CN104134720A - Preparation method of organic and inorganic hybridization perovskite material growing by single-source flash evaporation method and plane solar cell of material - Google Patents

Abstract

The invention relates to a preparation method of an organic-inorganic hybrid perovskite material grown by a single-source flash evaporation method and a planar solar cell, and belongs to the field of manufacturing technology of new material devices. Among them, the preparation method of organic-inorganic hybrid perovskite film is: use the solution of perovskite material as a single evaporation source, and use less than 1 second to rapidly heat the metal evaporation boat to a temperature above 1000 ° C, which can prepare a precise composition. Organic-inorganic hybrid perovskite thin films. The organic-inorganic hybrid perovskite film prepared by the single-source flash evaporation method has the characteristics of fast evaporation rate, no void in the film, and is suitable for planar devices. And TiO ₂ or ZnO is used as n-type material, Spiro-OMeTAD is used as p-type material and i-type organic-inorganic hybrid perovskite film to form a pin-type planar solar cell device. After optimizing the preparation conditions, an efficiency of 6.26% can be obtained. device.

Description

Organic-inorganic hybrid perovskite material grown by single-source flash evaporation method and its preparation method for planar solar cells

technical field

The invention relates to a preparation method of an organic-inorganic hybrid perovskite material grown by a single-source flash evaporation method and a planar solar cell, and belongs to the field of manufacturing technology of new material devices.

Background technique

In today's world, with the dwindling of earth resources and the increasing demand for energy, the energy crisis is imminent. In order to survive and develop, human beings must seek renewable clean new energy sources that can replace conventional energy sources, and one of the options is solar power generation. Solar energy has the advantages of huge storage, inexhaustibility, cleanness and pollution-free, and no geographical restrictions. It is the most important new energy source for human beings.

At present, solar cells mainly include crystalline silicon cells and thin-film solar cells, among which thin-film solar cells have become the development trend of solar photovoltaic cells due to the advantages of less production materials, low price, and good plasticity. At present, the two mainstream industrial thin-film battery materials are cadmium telluride (CdTe) and copper indium gallium selenide (CIGS), both of which contain elements (Te and In) that are scarce in the earth's crust, so they are not suitable for mass production. Recently, an organic-inorganic hybrid perovskite material thin-film solar cell represented by CH ₃ NH ₃ PbI ₃ has attracted widespread attention from the academic community. This type of organic-inorganic hybrid perovskite material contains elements that are abundant in the earth's crust, can be produced on a large scale, and is cheap. Since 2012, in the research of solar cells with CH ₃ NH ₃ PbI ₃ as the main absorption layer, its conversion efficiency has soared rapidly in just one year, breaking through 15%. As of June 2014, the verified highest efficiency can reach 17.9%. This makes this material very likely to become the mainstream thin-film solar cell material of the next generation, which has also attracted the attention of a large number of researchers at home and abroad. The preparation method of the material is mainly a chemical method. Such as spin coating method and two-step method based on spin coating method. Both methods deposit high-quality thin films in porous-based materials _TiO2 and ZnO, resulting in high efficiencies. However, it is not suitable for planar devices. The main reason is that the material is easy to condense to form large grains during post-baking and annealing, so that voids appear between the large grains. This will reduce the absorption of photons, and at the same time reduce the parallel resistance, making the device less efficient. In contrast, vacuum-based methods can significantly improve film coverage. For example, Henry Snaith can prepare a thin film without voids and small grains by using the dual-source method, but the control of the dual-source method is complicated, and two independent evaporation sources need to be able to work stably at a certain rate. In addition, in order to achieve high-quality thin films, the evaporation rate is very slow, and generally needs to be controlled within 0.5 Angstroms per second. Such low rates are not suitable for large-scale production.

Contents of the invention

In view of the defects in the prior art, the object of the present invention is to provide a method for preparing organic-inorganic hybrid perovskite materials and planar solar cells grown by single-source flash evaporation. The solution or powder of organic-inorganic hybrid perovskite material is used as the evaporation source, and the perovskite film is directly prepared by the single-source flash evaporation method as the absorbing layer of the solar cell, and the corresponding solar cell device is prepared to prepare high conversion efficiency. The organic-inorganic hybrid perovskite thin-film solar cells provide a new process.

To achieve the above object, the present invention adopts the following technical solutions:

A method for preparing an organic-inorganic hybrid perovskite material grown by a single-source flash evaporation method and a planar solar cell has the following process and steps:

a. Pretreat the transparent conductive glass;

b. Deposit n-type TiO ₂ or ZnO on transparent conductive glass, then put it on the sample stage of vacuum evaporation equipment as substrate;

c. Dissolve the organic-inorganic hybrid perovskite material in an organic solvent to prepare an organic-inorganic hybrid perovskite solution or powder;

d. Pretreat the metal evaporation boat;

e. Evenly spread the organic-inorganic hybrid perovskite solution or powder on the metal evaporation boat;

f. Under the conditions of a vacuum or an inert gas or nitrogen atmosphere in an evaporation chamber whose pressure is lower than 5×10 ^-3 Pa, the organic-inorganic hybrid perovskite is evaporated onto the substrate by a flash evaporation method to form a thin film;

g. Perform post-annealing treatment on the evaporated film;

h. Spin-coat the hole transport layer on the prepared organic-inorganic hybrid perovskite film material;

i. Evaporate electrodes to obtain planar organic-inorganic hybrid perovskite solar cells.

In the step a, the transparent conductive glass is FTO, that is, F-doped SnO ₂ ; or AZO, that is, Al-doped ZnO; or ITO, that is, Sn-doped In ₂ O ₃ ; the pretreatment step is: first use Triton to clean The glass surface, then rinse off the residual triton with deionized water, then ultrasonically clean with acetone for 15 minutes, then rinse the surface with deionized water, then ultrasonically clean with ethanol for 15 minutes, and then rinse the surface with deionized water , which is then dried; finally, the surface is treated with UV-ozone or microwave plasma.

In the step b, n-type TiO ₂ or ZnO is deposited on the transparent conductive glass, and the deposition method can be magnetron sputtering, spin coating or spraying. The resulting _TiO2 and ZnO will be used as substrates on which to deposit organic-inorganic hybrid perovskite materials.

The organic-inorganic hybrid perovskite solution or powder in the step c refers to the solution or powder of the ABX ₃ type organic-inorganic hybrid perovskite material including CH ₃ NH ₃ PbX ₃ and CH ₃ NH ₃ SnX ₃ , Wherein A refers to a positive monovalent organic small molecule group similar to CH ₃ NH ₃ , B refers to a positive divalent metal element, and X refers to a negative monovalent halogen element.

The metal evaporation boat in the step d refers to a tantalum sheet or a molybdenum sheet or a tungsten sheet. The pretreatment of the metal boat refers to cleaning the metal surface with acetone, ethanol and deionized water in sequence, and then treating the metal surface with ultraviolet ozone or plasma after drying.

Evaporating the organic-inorganic hybrid perovskite film by the flash evaporation method in the step f refers to evacuating the evaporation chamber to a pressure lower than 5×10 ^-3 Pa, continuing to maintain the pumping speed to maintain this vacuum degree, or turning off the vacuum pump Or a valve, or pass in an inert gas or nitrogen to 1-100Pa, and then apply a current of 80-250A to rapidly heat up the organic-inorganic hybrid perovskite solution or powder to 1000-1500°C in less than 1 second, and evaporate the entire The process is less than 5 seconds. The substrate is TiO ₂ or ZnO referred to in step b, and the substrate can be kept at room temperature or at a temperature of 100-150°C.

In the step g, post-annealing the vapor-deposited film refers to baking the vapor-deposited organic-inorganic hybrid perovskite film in a nitrogen atmosphere at 90-150°C for 5-40 minutes to form a dense , Well-crystallized film.

Spin-coating the hole transport layer on the prepared organic-inorganic hybrid perovskite film material in the step h refers to spin-coating Spiro-OMeTAD or P3HT on the evaporated perovskite film material as the hole transport layer superior.

Evaporating the electrode in the step i to obtain a planar organic-inorganic hybrid perovskite solar cell refers to evaporating a gold or silver electrode of a certain shape on the surface of the material after the hole transport layer is spin-coated by vacuum evaporation, Thus, a planar organic-inorganic hybrid perovskite solar cell is obtained.

Compared with the prior art, the present invention has the following significant advantages:

The present invention proposes a physical growth method with simple operation and extremely high growth rate, that is, a single-source flash evaporation method to prepare organic-inorganic hybrid perovskite film materials, and obtain high-efficiency solar cell devices. The process is simple, easy to operate, and can Good repeatability. This preparation method uses the solution of the perovskite material as the evaporation source, and forms a flat thin layer on the metal boat when vacuuming, and the prepared film surface has no voids and is uniform. The single-source flash evaporation method of the present invention belongs to a high-speed evaporation method and is easy for large-scale production. Through this method, the preparation of perovskite solar cells with an efficiency of 6.26% can be finally realized.

Description of drawings

Fig. 1 is the X-ray diffraction pattern of CH ₃ NH ₃ PbI ₃ thin film prepared by single-source flash evaporation method.

Fig. 2 is a scanning electron microscope image of a CH ₃ NH ₃ PbI ₃ thin film prepared by a single-source flash evaporation method.

Fig. 3 is a current-voltage diagram of a CH ₃ NH ₃ PbI ₃ thin-film solar cell prepared by a single-source flash evaporation method, tested under a light condition of 1.5 AM.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

Example 1

A method for preparing an organic-inorganic hybrid perovskite material grown by a single-source flash evaporation method and a planar solar cell has the following process and steps:

(1) Use the transparent conductive glass SnO ₂ :F as the deposition substrate, first use Triton to clean the surface, then rinse off the residual Triton on the surface with clean water, then use acetone to ultrasonically clean for 15 minutes, and then use deionized water Rinse the surface, then ultrasonically clean it with ethanol for 15 minutes, rinse the surface with deionized water, and dry it. Finally, UV-ozone treatment was used for 10 minutes.

(2) On the pretreated transparent conductive glass SnO ₂ :F, TiO ₂ is deposited by magnetron sputtering. In this process, high-purity TiO ₂ is used as the sputtering target, and the sputtering chamber is pumped to 5 ×10 ^-3 Pa, and then pass in Ar gas, the sputtering pressure is kept at 0.6Pa, the sputtering power is 150W, and the sputtering time is 36 minutes, a layer of 50nm thick can be deposited on the transparent conductive glass SnO ₂ :F Dense _TiO2 thin film.

(3) Put the transparent conductive glass SnO ₂ :F coated with 50nm n-type TiO ₂ on the sample stage of the vacuum evaporation equipment. Then the CH ₃ NH ₃ I and PbI ₂ powders were dissolved in ethanol at a ratio of 1.5:1 to prepare a CH ₃ NH ₃ PbI ₃ solution, wherein the mass percentage of the solution was 40%.

(4) Spread the CH ₃ NH ₃ PbI ₃ solution evenly on the molybdenum sheet. The perovskite film was evaporated by flash evaporation under the condition that the chamber pressure was lower than 5×10 ^-3 Pa and the temperature of the sample substrate was room temperature. The temperature of the perovskite material is rapidly raised to 1000°C within 1 second, the current used is 200 amperes, and the entire evaporation time is 5 seconds. The thickness of the film mainly depends on the amount of solution used and the distance between the source and the substrate. Generally, the volume of solution required for a 500nm thin film is 100 microliters, and the distance between the source and the substrate is about 12cm. Through this method, high-speed deposition of void-free perovskite thin film materials can be achieved. The structure and surface morphology of the film are shown in Figure 1 and Figure 2, respectively.

(5) Spin-coat the hole transport layer Spiro-OMeTAD on the vapor-deposited perovskite film material, and then vapor-deposit a silver electrode with a size of 0.5*1cm to complete the preparation of the perovskite solar cell.

The organic-inorganic hybrid planar solar cell prepared by the above method has a short-circuit current of 15.7 mA/cm ² , an open-circuit voltage of 820 mV, and a fill factor of 0.49 under the light conditions of 1.5 AM. The energy efficiency of 6.26%, as shown in Figure 3. The device efficiency without hole transport layer is 3.50%.

Example 2

Steps (1), (2) and (3) of this embodiment are exactly the same as in Example 1, the difference is that

(4) Spread the CH ₃ NH ₃ PbI ₃ solution evenly on the molybdenum sheet. After the pressure of the evaporation chamber is lower than 5×10 ^-3 Pa, nitrogen gas is filled to keep the pressure of the evaporation chamber at 0.6 Pa. Under the condition that the temperature of the sample substrate is room temperature, the perovskite film is evaporated by flash evaporation method. The temperature of the perovskite material is rapidly raised to 1000°C within 1 second, the current used is 230 amperes, and the entire evaporation time is 5 seconds.

(5) Spin-coat the hole transport layer Spiro-OMeTAD on the vapor-deposited perovskite film material, and then vapor-deposit a silver electrode with a size of 2*2cm to complete the preparation of the perovskite solar cell.

In the step (4), after passing nitrogen gas, a larger uniform organic-inorganic hybrid perovskite film can be obtained. In step (5), the solar cell efficiency close to that in Example 1 can be obtained by depositing a larger area of silver electrodes, which is about 6%. the

Claims (9)

1. a preparation method for single source flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, is characterized in that having following technical process and step:

A, transparent conducting glass is carried out to preliminary treatment;

B, on transparent conducting glass, deposit N-shaped TiO ₂or ZnO, then put on the sample stage of vacuum evaporation apparatus as substrate;

C, organic inorganic hybridization perovskite material is dissolved in organic solvent, is prepared into organic inorganic hybridization perovskite solution or powder;

D, evaporation of metal boat is carried out to preliminary treatment;

E, organic inorganic hybridization perovskite solution or powder are laid on evaporation of metal boat uniformly;

F, at vaporization chamber air pressure lower than 5 × 10 ^-3under the condition of the vacuum of Pa or inert gas or nitrogen atmosphere, by flash method by organic inorganic hybridization perovskite evaporation to substrate, form film;

G, the film that evaporation is completed carry out post annealed processing;

H, on the organic inorganic hybridization perovskite thin film material preparing spin coating hole transmission layer;

I, electrode evaporation, obtain plane organic inorganic hybridization perovskite solar cell.

2. the preparation method of single source according to claim 1 flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, is characterized in that, in described step a, transparent conducting glass is FTO, mixes the SnO of F ₂; Or AZO, mix the ZnO of Al; Or ITO, mix the In of Sn ₂o ₃; Pre-treatment step is: first adopt Qu Latong to clean glass surface, then with deionized water, the remaining Qu Latong in surface is rinsed out, adopt afterwards acetone ultrasonic cleaning 15 minutes, then use deionized water rinsing surface, use again afterwards ethanol ultrasonic cleaning 15 minutes, use again deionized water rinsing surface, subsequently by its oven dry; Finally adopt UV ozone or Microwave plasma treatment surface.

3. the preparation method of single source according to claim 1 flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, is characterized in that, deposits N-shaped TiO in described step b on transparent conducting glass ₂or ZnO, deposition process adopts magnetron sputtering method, spin coating or spray-on process; The TiO of gained ₂to use as substrate with ZnO, deposit organic inorganic hybridization perovskite material thereon.

4. the preparation method of single source according to claim 1 flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, is characterized in that, in described step c, organic inorganic hybridization perovskite solution or powder refer to and comprise CH ₃nH ₃pbX ₃and CH ₃nH ₃snX ₃at interior ABX ₃solution or the powder of type organic inorganic hybridization perovskite material, wherein A refers to similar CH ₃nH ₃positive monovalence organic molecule group, B is the divalent metal element of making a comment or criticism, X refers to negative monovalence halogen.

5. the preparation method of single source according to claim 1 flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, is characterized in that, in described steps d, evaporation of metal boat refers to tantalum piece or molybdenum sheet or tungsten sheet; Evaporation of metal boat is carried out to preliminary treatment, refer to and first adopt acetone, ethanol and deionized water to clean successively to metal surface, dry up rear with UV ozone or plasma treatment metal surface.

6. the preparation method of single source according to claim 1 flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, it is characterized in that, in described step f, refer to vaporization chamber air pressure is evacuated to lower than 5 × 10 by flash method evaporation organic inorganic hybridization perovskite thin film ^-3pa, continue to keep pumping speed to keep this vacuum degree, or close vacuum pump or valve, or pass into inert gas or nitrogen to 1-100Pa, then load 80-250A electric current, organic inorganic hybridization perovskite solution or powder are rapidly heated to 1000-1500 DEG C within the time that is less than 1 second, and whole evaporation process is less than 5 seconds.

7. the preparation method of single source according to claim 1 flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, it is characterized in that, the film in described step g, evaporation being completed carries out post annealed processing and refers to that organic inorganic hybridization perovskite thin film that evaporation is completed toasts 5-40 minute under the condition of nitrogen atmosphere and 90-150 DEG C, forms film fine and close, well-crystallized.

8. the preparation method of single source according to claim 1 flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, it is characterized in that, in described step h, on the organic inorganic hybridization perovskite thin film material preparing, spin coating hole transmission layer refers to Spiro-OMeTAD or P3HT is spin-coated on as hole transmission layer on the perovskite thin film material that evaporation completes.

9. the preparation method of single source according to claim 1 flash method growth organic inorganic hybridization perovskite material and plane solar cell thereof, it is characterized in that, electrode evaporation in described step I, obtain plane organic inorganic hybridization perovskite solar cell and refer to the material surface after spin coating hole transmission layer, by gold or the silver electrode of the method evaporation definite shape of vacuum evaporation, thereby obtain plane organic inorganic hybridization perovskite solar cell.