Nitrogen-doped nickel oxide, preparation method thereof and perovskite solar cell

Abstract

The invention discloses nitrogen-doped nickel oxide, a preparation method thereof and a perovskite solar cell. The method comprises the following steps: placing a nickel oxide material in a heat treatment furnace; ammonia gas is introduced into the heat treatment furnace, and the atmosphere in the heat treatment furnace is kept stable; and heating the heat treatment furnace to 150-450 DEG C, and preserving heat for 5-10 hours to obtain the nitrogen-doped nickel oxide. The valence band energy level of the nitrogen-doped nickel oxide is close to the valence band energy level of the transparent conductive oxide layer and the perovskite light absorption layer, efficient transmission of holes from the perovskite light absorption layer to the nitrogen-doped nickel oxide is facilitated, and energy loss is reduced; the conduction band (CB) of the nitrogen-doped nickel oxide is well matched with the conduction band energy level of the perovskite, so that the backflow of electrons to the nickel oxide layer is inhibited, and the recombination loss is reduced. The nitrogen-doped nickel oxide has better conductivity, and when the nitrogen-doped nickel oxide is applied to a hole transport layer of a perovskite solar cell, the perovskite solar cell has better photoelectric conversion performance and stability.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to nitrogen-doped nickel oxide and a preparation method thereof, and a perovskite solar cell. Background Art

[0002] With the development of the global economy and the growth of population, the pollution problem caused by fossil energy is becoming increasingly serious, and people are beginning to explore alternatives to traditional energy. Solar energy is the most abundant and easily accessible renewable energy on the earth. Solar cells are semiconductor devices that directly use solar energy to generate electricity through the photoelectric conversion effect. However, the low energy conversion efficiency and high cost of solar cells have become two major problems restricting their development. Nickel oxide (NiO x ) is an important inorganic hole transport material and plays a key role in perovskite solar cells. However, pure nickel oxide has poor conductivity, which leads to severe charge recombination at the device interface, thus reducing the hole extraction efficiency. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention provides a nitrogen-doped nickel oxide, a preparation method thereof, and a perovskite solar cell.

[0005] In a first aspect, the present invention provides a method for preparing nitrogen-doped nickel oxide, comprising the following steps:

[0006] (1) placing the nickel oxide material in a heat treatment furnace;

[0007] (2) introducing ammonia into the heat treatment furnace to maintain a stable atmosphere in the heat treatment furnace;

[0008] (3) The heat treatment furnace is heated to 150-450° C. and then kept at this temperature for 5-10 hours to obtain nitrogen-doped nickel oxide.

[0009] Furthermore, the nickel oxide material doping includes one of nickel oxide film and nano nickel oxide particles.

[0010] Furthermore, the nickel oxide material is doped with one or both of Mg and Zn.

[0011] Furthermore, the pressure in the heat treatment furnace is 1.01-1.2 atm.

[0012] Furthermore, the pressure in the heat treatment furnace is 1.05-1.1 atm.

[0013] In a second aspect, the present invention provides nitrogen-doped nickel oxide prepared by the preparation method provided in the first aspect.

[0014] Furthermore, the nitrogen doping amount in the nitrogen-doped nickel oxide is 1 to 15 at %.

[0015] In a third aspect, the present invention proposes a perovskite solar cell, comprising a transparent conductive oxide layer, a hole transport layer, a perovskite light absorbing layer, an electron transport layer, and a back electrode stacked in sequence, wherein the hole transport layer is nitrogen-doped nickel oxide prepared by the preparation method proposed in the first aspect or the nitrogen-doped nickel oxide proposed in the second aspect.

[0016] Furthermore, the thickness of the hole transport layer is 20-80 nm.

[0017] Furthermore, nitrogen element is uniformly doped in the hole transport layer.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] The valence band of the nitrogen-doped nickel oxide of the present invention is close to the valence band energy level of the transparent conductive oxide layer and the perovskite light absorbing layer, which is conducive to the efficient transmission of holes from the perovskite light absorbing layer to the nitrogen-doped nickel oxide and reduces energy loss; the conduction band (CB) of the nitrogen-doped nickel oxide is well matched with the conduction band energy level of the perovskite, which inhibits the backflow of electrons to the nickel oxide layer and reduces the recombination loss.

[0020] The nitrogen-doped nickel oxide of the present invention has better electrical conductivity, and is applied to the hole transport layer of a perovskite solar cell, so that the perovskite solar cell has better photoelectric conversion performance and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0022] Figure 1 The present invention is a flow chart of the preparation method of nitrogen-doped nickel oxide. DETAILED DESCRIPTION

[0023] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0024] The nitrogen-doped nickel oxide and its preparation method and the perovskite solar cell of the present invention are described below in conjunction with the accompanying drawings.

[0025] Preparation method of nitrogen-doped nickel oxide, such as Figure 1 Said, comprising the following steps:

[0026] (1) placing the nickel oxide material in a heat treatment furnace;

[0027] (2) introducing ammonia into the heat treatment furnace to maintain a stable atmosphere in the heat treatment furnace;

[0028] (3) The heat treatment furnace is heated to 150-450° C. and then kept at this temperature for 5-10 hours to obtain nitrogen-doped nickel oxide.

[0029] In some embodiments, the nickel oxide material doping includes one of a nickel oxide film and nano nickel oxide particles.

[0030] In some embodiments, the nickel oxide material is further doped with elements such as Mg and Zn.

[0031] In some embodiments, the pressure in the heat treatment furnace is 1.01-1.2 atm.

[0032] In some embodiments, the pressure in the heat treatment furnace is 1.05-1.1 atm.

[0033] It is understandable that in step (2), ammonia gas may be introduced into the heat treatment furnace with or without circulation, and the ammonia gas introduced only needs to be able to maintain a stable atmosphere in the furnace.

[0034] In some embodiments, the nitrogen doping amount in the nitrogen-doped nickel oxide is 1 to 15 at %.

[0035] When the nickel oxide layer is used as a hole transport layer of a perovskite solar cell, the thickness thereof is 20 to 80 nm, which is relatively small. After nitrogen doping, the nitrogen element can be uniformly doped.

[0036] Perovskite solar cells include a transparent conductive oxide layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, and a back electrode stacked in sequence, wherein the hole transport layer material is nitrogen-doped nickel oxide, the thickness of the hole transport layer is 20 to 80 nm, and the nitrogen element is uniformly doped in the hole transport layer.

[0037] The valence band energy level of nitrogen-doped nickel oxide is close to that of the transparent conductive oxide layer and the perovskite light-absorbing layer, which is conducive to the efficient transmission of holes from the perovskite light-absorbing layer to the nitrogen-doped nickel oxide and reduces energy loss; the conduction band (CB) of nitrogen-doped nickel oxide matches well with the conduction band energy level of perovskite, which inhibits the backflow of electrons to the nickel oxide layer and reduces the recombination loss.

[0038] The nitrogen-doped nickel oxide of the present invention has better electrical conductivity, and is applied to the hole transport layer of a perovskite solar cell, so that the perovskite solar cell has better photoelectric conversion performance and stability.

[0039] The present invention is described below in conjunction with specific examples. The test materials and reagents used in the following examples, unless otherwise specified, can be obtained from commercial sources. If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0040] Example 1

[0041] (1) 3*3cm 2 The ITO substrate was cleaned, a 10 g / ml nano nickel oxide aqueous solution was prepared, ultrasonic dispersion was performed for 10 min, and a NiO film was scraped on the surface of the ITO substrate by a scraping method (scraping speed 5 mm / s); and dried on a hot stage at 100° C. for 10 min to obtain an undoped nickel oxide charge transport layer with a thickness of 40 nm.

[0042] (2) The undoped nickel oxide charge transport layer is placed in a heat treatment furnace, ammonia gas is introduced into the heat treatment furnace, and the pressure is maintained at 1.05 atm to keep the atmosphere in the furnace stable. The heat treatment furnace is heated to 350°C and kept warm for 5 hours to obtain a nitrogen-doped nickel oxide hole transport layer. The sample is taken out after cooling.

[0043] (3) Prepare the perovskite layer precursor solution (CsBr: 0.15 mol / L, PbI 2 :1mol / L, FAI: 0.85mol / L, NH 4 Cl: 0.3mol / L), the solvent is DMF. Take 50μL of perovskite precursor solution and evenly spread it on the nitrogen-doped nickel oxide hole transport layer. The parameters of the spin coater are set to acceleration 500rpm / s, rotation speed 3500rpm, and time 40s during spin coating. Then transfer the spin-coated wet film to a vacuum device, quickly evacuate to below 20Pa and keep it for 20s, then take out the film, place the film on a 160℃ hot stage for annealing for 2min, and then transfer the film to a 130℃ hot stage for annealing for 15min to obtain a perovskite film (380nm); evaporate a layer of C60 electron transport layer (40nm) on the surface of the perovskite film prepared above.

[0044] The product obtained in step (3) was transferred to a thermal evaporation device and the vacuum degree reached 1×10 -5 Under the condition of Pa, an electrode (Au) was evaporated on the C60 electron transport layer with a thickness of 100 nm to obtain a perovskite solar cell.

[0045] Example 2

[0046] (1) 3*3cm 2The ITO substrate was cleaned, a 10 g / ml nano nickel oxide aqueous solution was prepared, ultrasonic dispersion was performed for 10 min, and a NiO film was scraped on the surface of the ITO substrate by a scraping method (scraping speed 5 mm / s); and dried on a hot stage at 100° C. for 10 min to obtain an undoped nickel oxide charge transport layer with a thickness of 40 nm.

[0047] (2) The undoped nickel oxide charge transport layer is placed in a heat treatment furnace, ammonia gas is introduced into the heat treatment furnace, the pressure is maintained at 1.1tm, the atmosphere in the furnace is kept stable, the heat treatment furnace is heated to 300°C and kept warm for 8 hours to obtain a nitrogen-doped nickel oxide hole transport layer, and the sample is taken out after cooling.

[0048] (3) Prepare the perovskite layer precursor solution (CsBr: 0.15 mol / L, PbI 2 :1mol / L, FAI: 0.85mol / L, NH 4 Cl: 0.3mol / L), the solvent is DMF. Take 50μL of perovskite precursor solution and evenly spread it on the nitrogen-doped nickel oxide hole transport layer. The parameters of the spin coater are set to acceleration 500rpm / s, rotation speed 3500rpm, and time 40s during spin coating. Then transfer the spin-coated wet film to a vacuum device, quickly evacuate to below 20Pa and keep it for 20s, then take out the film, place the film on a 160℃ hot stage for annealing for 2min, and then transfer the film to a 130℃ hot stage for annealing for 15min to obtain a perovskite film (380nm); evaporate a layer of C60 electron transport layer (40nm) on the surface of the perovskite film prepared above.

[0049] The product obtained in step (3) was transferred to a thermal evaporation device and the vacuum degree reached 1×10 -5 Under the condition of Pa, an electrode (Au) was evaporated on the C60 electron transport layer with a thickness of 100 nm to obtain a perovskite solar cell.

[0050] Example 3

[0051] (1) 3*3cm 2 The ITO substrate was cleaned and a 30 nm undoped nickel oxide charge transport layer was prepared by magnetron sputtering.

[0052] (2) The undoped nickel oxide charge transport layer is placed in a heat treatment furnace, ammonia gas is introduced into the heat treatment furnace, the pressure is maintained at 1.1 atm, the atmosphere in the furnace is kept stable, the heat treatment furnace is heated to 450°C and kept warm for 7 hours to obtain a nitrogen-doped nickel oxide hole transport layer, and the sample is taken out after cooling.

[0053] (3) Prepare the perovskite layer precursor solution (CsBr: 0.15 mol / L, PbI 2:1mol / L, FAI: 0.85mol / L, NH 4 Cl: 0.3mol / L), the solvent is DMF. Take 50μL of perovskite precursor solution and evenly spread it on the nitrogen-doped nickel oxide hole transport layer. The parameters of the spin coater are set to acceleration 500rpm / s, rotation speed 3500rpm, and time 40s during spin coating. Then transfer the spin-coated wet film to a vacuum device, quickly evacuate to below 20Pa and keep it for 20s, then take out the film, place the film on a 160℃ hot stage for annealing for 2min, and then transfer the film to a 130℃ hot stage for annealing for 15min to obtain a perovskite film (380nm); evaporate a layer of C60 electron transport layer (40nm) on the surface of the perovskite film prepared above.

[0054] The product obtained in step (3) was transferred to a thermal evaporation device and the vacuum degree reached 1×10 -5 Under the condition of Pa, an electrode (Au) was evaporated on the C60 electron transport layer with a thickness of 100 nm to obtain a perovskite solar cell.

[0055] Comparative Example 1

[0056] The difference from Example 1 is that step (2) is not implemented, and the other steps are the same as Example 1.

[0057] Comparative Example 2

[0058] The difference from Example 3 is that step (2) is not implemented, and the other steps are the same as Example 3.

[0059] Test example

[0060] The current density-voltage (JV) curves of the solar cells prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were measured using PCE. The test was completed using a Kethley 2400 system. The test conditions were: the simulated light intensity was 100 mW·cm -2 (AM 1.5G) scanning rate is 0.1V·s -1 (step size is 0.02V, time delay is 200ms), the scanning interval is 1.2V to -0.2, and the power output of the xenon lamp is calibrated by the KG5 standard Si battery of NERL (National Renewable Energy Laboratory). The test results are shown in Table 1.

[0061] Table 1

[0062] Grouping Open circuit voltage(V) <![CDATA[Short-circuit current (Am / m 2 )]]> Fill Factor Photoelectric conversion efficiency Example 1 1.15 24.7 78.6％ 22.33％ Example 2 1.16 25.0 79.1％ 22.94％ Example 3 1.14 24.5 77.5％ 22.03％ Comparative Example 1 1.08 23.1 70.1％ 17.49％ Comparative Example 2 1.07 22.2 65.1％ 15.46％

[0063] According to Table 1, using nitrogen-doped nickel oxide as the hole transport layer of the perovskite solar cell improves the photoelectric conversion efficiency of the perovskite solar cell.

[0064] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms may be for different embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0065] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0066] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing nitrogen-doped nickel oxide, characterized in that: The following steps are involved: (1) placing the nickel oxide material in a heat treatment furnace; (2) introducing ammonia into the heat treatment furnace to maintain a stable atmosphere in the heat treatment furnace; (3) The heat treatment furnace is heated to 150-450° C. and then kept at this temperature for 5-10 hours to obtain nitrogen-doped nickel oxide.

2. The preparation method according to claim 1, characterized in that The nickel oxide material doping includes one of nickel oxide film and nano nickel oxide particles.

3. The preparation method according to claim 1, characterized in that: The nickel oxide material is doped with one or both of Mg and Zn.

4. The preparation method according to claim 1, characterized in that: The pressure in the heat treatment furnace is 1.01-1.2 atm.

5. The preparation method according to claim 4, characterized in that: The pressure in the heat treatment furnace is 1.05-1.1 atm.

6. A nitrogen-doped nickel oxide, characterized in that: The method is prepared by any one of claims 1 to 5.

7. The nitrogen-doped nickel oxide according to claim 6, characterized in that The nitrogen doping amount in the nitrogen-doped nickel oxide is 1 to 15 at %.

8. A perovskite solar cell, characterized in that: It comprises a transparent conductive oxide layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer and a back electrode which are stacked in sequence, wherein the hole transport layer is nitrogen-doped nickel oxide prepared by any preparation method described in claims 1 to 5 or the nitrogen-doped nickel oxide described in claim 6 or 7.

9. The perovskite solar cell according to claim 8, characterized in that The thickness of the hole transport layer is 20-80 nm.

10. The perovskite solar cell according to claim 9, characterized in that: Nitrogen element is uniformly doped in the hole transport layer.

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