CN108365105A - A kind of perovskite solar cell and preparation method thereof - Google Patents

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof. A perovskite solar cell is characterized in that it includes a substrate, a transparent conductive layer, a hole transport layer, a light absorbing layer, an electron transport layer, and a top electrode stacked in sequence; wherein the substrate is made of glass or flexible plastic materials Made; the transparent conductive layer is a transparent electrode, and the transparent conductive layer is integrated with the substrate; the hole transport layer is an organic material or an inorganic material, which is used to transport holes to the transparent electrode; the light-absorbing layer has a perovskite structure The photovoltaic material is used to absorb incident light; the electron transport layer is a material with excellent electron conduction effect such as metal oxide, PCBM, C ₆₀ , etc., which is used to transmit electrons and isolate the light absorbing layer from the top electrode; the top electrode is a material with A material with a higher work function; the present invention also provides a method for preparing the perovskite solar cell; the present invention improves the short-circuit current and energy conversion efficiency of the perovskite solar cell.

Description

A kind of perovskite solar cell and preparation method thereof

technical field

The invention relates to the field of preparation of perovskite solar cells, in particular to a perovskite solar cell and a preparation method thereof.

Background technique

Due to the increasingly serious energy crisis, the utilization of solar energy has attracted great attention due to the cleanliness and high usage of photovoltaic technology. Organometal halide perovskite solar cells have been widely studied due to the unique properties of perovskite materials, such as high absorption coefficient and large carrier diffusion length, low-cost fabrication process and high power conversion efficiency. The energy conversion efficiency of PSC (Perovskite Solar Cells, perovskite solar cells) has risen from 3.8% first reported in 2009 to 22.1% recently. These advantages make PSCs in a prominent position in many photovoltaic technologies.

As far as the preparation of perovskite thin films is concerned, high-quality thin films can be obtained by using thermal evaporation techniques. However, the solution-based preparation is low-cost and compatible with flexible technology, so it is more promising in application. Compared with the two-step continuous solution deposition method, the one-step solution deposition method is technically simple and time-saving, thus, it is widely used to prepare perovskite thin films. However, the perovskite thin films prepared by the one-step method have smaller grain size and low coverage on the substrate. The physical processes such as the generation and transport of carriers that are very important for perovskite devices occur inside the perovskite film. Therefore, the morphology of the perovskite film greatly affects the performance of PSCs.

An ideal perovskite light-absorbing layer should have the characteristics of uniform large grains, high coverage and smooth surface. Many research efforts have focused on improving the morphology of perovskite materials, for example, selecting high-boiling point solvents to configure perovskite precursor solutions, slowing down the evaporation of solvents to reduce the growth rate of perovskite grains, and improving the grain size. Size and uniformity; improve the morphology of the perovskite layer by optimizing the interface properties of the hole transport layer or the hole transport layer/perovskite layer; by spin-coating the perovskite precursor solution at high temperature on the hot substrate On the other hand, a perovskite film with large grains is obtained; post-annealing the perovskite film with solvent vapor helps to heal the grain boundary and increase the grain size. Another widely used method is anti-solvent washing (ASW) during spin-coating of perovskite precursor solution, which is simple in process and can effectively improve the morphology of perovskite. Traditionally, the morphology of the ideal perovskite layer that can realize high-efficiency perovskite solar cells is intuitively represented as a dark brown film with a smooth surface.

Contents of the invention

The purpose of the present invention is to provide a perovskite solar cell and a preparation method thereof for the technical problems existing in the prior art, and the specific technical scheme is as follows:

In one aspect, a perovskite solar cell is provided, comprising a substrate, a transparent conductive layer, a hole transport layer, a light absorbing layer, an electron transport layer, and a top electrode stacked in sequence;

Wherein, the substrate is made of glass or flexible plastic material; the transparent conductive layer is a transparent electrode, and the transparent conductive layer is integrated with the substrate; the hole transport layer is made of organic material or Inorganic materials for transporting holes to the transparent electrodes; the light-absorbing layer is a photovoltaic material with a perovskite structure for absorbing incident light; the electron-transporting layer is metal oxide, PCBM, C ₆₀ , etc. A material with excellent electron conduction effect is used to transport electrons and isolate the light absorbing layer from the top electrode; the top electrode is a material with a higher work function.

Further, the transparent electrode is indium tin oxide (ITO), fluorine tin oxide (FTO) or aluminum zinc oxide (AZO).

Further, the thickness of the hole transport layer is 50nm~300nm; the inorganic material is a metal oxide, and the organic material is PEDOT:PSS, Spiro-MeOTAD, PTAA, P3HT, NPB, etc.

Further, the thickness of the light-absorbing layer is 200nm-400nm, and is composed of dense grains of perovskite material.

Further, the electron transport layer has a thickness of 10 nm to 100 nm.

Further, the top electrode can be made of gold, silver, copper, aluminum and other metals and conductive carbon materials.

In another aspect, a method for preparing a perovskite solar cell is provided, for preparing the above perovskite solar cell, the method comprising the steps of:

The substrate is ultrasonically cleaned for a preset time in deionized water, acetone and ethanol in sequence, dried and cleaned for a preset time by ozone plasma;

Prepare a hole transport layer film on the substrate by spin coating, and perform high temperature annealing on the formed film at 100°C to form a hole transport layer with a preset thickness;

Spin-coating a precursor solution on the hole transport layer, and dropping a quantitative amount of anti-solvent through a dropper during the spin-coating process to form a light-absorbing layer;

Forming an electron transport layer on the light absorbing layer by spin coating, and placing the electron transport layer on a hot stage at 70°C for annealing;

The substrate with the hole transport layer, the light absorbing layer and the electron transport layer stacked in sequence is placed in a vacuum plating chamber with a set vacuum degree to deposit the top electrode by thermal evaporation.

Further, the substrate is ultrasonically cleaned in the deionized water, acetone, and ethanol for 10 minutes to 20 minutes each, and cleaned in the ozone plasma for 3 minutes to 5 minutes.

Further, the preparation of the light-absorbing layer includes a first stage: spin-coating the precursor solution at a speed of 900rpm-1100rpm, and a second stage: adding anti-solvent dropwise at a speed of 4000rpm-6000rpm.

Further, the angle between the dropper and the substrate is kept at 40°-50°.

In the present invention, the light-absorbing layer in the perovskite solar cell is prepared using a photovoltaic material with a perovskite structure. In the preparation of the light-absorbing layer, a spin-coating method is used, and an anti-solvent cleaning process is used during the spin-coating process to finally obtain Different from the white mirror film layer of the traditional brown film layer, that is, the light-absorbing layer; compared with the prior art, the beneficial effect of the present invention is: the white mirror film layer formed in the present invention has a multi-layer laminated structure, and there are fewer levels Grain boundary; it is conducive to the transport of carriers, and achieves the effect of improving the short-circuit current and energy conversion efficiency of perovskite solar cells.

Description of drawings

Fig. 1 is the structural composition schematic diagram of perovskite solar cell of the present invention;

Fig. 2 is a block diagram of the preparation process of the perovskite solar cell of the present invention;

Fig. 3 is a comparison schematic diagram of the preparation process of the light-absorbing layer film of the present invention and the traditional light-absorbing layer film preparation process;

Fig. 4 is the comparative representation of the perovskite film photo in the light absorbing layer of the present invention and the perovskite film photo in the traditional light absorbing layer;

Fig. 5 SEM topography diagram of the perovskite thin film in the light-absorbing layer of the present invention and the comparison diagram of the SEM topography of the perovskite thin film in the traditional light-absorbing layer

6 is a schematic diagram of the voltage-current density test curves of the perovskite solar cell of the present invention and the traditional perovskite solar cell.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments, and the preferred embodiments of the present invention are shown in the accompanying drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein, on the contrary, these embodiments are provided for the purpose of making the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Referring to Fig. 1, in an embodiment of the present invention, on the one hand, a perovskite solar cell is provided, and the cell includes a substrate 1, a transparent conductive layer 2, a hole transport layer 3, a light absorbing layer 4, an electron transport Layer 5 and top electrode 6; wherein, the substrate 1 is made of glass or flexible plastic materials; the transparent conductive layer 2 is a transparent electrode, and the transparent electrode is indium tin oxide (ITO), fluorine tin oxide (FTO) or Aluminum zinc oxide (AZO), and the transparent conductive layer 2 is integrated with the substrate 1; the hole transport layer 3 is an organic material or an inorganic material, used to transport holes to the transparent electrode, specifically, the hole transport layer The thickness of 3 is 50nm~300nm, the inorganic materials are metal oxides, such as CuO, NiO ₂ , CuO, etc., and the organic materials are PEDOT:PSS, Spiro-MeOTAD, PTAA, P3HT, NPB, etc.; the light-absorbing layer 4 has a perovskite structure The photovoltaic material is used to absorb incident light. The thickness of the light-absorbing layer 4 is 200nm~400nm, and it is composed of dense grains of perovskite materials, specifically methyl lead triiodide perovskite CH ₃ NH ₃ PbI ₃ (MAPbI ₃ ), the surface is a white mirror; the electron transport layer 5 is a material with excellent electron conduction effect such as metal oxide, PCBM, C ₆₀ , etc., which is used to transport electrons and isolate the light absorbing layer 4 and the top electrode 6, and the electron transport layer 5 The thickness of the top electrode 6 is 10nm~100nm; the top electrode 6 is a material with a relatively high work function, which can be gold, silver, copper, aluminum and other metals and conductive carbon materials.

In conjunction with Fig. 6, it is a schematic diagram of the voltage-current density comparison curve between the perovskite solar cell of the present invention and the perovskite solar cell in the prior art, from which it can be clearly seen that compared with the existing perovskite solar cell Battery, the perovskite solar cell provided by the invention has higher short-circuit current and energy conversion efficiency.

On the other hand, referring to FIG. 2, an embodiment of the present invention provides a method for preparing a perovskite solar cell, which is used to prepare the above-mentioned perovskite solar cell. The method includes the steps of:

S1: The substrate is ultrasonically cleaned for a preset time in deionized water, acetone and ethanol in sequence, dried and cleaned by ozone plasma;

In the embodiment of the present invention, in order to ensure that the prepared perovskite solar cell has good performance, the substrate needs to be cleaned before preparation. Specifically, the substrate 1 is also provided with a layer of transparent electrodes; The substrate 1 of the electrode is put into deionized water, acetone and ethanol to carry out ultrasonic cleaning operation sequentially, and each cleaning agent needs to be cleaned for 10min~20min, which can be selected according to the actual situation; in this embodiment, preferably The cleaning time is 20 minutes; after cleaning, put it into a vacuum environment for drying treatment to remove detergent; finally, perform another 3~5min cleaning operation through ozone plasma to remove organic impurities on the surface, after drying treatment and ozone plasma After the body is processed, it is beneficial to the subsequent preparation of the hole transport layer 3 .

Preferably, in this embodiment, the thickness of the transparent conductive layer 2 is 150nm-200nm.

S2: Prepare a hole transport layer film on the substrate by spin coating, and perform high-temperature annealing on the formed film at 100°C to form a hole transport layer with a preset thickness;

Specifically, after ultrasonic cleaning, drying and ozone plasma cleaning are performed on the substrate 1, the hole transport layer 3 is prepared on the transparent conductive layer 2 by spin coating; in this embodiment, the PEDOT:PSS solution is spin-coated As an example, where the speed of spin coating is 2000rpm, the PEDOT:PSS solution can be uniformly formed a thin film layer on the transparent conductive layer 2 by spin coating; 20 minutes of high-temperature annealing treatment finally forms the preferred hole transport film layer of the present invention with a thickness of 20 nm.

S3: spin-coating a precursor solution on the hole transport layer, and dropping a quantitative amount of anti-solvent through a dropper during the spin-coating process to form a light-absorbing layer;

In this embodiment, the hole transport layer 4 is prepared from a combination of a precursor solution and an anti-solvent. The specific preparation is as follows: first, take a preset amount of precursor solution, preferably, MAPbI ₃ is selected as the Spin-coat the prepared precursor solution on the hole transport layer 3 at a speed of 900rpm~1100rpm, and after 15s, adjust the spin-coating speed to 4000rpm~6000rpm, and pass in the MAPbI ₃ precursor solution Drop the anti-solvent toluene into the dropper for washing operation, specifically: the amount of toluene dropped is 600 μl, and the dropping time is guaranteed to be 0.4s~0.6s during the dropping process, and the angle between the dropper and the substrate 1 is kept at In the range of 40°~50°, after 25s, stop the spin-coating operation to form a light-absorbing layer; similarly, perform a drying operation at the end to remove the residual solution after spin-coating.

In the present invention, the anti-solvent can be toluene, chlorobenzene, diethyl ether, etc., which are not limited and fixed in the present invention, and can be selected according to actual conditions.

Referring to Fig. 3, it is shown that the angle of the dropper and the substrate 1 is compared with the angle of the dropper and the substrate 1 in the prior art when the anti-solvent is dripped when the light-absorbing layer 4 is prepared in the present invention. The angle between the tube and the substrate 1 is 90°, and the present invention uses a dropper to form an angle of 45° with the substrate 1 to drop the antisolvent; in combination with Fig. 4 and Fig. 5 , it can be drawn that the light absorption formed by the preparation of the present invention The crystal grains in layer 4 are a multi-layered structure with fewer horizontal grain boundaries, and it is a white mirror film.

S4: forming an electron transport layer on the light absorbing layer by spin coating, and placing the electron transport layer on a hot stage at 70°C for annealing;

In this embodiment, PC ₆₁ BM is selected as the preparation material of the electron transport layer 5, and a thin film layer is formed by spin coating. Specifically, the PC ₆₁ BM material is first spin-coated at a speed of 3000 rpm for 20 seconds, and then the speed is adjusted to 6000 rpm. Spin coating for 20s. After completion, place it on a hot stage with a set temperature of 70°C for annealing treatment. The annealing time is 60 minutes. The main purpose of annealing is to remove the remaining preparation material PC ₆₁ BM and ensure dryness. On the one hand It is beneficial to the subsequent preparation of the top electrode 6, and on the other hand, can improve the performance of the final perovskite solar cell product.

S5: Place the substrate with the hole transport layer, the light absorbing layer and the electron transport layer stacked in sequence in a vacuum plating chamber with a set vacuum degree to deposit the top electrode by thermal evaporation.

After the hole transport layer, the light absorbing layer, and the electron transport layer are prepared sequentially, the top electrode 6 is finally prepared. When preparing the top electrode 6, it needs to be placed in a vacuum environment of 3*10 ^-4 Pa, and thermally evaporated 10 nm in sequence. Thick BCP and 150 nm thick Ag form the top electrode 6 with an effective area of 0.096 cm ² .

The light-absorbing layer of the perovskite solar cell finally formed by the method for preparing the perovskite solar cell provided by the present invention is a white mirror film, and the crystal grains of the white mirror film are a multi-layer laminated structure, which is beneficial to carrier transport and can improve the efficiency of the battery. Energy conversion efficiency.

In the present invention, the light-absorbing layer in the perovskite solar cell is prepared using a photovoltaic material with a perovskite structure; in the preparation of the light-absorbing layer, a spin-coating method is used, and an anti-solvent cleaning process is used during the spin-coating process to finally obtain Different from the white mirror film layer of the traditional brown film layer, that is, the light-absorbing layer; compared with the prior art, the beneficial effect of the present invention is: the white mirror film layer formed in the present invention has a multi-layer laminated structure, and there are fewer levels Grain boundary; it is conducive to the transport of carriers, and achieves the effect of improving the short-circuit current and energy conversion efficiency of perovskite solar cells.

The above are only preferred embodiments of the present invention, but do not limit the patent scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it can still be specific to the foregoing embodiments. The technical solutions described in the implementation modes shall be modified, or some of the technical features shall be replaced equivalently. All equivalent structures made by utilizing the contents of the specification and drawings of the present invention and directly or indirectly used in other related technical fields are also within the protection scope of the patent of the present invention.

Claims (10)

1. a kind of perovskite solar cell, which is characterized in that including the substrate, transparency conducting layer, hole being cascading Transport layer, light-absorption layer, electron transfer layer and top electrode；

Wherein, the substrate is made of glass or flexiplast class material；The transparency conducting layer is a transparent electrode, described Transparency conducting layer and the substrate integrated setting；The hole transmission layer is organic material or inorganic material, is used for hole It is transmitted to the transparent electrode；The light-absorption layer is the photovoltaic material with perovskite structure, for absorbing incident light；The electricity Sub- transport layer is metal oxide, PCBM, C₆₀Deng the material with excellent electronics conducting effect, it is used for transmission electronics, and be isolated The light-absorption layer and the top electrode；The top electrode is the material with higher work-functions.

2. a kind of perovskite solar cell according to claim 1, which is characterized in that the transparent electrode is indium tin oxygen Compound（ITO）, fluorine tin-oxide（FTO）Or aluminium zinc oxide（AZO）.

3. a kind of perovskite solar cell according to claim 1, which is characterized in that the thickness of the hole transmission layer For 50nm ~ 300nm；The inorganic material is metal oxide, and the organic material is PEDOT:PSS、Spiro-MeOTAD、 PTAA, P3HT, NPB etc..

4. a kind of perovskite solar cell according to claim 1, which is characterized in that the thickness of the light-absorption layer is 200nm ~ 400nm is made of the compact-grain of perovskite material.

5. a kind of perovskite solar cell according to claim 1 and preparation method thereof, which is characterized in that the electronics The thickness of transport layer is 10nm ~ 100nm.

6. a kind of perovskite solar cell according to claim 1 and preparation method thereof, which is characterized in that the top electricity Extremely can be the metals such as gold, silver, copper, aluminium and conductive carbon material.

7. a kind of preparation method of perovskite solar cell, is used to prepare the perovskite solar-electricity described in claim 1 ~ 6 Pond, which is characterized in that the method includes the steps：

Carry out the ultrasonic cleaning of preset time to substrate successively in deionized water, acetone and ethyl alcohol, drying simultaneously passes through ozone Plasma clean preset time；

Hole transport layer film is prepared using spin coating mode on substrate, and high temperature is carried out to the film of formation at 100 DEG C and is moved back Fire operation, forms the hole transmission layer of preset thickness；

Spin coating precursor solution on the hole transport layer, and in spin coating process by dropper be added dropwise quantitative anti-solvent into Row washing, forms light-absorption layer；

Electron transfer layer is formed by way of spin coating on light-absorption layer, and the electron transfer layer is placed in 70 DEG C of thermal station It is made annealing treatment；

There is the substrate of hole transmission layer, light-absorption layer, electron transfer layer to be placed on the Vacuum Deposition chamber of setting vacuum degree lamination successively Pass through thermal evaporation deposition top electrode.

8. a kind of preparation method of perovskite solar cell according to claim 7, which is characterized in that the substrate exists The ultrasonic cleaning that 10min ~ 20min is respectively carried out in the deionized water, acetone, ethyl alcohol is cleaned in the ozone plasma 3min~5min。

9. a kind of preparation method of perovskite solar cell according to claim 7, which is characterized in that the light-absorption layer Preparation include the first stage：Spin coating operation and second-order are carried out to precursor solution under 900rpm ~ 1100rpm speed Section：Anti-solvent is added dropwise under 4000rpm ~ 6000rpm speed.

10. a kind of preparation method of perovskite solar cell according to claim 7, which is characterized in that the dropper It is maintained at 40 ° ~ 50 ° with the angle of substrate.