport layer, perovskite light absorption layer, composite electron transport layer, passivation layer and hole blocking layer;

[0115] ⑧ Use thermal evaporation to deposit a 150nm thick Cu layer as the cathode electrode.

[0116] ⑨ Laser scribing is performed again to form a third etching groove P3 that penetrates the cathode electrode layer to obtain a sub-cell, and all the sub-cells are connected in series to obtain the perovskite solar module.

[0117] The perovskite cells corresponding to Examples 1 to 11 and Comparative Examples 1 to 3 were tested for short-circuit current (Isc), open-circuit voltage (Voc), fill factor (FF), conversion efficiency (Eff), aperture area, and stability, and the test results are recorded in Table 1.

[0118] Table 1

[0119]

[0120]

[0121] The test results show that:

[0122] (1) As can be seen from Examples 1 to 11 and Comparative Examples 1 to 3, the present invention employs atomic layer deposition to prepare a non-fullerene composite electron transport layer. The energy level of the composite electron transport layer is more closely matched to that of the perovskite, facilitating electron extraction and carrier separation, thereby increasing current density. It can also effectively reduce the effects of the interface, thereby improving the interface stability of the perovskite cell and thereby increasing its fill factor and conversion efficiency. The perovskite cell prepared by the present invention exhibits excellent electrical performance and thermal stability.

[0123] (2) It can be seen from Examples 1 and 4 to 7 that the present invention further regulates the thickness of the SnO2 first electron transport layer and the TiO2 second electron transport layer, thereby obtaining a corresponding perovskite battery with a high filling factor and photoelectric conversion efficiency, and further improves the stability of the perovskite battery.

[0124] (3) It can be seen from Examples 1 and 8 to 11 that, by further regulating the introduction time of the two electron transport layers, the corresponding perovskite battery obtained has a high fill factor and photoelectric conversion efficiency, and the stability of the perovskite battery is further improved.

[0125] In summary, the present invention utilizes atomic layer deposition to prepare a non-fullerene composite electron transport layer. This composite electron transport layer's energy level better matches that of the perovskite, facilitating electron extraction and carrier separation, increasing current density. It also effectively mitigates interfacial influences, improving the interfacial stability of the perovskite cell and, consequently, its fill factor and conversion efficiency. The perovskite cell prepared by the present invention exhibits excellent electrical performance and thermal stability.

[0126] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a composite electron transport layer, characterized in that: The preparation method comprises the following steps: Depositing a first electron transport layer and a second electron transport layer in sequence by atomic layer deposition to obtain the composite electron transport layer; The first electron transport layer and the second electron transport layer are made of different materials; The first electron transport layer and the second electron transport layer each independently include a metal oxide and do not include fullerene.

2. The preparation method according to claim 1, characterized in that The first electron transport layer includes Al2O3, In2O3, TiO2, SnO x or any one or a combination of at least two of ZnO, wherein 1≤x≤3; Preferably, the thickness of the first electron transport layer is less than the thickness of the second electron transport layer; Preferably, the thickness of the first electron transport layer is 6 nm to 10 nm; Preferably, the second electron transport layer comprises Al2O3, In2O3, TiO2, SnO x or any one or a combination of at least two of ZnO, wherein 1≤x≤3; Preferably, the second electron transport layer has a thickness of 60 nm to 100 nm.

3. The preparation method according to claim 1 or 2, characterized in that The vacuum degree of the reaction chamber of the atomic layer deposition method is 10Pa-20Pa; Preferably, the chamber temperature of the reaction chamber is 80°C-100°C.

4. The preparation method according to any one of claims 1 to 3, characterized in that The deposition method of the first electron transport layer comprises the following steps: (1) Using argon as a carrier gas, the raw materials of the first electron transport layer are introduced into the reaction chamber, and then the first purge is performed with argon; (2) After the first water vapor is introduced again, a second purge is performed with argon gas; (3) Repeat steps (1) and (2) 20 to 50 times to obtain the first electron transport layer.

5. The preparation method according to claim 4, characterized in that The introduction time of the raw materials of the first electron transport layer is 0.05s-0.2s; Preferably, the introduction flow rate of the raw material of the first electron transport layer is 80 sccm-120 sccm; Preferably, the first purge time is 8s-12s; Preferably, the flow rate of the first purge is 80 sccm-120 sccm; Preferably, the introduction time of the first water vapor is 0.5s-1s; Preferably, the introduction flow rate of the first water vapor is 80 sccm-120 sccm; Preferably, the second purge time is 8s-12s; Preferably, the flow rate of the second purge is 80 sccm-120 sccm.

6. The preparation method according to any one of claims 1 to 5, characterized in that The deposition method of the second electron transport layer comprises the following steps: (a) using nitrogen as a carrier gas, introducing the raw materials of the second electron transport layer into the reaction chamber, and then performing a third purge with nitrogen; (b) after introducing the second water vapor, performing a fourth purge with nitrogen; (c) cyclically repeating step (a) and step (b) 100 to 250 times to obtain the second electron transport layer.

7. The preparation method according to claim 6, characterized in that The introduction time of the raw materials of the second electron transport layer is 0.05s-0.2s; Preferably, the introduction flow rate of the raw material of the second electron transport layer is 80 sccm-120 sccm; Preferably, the third purge time is 8s-12s; Preferably, the flow rate of the third purge is 80 sccm-120 sccm; Preferably, the introduction time of the second water vapor is 0.5s-1s; Preferably, the introduction flow rate of the second water vapor is 80 sccm-120 sccm; Preferably, the fourth purge time is 8s-12s; Preferably, the flow rate of the fourth purge is 80 sccm-120 sccm.

8. A composite electron transport layer, characterized in that The composite electron transport layer is prepared by the preparation method according to any one of claims 1 to 7.

9. A perovskite battery, characterized in that: The perovskite cell comprises a substrate, a conductive anode, a hole transport layer, a perovskite light absorption layer, a passivation layer, the composite electron transport layer according to claim 8 and a conductive cathode.

10. The perovskite cell according to claim 9, characterized in that The material of the substrate includes any one of glass, silicon wafer, PET or PI or a combination of at least two; Preferably, the material of the conductive anode includes any one of ITO, FTO or Ag nanowires or a combination of at least two thereof; Preferably, the material of the hole transport layer includes NiO x , any one of Cu2O, P3HT, PTAA or Spiro-OMeTAD or a combination of at least two thereof, wherein 1≤x≤3; Preferably, the material of the perovskite light-absorbing layer includes ABX3-type perovskite, wherein A is any one of cesium ion, rubidium ion, methylamine group or formamidinium group or a combination of at least two thereof, B is lead ion and / or tin ion, and X is any one of bromide ion, iodide ion or chloride ion or a combination of at least two thereof; Preferably, the material of the passivation layer includes any one of butylammonium bromide, hexylammonium bromide or phenylethylamine iodide, or a combination of at least two thereof; Preferably, the material of the conductive cathode includes any one of Au electrode, Ag electrode, Cu electrode, Pt electrode or C electrode, or a combination of at least two of them.

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