Preparation method of electron transport layer and perovskite solar cell

Abstract

The invention provides an electron transport layer preparation method and a perovskite solar cell. The preparation method comprises the following steps: fully mixing C60 and ethylenediamine salt to obtain a precursor; and placing the precursor in vacuum evaporation equipment for thermal evaporation deposition to form the blended C60 electron transport layer. The perovskite solar cell comprises a transparent conductive layer, a hole transport layer, a perovskite light absorption layer, a C60 electron transport layer, a hole barrier layer and an electrode. According to the method, the problems of energy level mismatch, multiple interface defects, poor contact and serious charge recombination on the perovskite and C60 interface are solved.

Description

Technical Field

[0001] This disclosure relates to the field of solar cell technology, and in particular to a method for preparing an electron transport layer and a perovskite solar cell. Background Technology

[0002] Perovskite solar cells (PSCs) have developed rapidly due to their advantages such as simple fabrication methods, low fabrication costs, and high photoelectric conversion efficiency, with efficiencies exceeding 27%, approaching the level of monocrystalline silicon solar cells.

[0003] Electron transport layers play a crucial role in perovskite solar cells. Fullerenes (C... 60 ) and its derivatives (such as methyl [6,6]-phenyl-C61-butyrate, abbreviated as PCBM) have become one of the most efficient and commonly used electron transport materials due to their high electron affinity, good electron mobility and energy level matching. Although C 60 While the base electron transport layer exhibits excellent performance, the energy level mismatch, ion migration, and non-radiative recombination at its interface with the perovskite directly affect the open-circuit voltage and fill factor, severely restricting the further improvement of perovskite solar cell performance and its commercialization. Summary of the Invention

[0004] In view of this, this disclosure provides an electron transport layer and a method for fabricating perovskite solar cells, which at least partially solves the problem of perovskite and C 60 Problems include energy level mismatch at the interface, numerous interface defects, poor contact, and severe charge recombination.

[0005] This disclosure provides a method for preparing an electron transport layer, comprising: preparing C 60 The precursor is obtained by thoroughly mixing with ethylenediamine salt; the precursor is then placed in a vacuum evaporation deposition apparatus for thermal evaporation deposition to form a blended C. 60 Electron transport layer.

[0006] Another embodiment of this disclosure provides a perovskite solar cell, comprising: a transparent conductive substrate for transporting holes generated within the perovskite solar cell to the outside of the perovskite solar cell; a hole transport layer formed on the transparent conductive substrate for transporting holes to the transparent conductive substrate; a perovskite light-absorbing layer formed on the hole transport layer for absorbing sunlight to generate electron-hole pairs; and an electron transport layer formed on the perovskite light-absorbing layer for transporting electrons generated by the perovskite light-absorbing layer; the electron transport layer is a blend of C prepared by the preparation method of this disclosure. 60Electron transport layer; hole blocking layer, formed on the electron transport layer, used to transport electrons transported by the electron transport layer and block holes generated by the perovskite absorption layer; electrode, formed on the hole blocking layer, used to collect electrons transported by the hole blocking layer and recombine with holes transported by the transparent conductive substrate to form a circuit.

[0007] The electron transport layer fabrication method and perovskite solar cell disclosed herein have at least the following technical advantages:

[0008] Using ethylenediamine salt and C 60 Thoroughly mix and form a blended C layer through thermal evaporation. 60 The electron transport layer eliminates the need for additional passivation processes, thus resolving the issue of perovskite and C. 60 Despite the challenges of energy level mismatch, numerous interface defects, poor contact, and severe charge recombination at the interface, optoelectronic devices based on this electron transport layer can operate effectively under various environmental conditions, thus improving photoelectric conversion efficiency.

[0009] Based on C blend 60 An electron transport layer, adaptable to various bandgap types, can improve the photoelectric conversion efficiency of optoelectronic devices (such as perovskite solar cells). Based on this method, the photoelectric conversion efficiency of perovskite solar cells increased from 23.6% using conventional processes to 26.3%. Specifically, the open-circuit voltage and fill factor improved from ~1.121V and ~82.2% under conventional processes to ~1.176V and ~85.0%, respectively. After 1600 hours of continuous output at maximum power point under one sun, the optimized optoelectronic device retained 95% of its initial efficiency. Attached Figure Description

[0010] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0011] Figure 1 A flowchart illustrating a method for fabricating an electron transport layer according to an embodiment of the present disclosure is shown.

[0012] Figure 2 A schematic diagram of the structure of a perovskite solar cell according to an embodiment of the present disclosure is shown.

[0013] Figure 3 The diagram schematically illustrates the current-voltage characteristic curve of a perovskite solar cell prepared according to Embodiment 1 of this disclosure.

[0014] Figure 4 The schematic illustration shows the operational stability of the perovskite solar cell prepared according to Example 1 of this disclosure.

[0015] Figure 5The transient photocurrent curve of a perovskite solar cell prepared according to Example 1 of this disclosure is illustrated schematically. Detailed Implementation

[0016] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0017] Figure 1 A flowchart illustrating a method for fabricating an electron transport layer according to an embodiment of the present disclosure is shown.

[0018] like Figure 1 As shown, the method for fabricating the electron transport layer may include operations S110 to S120.

[0019] In operation S110, C 60 The precursor is obtained by thoroughly mixing the ethylenediamine salt with the ethylenediamine salt.

[0020] In operation S120, the precursor is placed in a vacuum evaporation equipment for thermal evaporation deposition to form a blended C. 60 Electron transport layer.

[0021] In some embodiments, C 60 The precursor is obtained by thoroughly mixing with ethylenediamine salt, which may include adding 1 mg to 4 mg of ethylenediamine salt to C. 60 The mixture is thoroughly mixed to obtain the precursor.

[0022] Furthermore, the ethylenediamine salt includes at least one of ethylenediamine dihydroiodide and diethylamine tetrafluoroborate.

[0023] In some embodiments, the precursor is placed in the evaporation source of a vacuum evaporation apparatus for thermal evaporation deposition to form a blend of C. 60 The electron transport layer comprises: a blend of C with a thickness of 10 nm to 30 nm deposited in a vacuum evaporation apparatus at a deposition rate of 0.05 Å / s to 2.5 Å / s. 60 Electron transport layer.

[0024] Furthermore, the deposition rate can be 0.1 Å / s to 0.2 Å / s, and the C blend... 60 The thickness of the electron transport layer can be 10 nm to 30 nm.

[0025] In some embodiments, the vacuum degree in the vacuum evaporation equipment is greater than 4 × 10⁻⁶.-4 Pa.

[0026] Figure 2 A cross-sectional view of a perovskite solar cell according to an embodiment of the present disclosure is shown schematically.

[0027] like Figure 2 As shown, the perovskite solar cell includes a transparent conductive substrate 1 and a hole transport layer 2, a perovskite light-absorbing layer 3, an electron transport layer 4, a hole blocking layer 5, and an electrode 6 stacked sequentially on the transparent conductive substrate 1.

[0028] A transparent conductive substrate 1 is used to transport holes generated inside a perovskite solar cell to the outside of the perovskite solar cell.

[0029] Hole transport layer 2 is used to transport holes to the transparent conductive substrate.

[0030] The perovskite light-absorbing layer 3 is used to absorb sunlight to generate electron-hole pairs.

[0031] Electron transport layer 4 is used to transport electrons generated by the perovskite light-absorbing layer. The electron transport layer is a blend of C prepared by the method of this disclosure. 60 Electron transport layer.

[0032] Hole blocking layer 5 is used to transmit electrons transmitted by the electron transport layer and block holes generated by the perovskite absorption layer.

[0033] Electrode 6 is used to collect electrons transported by the hole blocking layer and recombine them with holes transported by the transparent conductive substrate to form a circuit.

[0034] In some embodiments, the hole transport layer material includes nickel oxide or [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid.

[0035] In some embodiments, the hole-blocking layer material includes ALD tin oxide. ALD tin oxide can be a tin oxide thin film prepared based on atomic layer deposition (ALD) technology.

[0036] In some embodiments, the solutes in the perovskite precursor solution used to form the perovskite light-absorbing layer include lead iodide, formamidinium iodide, and methylamine chloride, and the solvents include N,N-dimethylformamide and N-methylpyrrolidone.

[0037] In some embodiments, the solution concentration of the perovskite precursor is 1.5M to 2.0M, and the molar ratio of formamidinium iodide, lead iodide, and methylamine chloride is 1:(1.05 to 1.07):(0.15 to 0.21).

[0038] The embodiments of this disclosure also provide a method for fabricating a perovskite solar cell, comprising: sequentially fabricating a hole transport layer 2, a perovskite light-absorbing layer 3, an electron transport layer 4, a hole blocking layer 5, and an electrode 6 on a transparent conductive substrate 1 to obtain a perovskite solar cell.

[0039] The preparation of the perovskite light-absorbing layer includes: dropping a perovskite precursor solution onto a hole transport layer and spin-coating it. After spin-coating, a vacuum device is used to remove the residual solvent from the film, and then it is transferred to a hot plate for drying and crystallization to obtain the perovskite light-absorbing layer.

[0040] To more clearly illustrate the aforementioned blended electron transport layer and perovskite solar cell, some specific embodiments are provided below.

[0041] Example 1

[0042] The method for preparing the blended electron transport layer in this embodiment may include the following steps.

[0043] Step 1: Add 1 mg of ethylenediamine dihydroiodide to C 60 Mix thoroughly.

[0044] Step 2: Place the mixed precursor in the evaporation source of the vacuum evaporation equipment, ensuring the background vacuum level in the vacuum chamber is better than 4×10⁻⁶. -4 Thermal evaporation deposition was carried out under Pa conditions.

[0045] Step 3: Control the evaporation rate to 0.2 Å / s and the final thickness to 15 nm to obtain the final product.

[0046] Example 2

[0047] The preparation method of this embodiment differs from that of Example 1 in that 1 mg of ethylenediamine dihydroiodide is used instead of 1 mg of diethylamine tetrafluoroborate in step 1. Other implementation details are similar or the same, and will not be repeated here.

[0048] Example 3

[0049] The fabrication of perovskite solar cells in this embodiment may include the following steps.

[0050] Step 1: Clean the conductive substrate 1 with detergent, deionized water, acetone and isopropanol in sequence using ultrasonic cleaning.

[0051] Step 2: After drying the cleaned conductive substrate 1 with a nitrogen gun, carefully treat its surface with ultraviolet-ozone, then spin-coat the hole transport layer solution onto the treated conductive glass, and then perform thermal annealing to form the hole transport layer 2.

[0052] Step 3: The perovskite precursor solution is dropped onto the hole transport layer 2 and spin-coated; after spin-coating, the residual solvent in the film is removed by vacuum device and then transferred to a hot plate for drying and crystallization to obtain the perovskite light-absorbing layer 3.

[0053] Step 4: To C 60 Ethylenediamine salt is added to the mixture and thoroughly mixed; the mixed precursor is then placed in the evaporation source of a vacuum evaporation device for thermal evaporation deposition to form a layer of blended C. 60 Electron transport layer 4.

[0054] Step 5: Via ALD in C 60 A tin oxide layer is formed on electron transport layer 4 as hole blocking layer 5.

[0055] Step 6: Copper (Cu) is deposited on the surface of the hole blocking layer 5 by vacuum evaporation to obtain Cu metal electrode 6, thus achieving a complete inverted perovskite solar cell.

[0056] Comparative Example 1

[0057] The preparation method in Comparative Example 1 is the same as that in Example 3, the only difference being C. 60 The electron transport layer uses only pure C 60 .

[0058] Based on the above embodiments, some experimental data are provided below for illustration.

[0059] Figure 3 The current-voltage characteristic curve of a perovskite solar cell prepared according to Embodiment 1 of this disclosure is schematically shown.

[0060] like Figure 3 As shown, by conducting current density-voltage (JV) tests on the perovskite solar cells prepared in Example 3 and Comparative Example 1, it was found that using a blend of C... 60 The conversion efficiency of the device with the electron transport layer reached 26.26%, while the device prepared in Comparative Example 1 only achieved 23.92%. The open-circuit voltage and fill factor increased from ~1.126V and ~81.95% to ~1.176V and ~84.99%, respectively. This indicates that the efficiency achieved by blending C... 60 The electron transport layer can effectively reduce defects between the perovskite and the electron transport layer, resulting in better energy level matching and enhanced interface carrier extraction, thus enabling perovskite solar cells to have higher photoelectric conversion efficiency.

[0061] Figure 4 The schematic illustration shows the operational stability of a perovskite solar cell prepared according to Embodiment 1 of this disclosure.

[0062] like Figure 4 As shown, using blended C 60The electron transport layer retains 95% of its initial performance after maintaining maximum power output for 1600 hours under standard sunlight, demonstrating high stability.

[0063] Figure 5 The transient photocurrent curve of a perovskite solar cell prepared according to Embodiment 1 of this disclosure is illustrated schematically.

[0064] like Figure 5 As shown, the TPC decay curve of the device reveals that using a blend of C 60 The photocurrent decay lifetime of the electron transport layer decreased from 4.34 μs to 2.94 μs, which means that the charge extraction efficiency has been greatly enhanced, and the charge carriers generated by photoexcitation can be quickly extracted and transported away.

[0065] The above experimental data fully demonstrates the feasibility and advantages of the electron transport layer preparation method and perovskite solar cell provided in this disclosure.

[0066] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A method for fabricating an electron transport layer, characterized in that, include: C 60 The precursor is obtained by thoroughly mixing the ethylenediamine salt with the ethylenediamine salt. The precursor is placed in a vacuum evaporation equipment for thermal evaporation deposition to form a blend of C. 60 Electron transport layer.

2. The preparation method according to claim 1, characterized in that, The C 60 The precursor is obtained by thoroughly mixing with ethylenediamine salt, comprising: Add 1 mg to 4 mg of the ethylenediamine salt to C 60 The mixture is thoroughly mixed to obtain the precursor.

3. The preparation method according to claim 2, characterized in that, The ethylenediamine salt includes at least one of ethylenediamine dihydroiodide and diethylamine tetrafluoroborate.

4. The preparation method according to claim 1, characterized in that, The precursor is placed in a vacuum evaporation equipment for thermal evaporation deposition to form a blended C 60 The electron transport layer includes: In a vacuum evaporation apparatus, blended C with a thickness of 10 nm to 30 nm is deposited at a deposition rate of 0.05 Å / s to 2.5 Å / s. 60 Electron transport layer.

5. The preparation method according to claim 1 or 4, characterized in that, The vacuum degree in the vacuum evaporation equipment is greater than 4 × 10⁻⁴. -4 Pa.

6. A perovskite solar cell, characterized in that, include: A transparent conductive substrate is used to transport holes generated within a perovskite solar cell to the outside of the perovskite solar cell. A hole transport layer is formed on the transparent conductive substrate for transporting holes to the transparent conductive substrate; A perovskite light-absorbing layer, formed on the hole transport layer, is used to absorb sunlight to generate electron-hole pairs; An electron transport layer, formed on the perovskite light-absorbing layer, is used to transport electrons generated by the perovskite light-absorbing layer; the electron transport layer is a blend of C prepared by the preparation method according to any one of claims 1 to 5. 60 Electron transport layer; A hole blocking layer is formed on the electron transport layer to transport electrons transmitted by the electron transport layer and to block holes generated by the perovskite absorption layer. An electrode, formed on the hole-blocking layer, is used to collect electrons transported by the hole-blocking layer and recombine with holes transported by the transparent conductive substrate to form a circuit.

7. The perovskite solar cell according to claim 6, characterized in that, The hole transport layer material includes nickel oxide or [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid.

8. The perovskite solar cell according to claim 6, characterized in that, The hole-blocking layer material includes ALD tin oxide.

9. The perovskite solar cell according to claim 6, characterized in that, The solutes in the perovskite precursor solution used to form the perovskite light-absorbing layer include lead iodide, formamidinium iodide, and methylamine chloride, and the solvents include N,N-dimethylformamide and N-methylpyrrolidone.

10. The perovskite solar cell according to claim 9, characterized in that, The solution concentration of the perovskite precursor is 1.5M~2.0M, and the molar ratio of formamidinium, lead iodide and methylamine chloride is 1:(1.05~1.07):(0.15~0.21).

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