CN104934503A - Preparation method of perovskite solar cell light absorption layer material methylamine lead dibromide - Google Patents

Abstract

The invention relates to a preparation method of a perovskite solar cell light absorption layer material methylamine lead dibromide. The preparation method comprises the following steps: mixing solid methyl ammonium bromide and solid lead dibromide, adding the mixture into a N,N-dimethyl formamide solvent, stirring uniformly to obtain a reaction solution, pouring the reaction solution in a container, applying a pulse electromagnetic field to treat the reaction solution, dropwise adding the treated reaction solution on a clean conducting glass substrate, performing low-speed spin coating and high-speed spin coating respectively to form a perovskite film with the thickness of 500-800 nm, then putting the perovskite film in a vacuum drying oven, and performing annealing treatment to obtain a methylamine lead dibromide film. The preparation method has the advantages that the preparation technology is simple, the preparation cost is low, the degree of crystallinity of the product can be improved by adopting the treatment of the pulse electromagnetic field, and the heat preservation time of annealing treatment is greatly shortened and is only 1/6 of that when the treatment of the pulse electromagnetic field is unadopted, so that the production cycle of the product is shortened, the energy resources are saved, and the preparation method is beneficial for industrial production.

Description

A kind of preparation method of perovskite solar cell light absorption layer material methylamine lead bromide

technical field

The invention belongs to the field of solar cell material preparation, and relates to a method for preparing high-crystallinity perovskite solar cell absorbing layer material methylamine lead bromide, in particular to a method for preparing high-crystallinity perovskite by using a pulsed electromagnetic field auxiliary solution method Method for mining solar cell absorbing layer material methylamine lead bromide.

Background technique

With the depletion of energy and the deterioration of the environment, people urgently need to find a new type of clean energy that can replace traditional fossil energy. Solar energy has the advantages of sustainability and pollution-free, and is an important part of the sustainable development energy strategy of countries around the world. Solar cells are The main means of utilizing solar energy at present. At present, solar cells are mostly second-generation monocrystalline silicon or polycrystalline silicon solar cells, which have long production cycles and high costs. At the same time, there are problems such as high energy consumption and environmental pollution during the preparation of crystalline silicon. Perovskite solar cell is a new type of solar cell. The principle of this cell is different from the traditional crystalline silicon and thin film cells based on pn junction. It has the advantages of high efficiency, low cost, and simple preparation. At the same time, its cell efficiency continues to increase rapidly. , The cell efficiency of perovskite solar cells has increased from 3.8% in 2009 to 20.2% in 2015. Perovskite solar cells are a new type of solar cells with great development potential.

Organic-inorganic hybrid perovskite materials are an important part of perovskite solar cells, which act as part of the light-absorbing layer of the cell and have bipolar (electron and hole) transport functions. The light absorption layer of perovskite solar cells usually adopts methylamine lead iodide (CH ₃ NH ₃ PbI ₃ ) or methylamine lead bromide (CH ₃ NH ₃ PbBr ₃ ) with a perovskite structure of ABX3, which The source is wide, the price of raw materials is low, and flexible batteries can be prepared. At present, the methods for preparing perovskite materials mainly include solution method and co-evaporation method, but it is difficult to obtain a perovskite absorbing layer with high crystallinity by a single solution method, although co-evaporation method can obtain perovskite absorbing layer with high crystallinity layer, but the preparation cost is high, and the above problems prevent large-scale commercial production of perovskite cells. Therefore, how to obtain a low-cost, high-crystalline perovskite absorber layer is the focus of current research on perovskite solar cells.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing methylamine lead bromide, a high-crystallinity perovskite solar cell absorbing layer material, which has a simple preparation process, low preparation cost, and can increase the crystallinity of the product.

Technical solution of the present invention is:

A kind of preparation method of high crystallinity perovskite solar cell absorption layer material methylamine lead bromide, its specific steps are as follows:

(1) Clean the substrate

Use FTO conductive glass as the substrate, wash it with acetone and absolute ethanol, rinse it with deionized water, and dry it;

(2) Preparation of reaction solution

Mix solid methylammonium bromide (CH ₃ NH ₃ Br ) and solid lead bromide (PbBr ₂ ), add to N,N-dimethylformamide (DMF) solvent, and stir evenly to obtain a reaction solution , the molar ratio of methyl ammonium bromide to lead protobromide is 1:2 to 2:1, and the molar volume ratio of methyl ammonium bromide to N,N-dimethylformamide is 1:1mol /L～1:2mol/L;

(3) Pulse electromagnetic field treatment

Pour the reaction solution prepared in step (2) into a container, apply a pulse electromagnetic field to process the reaction solution, apply a pulse time of 2min to 3min, a pulse voltage of 500v to 700v, and a pulse frequency of 3Hz to 5Hz;

(4) Spin coating film formation

Add the pulse-treated reaction solution dropwise on the conductive glass substrate, and perform low-speed spin coating and high-speed spin coating respectively to form a layer of perovskite film with a thickness of 500nm-800nm, wherein the rotation number of low-speed spin coating is 800r/ min～1200r/min, the spin coating time is 20s～30s; the rotation speed of high speed spin coating is 2500r/min～3500r/min, and the spin coating time is 30s～40s;

(5) Annealing treatment

Put the spin-coated liquid film in step (4) into a vacuum drying oven, heat to 70° C. to 80° C., and keep it warm for 20 minutes to 30 minutes to obtain a methylamine lead bromide thin film.

The thickness of the FTO conductive glass is 3mm-5mm.

When cleaning the FTO conductive glass substrate, first clean it ultrasonically in acetone for 10min-20min, and then clean it in absolute ethanol for 10min-20min.

Beneficial effects of the present invention:

(1) The organic-inorganic hybrid material of methylamine lead bromide prepared by pulse electromagnetic technology has the advantages of high crystallinity, high purity and compactness; the thermogravimetric analysis data shows that the methylamine bromide after pulse treatment The decomposition temperature of the lead-organic-inorganic hybrid material increased from 375°C to 381°C, and the UV-visible spectrometer data showed that the light absorption width increased from 300nm-674nm to 300nm-685nm. The material has better stability and light absorption properties, and is assembled into perovskite Mineral solar cells are beneficial to improve battery efficiency and stability.

(2) Pulse electromagnetic field technology has low energy consumption, simple system operation, low operating cost, small equipment footprint, easy adjustment of parameters, and no pollution to the objects it processes and the surrounding environment. It is a relatively clean and environmentally friendly processing method ;After using pulsed electromagnetic field treatment, the holding time of annealing treatment is greatly shortened, and the holding time of annealing treatment is only 1/6 of that without pulsed electromagnetic field treatment, thereby shortening the production cycle of products, saving energy, and is conducive to industrial production .

Description of drawings

Fig. 1 is the XRD spectrum of the methylamine lead bromide (CH ₃ NH ₃ PbBr ₃ ) hybrid material prepared by the present invention (corresponding to Example 1 to Example 3);

Fig. 2 is an XRD spectrum of a methylamine lead bromide (CH ₃ NH ₃ PbBr ₃ ) hybrid material prepared by a common liquid phase method (corresponding to Comparative Example 1).

Detailed ways

Example 1

(1) Clean the substrate

Use FTO conductive glass with a thickness of 3mm as the substrate, first ultrasonically clean it in acetone for 10 minutes, then clean it in absolute ethanol for 10 minutes, finally rinse it with deionized water, and dry it;

(2) Preparation of reaction solution

Take 0.01mol of solid methylammonium bromide (CH ₃ NH ₃ Br ) and 0.02mol of solid lead bromide (PbBr ₂ ), add 20mL of N,N-dimethylformamide (DMF) solution, stir until solid The powder is all dissolved to obtain a reaction solution;

(3) Pulse electromagnetic field treatment

Pour the reaction solution prepared in step (2) into a beaker, and apply a pulse voltage of 500v to the reaction solution, and a pulse electromagnetic field treatment with an electric pulse frequency of 3Hz for 3min;

(4) Spin coating film formation

Add the pulse-treated reaction solution dropwise on the conductive glass substrate, and perform low-speed spin-coating and high-speed spin-coating with a homogenizer to form a perovskite film with a thickness of 500nm-600nm. The speed is 800r/min, and the spin coating time is 30s; the rotation speed of high-speed spin coating is 2500r/min, and the spin coating time is 40s;

(5) Annealing treatment

Put the spin-coated liquid film in step (4) into a vacuum drying oven, heat it to 70°C, and keep it warm for 20 minutes to obtain a methylamine lead bromide (CH ₃ NH ₃ PbBr ₃ ) film, and its XRD pattern is shown in the figure 1, it can be seen from the figure that it is obvious that the intensity of the diffraction peaks is relatively high, and the relative intensity of the diffraction peaks of the main diffraction planes (110) and (220) is about 11000-14000; through XRD calculation, the grain size is about 96nm ; By thermogravimetric analysis, its decomposition temperature is 381°C; by ultraviolet-visible spectrometer detection, it shows that the absorption width is 300nm-685nm.

Example 2

(1) Clean the substrate

Use FTO conductive glass with a thickness of 4mm as the substrate, first ultrasonically clean it in acetone for 15 minutes, then clean it in absolute ethanol for 15 minutes, and finally rinse it with deionized water and dry it;

(2) Preparation of reaction solution

Take 0.01mol of solid methylammonium bromide (CH ₃ NH ₃ Br ) and 0.01mol of solid lead bromide (PbBr ₂ ), add 15mL of N,N-dimethylformamide (DMF) solution, and stir until The solid powder is all dissolved to obtain a reaction solution;

(3) Pulse electromagnetic field treatment

Pour the reaction solution prepared in step (2) into a beaker, and apply a pulse voltage of 600v to the reaction solution, and a pulse electromagnetic field with an electric pulse frequency of 4Hz for 150s;

(4) Spin coating film formation

Add the pulse-treated reaction solution dropwise on the conductive glass substrate, and perform low-speed spin-coating and high-speed spin-coating with a homogenizer to form a perovskite film with a thickness of 600nm-700nm. The speed is 1200r/min, and the spin coating time is 20s; the rotation speed of high-speed spin coating is 3500r/min, and the spin coating time is 30s;

(5) Annealing treatment

Put the spin-coated liquid film in step (4) into a vacuum drying oven, heat to 75° C., and keep it warm for 25 minutes to obtain a methylamine lead bromide film, and its XRD pattern is shown in Figure 1; by thermogravimetric analysis , its decomposition temperature is 381°C; it is detected by UV-Vis spectrometer, and its absorption width is 300nm-685nm.

Example 3

(1) Clean the substrate

Use FTO conductive glass with a thickness of 5mm as the substrate, first ultrasonically clean it in acetone for 20 minutes, then clean it in absolute ethanol for 20 minutes, and finally rinse it with deionized water and dry it;

(2) Preparation of reaction solution

Take 0.02mol of solid methylammonium bromide (CH ₃ NH ₃ Br ) and 0.01mol of solid lead bromide (PbBr ₂ ), add 20mL of N,N-dimethylformamide (DMF) solution, and stir until The solid powder is all dissolved to obtain a reaction solution;

(3) Pulse electromagnetic field treatment

Pour the reaction solution prepared in step (2) into a beaker, and apply a pulse voltage of 700v to the reaction solution, and a pulse electromagnetic field treatment with an electric pulse frequency of 5Hz for 2min;

(4) Spin coating film formation

Add the pulse-treated reaction solution dropwise on the conductive glass substrate, and perform low-speed spin-coating and high-speed spin-coating respectively with a homogenizer to form a perovskite film with a thickness of 700nm-800nm. The speed is 1000r/min, and the spin coating time is 25s; the rotation speed of high-speed spin coating is 3000r/min, and the spin coating time is 35s;

(5) Annealing treatment

Put the spin-coated liquid film in step (4) into a vacuum drying oven, heat to 80° C., and keep it warm for 30 minutes to obtain a methylamine lead bromide film, the XRD pattern of which is shown in Figure 1; by thermogravimetric analysis , its decomposition temperature is 381°C; it is detected by UV-Vis spectrometer, and its absorption width is 300nm-685nm.

Comparative example 1

(1) Clean the substrate

Use FTO conductive glass with a thickness of 4mm as the substrate, first ultrasonically clean it in acetone for 15 minutes, then clean it in absolute ethanol for 15 minutes, and finally rinse it with deionized water and dry it;

(2) Preparation of reaction solution

Take 0.01mol of solid methylammonium bromide (CH ₃ NH ₃ Br ) and 0.01mol of solid lead bromide (PbBr ₂ ), add 15mL of N,N-dimethylformamide (DMF) solution, and stir until The solid powder is all dissolved to obtain a reaction solution;

(3) Spin coating film formation

Add the reaction solution dropwise on the conductive glass substrate, and perform low-speed spin-coating and high-speed spin-coating respectively with a homogenizer to form a perovskite film with a thickness of 700nm-800nm, wherein the rotation number of the low-speed spin-coating is 1000r/ min, the spin-coating time is 25s; the rotation speed of high-speed spin-coating is 3000r/min, and the spin-coating time is 35s;

(4) Annealing treatment

The spin-coated liquid film in step (3) was put into a vacuum drying oven, heated to 70° C., and kept for 2 hours to obtain a methylamine lead bromide (CH ₃ NH ₃ PbBr ₃ ) film. Its XRD spectrum is shown in Figure 2, as can be seen from the figure, the diffraction peak intensity of this product is lower than that of the product obtained by pulse processing in Figure 1, wherein the diffraction peaks of the main diffraction surfaces (110) and (220) The relative intensity of the peak is about 3800-5000; by XRD calculation, the crystal grain size is about 53nm; by thermogravimetric analysis, the decomposition temperature is 375°C; by ultraviolet-visible spectrometer detection, the absorption width is 300nm-674nm.

Can be obtained by comparing Fig. 1 and Fig. 2, the grain size of the product of embodiment 1～embodiment 3 of the present invention is far greater than the grain size of the product prepared by common liquid phase method (comparative example 1), thus can know, adopt pulse The crystallinity of products prepared by electromagnetic field technology has been greatly improved.

The above are only specific embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (3)

1. a preparation method for perovskite solar cell light absorption layer material methyl amine lead bromide, is characterized in that:

Concrete steps are as follows:

(1) substrate is cleaned

Using FTO electro-conductive glass as substrate, after acetone and washes of absolute alcohol, cleaner with deionized water rinsing, dry;

(2) reaction solution is prepared

Solid methyl ammonium bromide and solid brominated sub-lead are mixed, join N, in dinethylformamide solvent, stir, obtain reaction solution, the mol ratio of described methyl bromide ammonium and protobromide lead is 1:2 ~ 2:1, and described methyl bromide ammonium is 1:1mol/L ~ 1:2mol/L with the molal volume ratio of DMF;

(3) pulse electromagnetic field process

Pour in container by the reaction solution that step (2) prepares, apply pulse electromagnetic field and carry out processing reaction solution, apply burst length 2min ~ 3min, pulse voltage is 500v ~ 700v, and pulse frequency is 3Hz ~ 5Hz;

(4) spin-coating film

Reaction solution through burst process is dripped on electro-conductive glass substrate, carry out low speed spin coating and high speed spin coating respectively, forming a layer thickness is the perovskite thin film of 500nm ~ 800nm, wherein, the revolution of low speed spin coating is 800r/min ~ 1200r/min, and spin-coating time is 20s ~ 30s; The revolution of high speed spin coating is 2500r/min ~ 3500r/min, and spin-coating time is 30s ~ 40s;

(5) annealing in process

Liquid film good for spin coating in step (4) is put into vacuum drying chamber, is heated to 70 DEG C ~ 80 DEG C, insulation 20min ~ 30min, obtains methyl amine lead bromide film.

2. the preparation method of perovskite solar cell light absorption layer material methyl amine lead bromide according to claim 1, is characterized in that: the thickness of described FTO electro-conductive glass is 3mm ~ 5mm.

3. the preparation method of perovskite solar cell light absorption layer material methyl amine lead bromide according to claim 1, it is characterized in that: during cleaning FTO electro-conductive glass substrate, first ultrasonic cleaning 10min ~ 20min in acetone, then 10min ~ 20min is cleaned in absolute ethyl alcohol.