One-dimensional perovskite thin films, methods of preparation and applications

Abstract

The application provides a one-dimensional perovskite film, a preparation method and application, relates to the technical field of perovskite films, and a preparation method of a one-dimensional perovskite film, which comprises film forming, wherein the film forming is crystallization and film forming of one-dimensional perovskite precursors in a solution with perovskite quantum dots as initial crystallization sites; and the particle size of the perovskite quantum dots is 3-10 nm. By introducing quantum dots into the one-dimensional perovskite film, the coverage and optical absorption performance of the one-dimensional perovskite film are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of perovskite thin films, in particular to a one-dimensional perovskite thin film, a preparation method and an application. BACKGROUND

[0002] In recent years, organic-inorganic hybrid perovskites have attracted extensive attention from researchers. Due to the excellent photonic absorption ability of organic-inorganic hybrid perovskites, they are often used as active layers in various optoelectronic devices such as solar cells and light-emitting diodes. In addition, high-quality perovskite thin films can be prepared by a simple solution coating process, which greatly reduces the cost of mass production of organic-inorganic hybrid perovskites. The above advantages have led to rapid progress in the academic and industrial fields of perovskites in recent years. However, the stability of commonly used three-dimensional perovskites (formamidinium lead iodide, guanidinium lead iodide, and cesium lead iodide systems) in the external environment is poor, which affects their commercialization process. In contrast, one-dimensional perovskites with excellent environmental stability provide an alternative approach.

[0003] The structural diagrams of three-dimensional perovskites and one-dimensional perovskites are shown in Figure 1 It can be seen that, compared to the "point-to-point" connection of lead iodide octahedra in three-dimensional perovskites, the octahedra in one-dimensional perovskites are connected "face-to-face". This structural feature makes one-dimensional perovskites have some special properties. Compared to three-dimensional perovskites and quantum dots, one-dimensional perovskites have high crystalline orientation (chain structure) and strong anisotropy. Therefore, it is difficult to form high-density and uniform thin films, and the large number of gaps and pores in the middle seriously reduces the photonic absorption ability, thereby greatly limiting the practical application scenarios of one-dimensional perovskites.

[0004] In the study of perovskite thin film optoelectronic devices, it is crucial to prepare perovskite thin films with high coverage and density. Because a dense perovskite thin film can first improve its optical performance and the application performance of subsequent one-dimensional perovskite devices. In addition, a dense perovskite thin film has fewer defects, which not only makes the generated carriers have a longer lifetime, but also suppresses the ion migration phenomenon in the perovskite lattice, so that the stability and lifetime of the prepared device are also better. In fact, in the study of three-dimensional perovskite solar cells, the crystallization process can be controlled by adding various additives to the perovskite precursor solution, changing the annealing temperature, annealing time, and the type of anti-solvent, etc. to improve the density of three-dimensional perovskite thin films, thereby improving the efficiency and stability of the solar cells. For one-dimensional perovskites, due to the crystalline and chain structure characteristics of one-dimensional perovskites, it is not only difficult to control the film forming performance of the thin film, but also difficult to form a thin film with high density and uniformity.

[0005] Due to the fast crystallization rate of one-dimensional perovskite and the anisotropy of the crystallization growth process, it is difficult to obtain a one-dimensional perovskite film with high density and high coverage by using the traditional method effective in three-dimensional perovskite. The crystallization characteristics make the grown one-dimensional perovskite mostly in a chain structure, so that the prepared film is prone to have gaps and holes, and the film uniformity is poor, which leads to incomplete optical absorption performance of the film, thereby affecting the subsequent application in optoelectronic devices such as solar cells, light-emitting diodes, etc.

[0006] In view of this, the present application is proposed. SUMMARY

[0007] The purpose of the present application is to provide a one-dimensional perovskite film, a preparation method and an application, so as to overcome the technical problem that in the prior art, one-dimensional perovskite is mostly in a chain structure, so that the prepared film is prone to have gaps and holes, and the film uniformity is poor, which leads to poor optical absorption performance of the film.

[0008] In a first aspect, the present application provides a preparation method of a one-dimensional perovskite film, comprising film formation, wherein the film formation is crystallization and film formation of one-dimensional perovskite precursors in a solution with perovskite quantum dots as initial crystallization sites;

[0009] The particle size of the perovskite quantum dots is 3-10 nm.

[0010] In an optional embodiment, the film formation is to spin-coat one-dimensional perovskite precursor solution on a perovskite quantum dot layer by using a spin-coating method, and then perform anti-solvent crystallization and annealing to obtain a one-dimensional perovskite film;

[0011] Preferably, the amount of one-dimensional perovskite precursor solution on the perovskite quantum dot layer is 22-45 μL / cm 2 ;

[0012] Preferably, the spin-coating comprises low-speed spin-coating and high-speed spin-coating.

[0013] Preferably, in the low-speed spin-coating, the rotation speed of the substrate is 1500-2000 rpm, the acceleration is 500-800 rpm / s 2 , and the spin-coating time is 8-10 s.

[0014] Preferably, in the high-speed spin-coating, the rotation speed of the substrate is 5000-6000 rpm, the acceleration is 1000-2000 rpm / s 2 , and the spin-coating time is 30-35 s.

[0015] In an optional embodiment, the perovskite quantum dot layer is obtained by pre-spin-coating perovskite quantum dot solution on a substrate by using a spin-coating method, and then performing annealing.

[0016] Preferably, the amount of perovskite quantum dot solution used in the pre-spin coating step is 22-45 μL / cm 2 ;

[0017] Preferably, the concentration of perovskite quantum dot solution in the pre-spin coating step is 1-20 mg / ml;

[0018] Preferably, in the pre-spin coating step, the rotation speed of the substrate is 3500-5000 rpm, the acceleration is 2000-3000 rpm / s 2 , and the spin coating time is 25-40 s.

[0019] In an optional embodiment, the film formation is to spin coat a one-dimensional perovskite precursor solution containing perovskite quantum dots on a substrate by spin coating, and then perform anti-solvent crystallization and annealing to obtain a one-dimensional perovskite film;

[0020] Preferably, the amount of one-dimensional perovskite precursor solution containing perovskite quantum dots used on the substrate is 22-45 μL / cm 2 ;

[0021] Preferably, the spin coating includes low-speed spin coating and high-speed spin coating;

[0022] Preferably, in the low-speed spin coating, the rotation speed of the substrate is 1500-2000 rpm, the acceleration is 500-800 rpm / s 2 , and the spin coating time is 8-10 s;

[0023] Preferably, in the high-speed spin coating, the rotation speed of the substrate is 5000-6000 rpm, the acceleration is 1000-2000 rpm / s 2 , and the spin coating time is 30-35 s;

[0024] Preferably, the concentration of perovskite quantum dots in the one-dimensional perovskite precursor solution containing perovskite quantum dots is 1-10 mg / ml.

[0025] In an optional embodiment, the anti-solvent crystallization is to rapidly add an anti-solvent to the substrate when the high-speed spin coating is performed for 25-30 s;

[0026] The anti-solvent is any one of chlorobenzene, diethyl ether, and acetone;

[0027] The amount of anti-solvent used is 360-450 μL / cm 2 .

[0028] In an optional embodiment, the annealing is to place the coated film substrate at a temperature of 80-200 ℃ for 10-20 min.

[0029] In an optional embodiment, the one-dimensional perovskite precursor solution is prepared by mixing A + , B 2+ , X - and a solvent;

[0030] wherein A is a heterocyclic compound in which the heteroatom is nitrogen; B is a metal; and X is a halogen;

[0031] Preferably, the heterocyclic compound is a five-membered heterocyclic ring, a six-membered heterocyclic ring or a seven-membered heterocyclic ring;

[0032] Preferably, the solvent is at least one of DMF and DMSO;

[0033] Preferably, the one-dimensional perovskite precursor solution comprises AX and BX2;

[0034] Preferably, B 2+ is Pb 2+ or Sn 2+ ; and X - is I - , Br - or Cl - ;

[0035] Preferably, the molar ratio of AX to BX2 is 0.5-5:1; and the total concentration of A, B and X in the one-dimensional perovskite precursor solution is 50-100 mg / ml;

[0036] Preferably, A + , B 2+ , X - and the solvent are mixed and heated to 50-100°C for stirring and dissolving to obtain the one-dimensional perovskite precursor solution.

[0037] In an optional embodiment, the substrate is cleaned before spin coating or pre-spin coating is performed on the substrate;

[0038] Preferably, the substrate is ITO conductive glass, FTO conductive glass or AZO conductive glass;

[0039] Preferably, the cleaning method comprises: sequentially cleaning the substrate with dishwashing liquid, deionized water and anhydrous ethanol, and then ultrasonic cleaning in a cleaning solution for more than 15 minutes; and after the ultrasonic cleaning, placing the substrate in an oven in a temperature atmosphere lower than 200°C for drying;

[0040] Preferably, the cleaning solution is at least one of anhydrous ethanol, deionized water, acetone and anhydrous ethanol;

[0041] Preferably, the dried substrate is subjected to plasma surface treatment for 5-150 seconds;

[0042] Preferably, the substrate after drying is placed in the ultraviolet-ozone environment for 1-30 minutes.

[0043] In a second aspect, the present application provides a one-dimensional perovskite film prepared according to the method of any one of the preceding embodiments.

[0044] Preferably, the one-dimensional perovskite film satisfies TF>1.0, wherein the calculation method of TF is shown in Formula 1:

[0045]

[0046] In Formula 1, r A is the radius of the A-site ion, r B is the radius of the B-site metal ion, and r X is the radius of the X-site ion.

[0047] In a third aspect, the present application provides the use of the one-dimensional perovskite film of any one of the preceding embodiments in an optoelectronic device.

[0048] The present application has the following beneficial effects:

[0049] The pure one-dimensional perovskite film has the shortcomings of poor film forming compactness and incomplete optical absorption, which greatly limits its application as an optical absorption layer. The pure quantum dot film has many grain boundaries, and the large number of defects at the interface will affect the photoelectric performance; and due to the weak interaction between quantum dots, it is not easy to prepare a film with high uniformity and good coverage. By introducing quantum dots into the one-dimensional perovskite film, the coverage and optical absorption performance of the one-dimensional perovskite film are greatly improved. The introduced quantum dots serve as initial crystal nuclei with a size much higher than the homogeneous nucleation process, and are uniformly distributed in the perovskite. Due to its high specific surface area, the perovskite precursor can be attached to each position on the surface of the quantum dot for nucleation and growth, so that the one-dimensional perovskite with high crystalline orientation and anisotropy finally generates an isotropic quantum dot modified one-dimensional perovskite film with low crystalline orientation. In addition, the problem of polycrystalline boundary of the pure quantum dot film is also improved, because the formed crystal is not only a single quantum dot, but a composite core-shell structure composed of quantum dots and one-dimensional perovskite. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0051] Figure 1A schematic diagram of a three-dimensional perovskite and a one-dimensional perovskite structure;

[0052] Figure 2 A schematic diagram of the effect of adding perovskite quantum dots on the one-dimensional perovskite film in the present application;

[0053] Figure 3 SEM results of the one-dimensional perovskite film in Example 1;

[0054] Figure 4 SEM results of the one-dimensional perovskite film in Comparative Example 2;

[0055] Figure 5 Comparison of the optical absorption results of the one-dimensional perovskite film obtained in Example 1 and Comparative Example 2. DETAILED DESCRIPTION

[0056] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0057] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0058] The embodiments of the present application provide a preparation method of a one-dimensional perovskite film, comprising film formation, wherein the one-dimensional perovskite precursor in the solution is crystallized and formed into a film with perovskite quantum dots as initial crystallization sites.

[0059] The particle size of the perovskite quantum dots is 3-10 nm.

[0060] The chain-like structure of the one-dimensional perovskite is not conducive to the formation of a high-density film. The random stacking of a large number of perovskite lines causes a large number of gaps and holes in the film. The existence of these gaps and holes causes incomplete photon absorption, which reduces the optical absorption capacity of the film and seriously affects the lifetime of photo-generated carriers, which reduces the performance of the subsequent prepared devices.

[0061] The perovskite quantum dot is a kind of spherical material, and the size thereof is generally between several nanometers and dozens of nanometers. If the size of the perovskite quantum dot is too small, the subsequent crystallization process of the perovskite has little influence, and the one-dimensional perovskite still tends to be crystallized into a chain structure. In the embodiment, the size of the perovskite quantum dot added is greater than 3 nm, which can be introduced into the one-dimensional perovskite film substrate as a new crystallization site. The uniform distribution of the quantum dot site can effectively increase the compactness and uniformity of the one-dimensional perovskite film, and the effect is as follows Figure 2 .

[0062] The optical performance of the one-dimensional perovskite film with better compactness is also improved. On the one hand, the one-dimensional perovskite material as an active layer is more uniformly covered (the substrate has much weaker absorption of photons than the perovskite layer, and the absorption of photons by the substrate can be ignored); on the other hand, the added quantum dot itself has good absorption capacity, and thus has a gain effect on the overall light absorption capacity of the film.

[0063] In the present application, the one-dimensional perovskite film satisfies TF>1.0, wherein the calculation method of TF is shown in formula 1.

[0064]

[0065] In formula 1, r A is the radius of the A-site ion, r B is the radius of the B-site metal ion (such as Pb, Sn, etc.), and r X is the radius of the X-site ion (such as I, Br, Cl). When TF is in the range of 0.8-1.0, it is considered that a three-dimensional perovskite structure is formed, and when it is out of the range, a low-dimensional perovskite such as a one-dimensional perovskite or a two-dimensional perovskite is generated. By doping the A-site ion with a larger ion radius to increase the value of TF, a one-dimensional perovskite can be obtained. It should be noted that, generally, the one-dimensional perovskite needs to satisfy TF>1.0, but it does not mean that the one-dimensional perovskite can be formed when TF>1.0. Therefore, the types of A, B and X need to be selected according to the actual situation to prepare a one-dimensional perovskite precursor solution capable of forming a one-dimensional perovskite.

[0066] By introducing quantum dots into the one-dimensional perovskite film, the coverage and optical absorption performance of the one-dimensional perovskite film are greatly improved. The introduced quantum dots, as initial crystal nuclei with a size much higher than the homogeneous nucleation process, are uniformly distributed in the perovskite. Due to the high specific surface area, the perovskite precursor can be attached to each position on the surface of the quantum dot for nucleation and growth, so that the one-dimensional perovskite with high crystalline orientation and anisotropy finally generates the quantum dot modified one-dimensional perovskite film with isotropy and low crystalline orientation. In addition, the polycrystalline boundary problem of the pure quantum dot film is also improved, because the formed crystal is not only a single quantum dot, but also a composite core-shell structure composed of quantum dots and one-dimensional perovskite.

[0067] Further, in one embodiment of the present application, the film formation is to spin-coat one-dimensional perovskite precursor solution on the perovskite quantum dot layer by spin-coating method, and then perform anti-solvent crystallization and annealing to obtain one-dimensional perovskite film.

[0068] Preferably, the amount of one-dimensional perovskite precursor solution on the perovskite quantum dot layer is 22-45 μL / cm 2 ;

[0069] Preferably, the spin-coating includes low-speed spin-coating and high-speed spin-coating.

[0070] Preferably, in the low-speed spin-coating, the rotation speed of the substrate is 1500-2000 rpm, the acceleration is 500-800 rpm / s 2 , and the spin-coating time is 8-10 s.

[0071] Preferably, in the high-speed spin-coating, the rotation speed of the substrate is 5000-6000 rpm, the acceleration is 1000-2000 rpm / s 2 , and the spin-coating time is 30-35 s.

[0072] In this embodiment, the perovskite quantum dot layer is prepared before the perovskite precursor solution is coated, which is helpful to uniformly fix the perovskite quantum dots on the substrate to form "crystal nucleus" in advance, compared with adding the perovskite quantum dots to the precursor solution and then performing film formation. In addition, since this step does not involve the one-dimensional perovskite crystallization process, the selected concentration range of the perovskite quantum dot solution is relatively wide. The perovskite precursor solution can stably and isotropically crystallize and grow with the uniformly distributed and fixed perovskite quantum dots as the crystal nucleus, which is conducive to improving the compactness of the one-dimensional perovskite film and to a certain extent, improving the light absorption capacity.

[0073] During the pre-coating process, the substrate needs to have a high rotation speed, which to a certain extent, affects the centrifugal force of the perovskite quantum dot particles in the perovskite quantum dot solution, and reduces or even avoids the agglomeration of the perovskite quantum dots in the solution.

[0074] In the present application, two-step spin-coating is defined, the first step is low-speed spin-coating, and the second step is high-speed spin-coating. On the basis of uniform coating, the crystallization process of the perovskite in the solution is affected, and the coverage and compactness of the one-dimensional perovskite film are improved.

[0075] Since the crystallization rate of one-dimensional perovskite is fast, the rotation speed of the substrate during high-speed spin-coating is 5000-6000 rpm. The reduction of the speed will reduce the uniformity of the solution film formation and the solvent evaporation rate, and the surface of the obtained film is uneven, which affects the optical absorption performance of the film.

[0076] Further, the perovskite quantum dot layer is obtained by pre-spinning a perovskite quantum dot solution on a substrate by a spin coating method, and then performing annealing;

[0077] Preferably, the amount of the perovskite quantum dot solution on the substrate in the pre-spinning step is 22-45 μL / cm 2 ;

[0078] Preferably, the concentration of the perovskite quantum dot solution in the pre-spinning step is 1-20 mg / ml.

[0079] Preferably, in the pre-spinning step, the rotation speed of the substrate is 3500-5000 rpm, the acceleration is 2000-3000 rpm / s, and the spin coating time is 25-40 s. 2

[0080] A too high concentration of the perovskite quantum dots can cause uneven distribution of the perovskite quantum dots on the substrate and easy agglomeration and stacking, affecting the subsequent one-dimensional perovskite crystallization. Similarly, a too low rotation speed can cause uneven spreading of the quantum dot solution and easy agglomeration.

[0081] Further, in another embodiment of the present application, the film formation is performed by spin coating a one-dimensional perovskite precursor solution containing perovskite quantum dots on a substrate by a spin coating method, and then performing anti-solvent crystallization and annealing to obtain a one-dimensional perovskite film;

[0082] Preferably, the amount of the one-dimensional perovskite precursor solution containing perovskite quantum dots on the substrate is 22-45 μL / cm 2 ;

[0083] Preferably, the spin coating includes low-speed spin coating and high-speed spin coating.

[0084] Preferably, in the low-speed spin coating, the rotation speed of the substrate is 1500-2000 rpm, the acceleration is 500-800 rpm / s 2 , and the spin coating time is 8-10 s.

[0085] Preferably, in the high-speed spin coating, the rotation speed of the substrate is 5000-6000 rpm, the acceleration is 1000-2000 rpm / s 2 , and the spin coating time is 30-35 s.

[0086] Preferably, the concentration of the perovskite quantum dots in the one-dimensional perovskite precursor solution containing perovskite quantum dots is 1-10 mg / ml.

[0087] Adding the perovskite quantum dots to the precursor solution and then performing film formation does not require additional processing steps, is convenient to process, saves preparation time and cost, and helps to improve the uniformity and density of the one-dimensional perovskite film while ensuring processing efficiency.​

[0088] Further, the anti-solvent crystallization is performed by rapidly dropping the anti-solvent onto the substrate when the high-speed spin coating is performed for 25-30s;

[0089] The anti-solvent is any one of chlorobenzene, diethyl ether and acetone;

[0090] The amount of the anti-solvent is 360-450 μL / cm 2 .

[0091] In the embodiment, the dropping of the anti-solvent has relatively strict requirements on the dropping time and dropping speed, i.e., there is an anti-solvent adding "window period". If the dropping time is too early, the solvent volatilization and crystallization process will be accelerated, which may cause the crystal size to be too small. If the dropping time is too late, the crystallization is mostly completed due to the late addition, which has little effect on the one-dimensional perovskite film and may cause uneven distribution of the crystal, which will affect the light absorption capacity of the film. If the dropping is too slow, the one-dimensional perovskite precursor may not be uniformly crystallized, which will affect the uniformity of the film.

[0092] Further, the annealing is performed by placing the coated film substrate at a temperature of 80-200℃ for 10-20min.

[0093] The purpose of the annealing is mainly to remove the residual solvent and to promote the completion of the crystallization. If the annealing temperature is lower than 80℃, the crystallization may not be sufficient. If the annealing temperature is higher than 200℃, the one-dimensional perovskite material may be degraded, which will cause the film to decay.

[0094] Further, the one-dimensional perovskite precursor solution is obtained by mixing A + , B 2+ , X - and a solvent;

[0095] wherein A is a heterocyclic compound, the heteroatom in the heterocyclic compound is nitrogen; B is a metal; and X is a halogen;

[0096] Preferably, the heterocyclic compound is a five-membered heterocyclic ring, a six-membered heterocyclic ring or a seven-membered heterocyclic ring;

[0097] Preferably, the solvent is at least one of DMF and DMSO;

[0098] Preferably, the one-dimensional perovskite precursor solution includes AX and BX2;

[0099] Preferably, B 2+ is Pb 2+ or Sn 2+ ; X - is I - , Br - or Cl - ;

[0100] Preferably, the molar ratio of AX and BX2 is 0.5-5:1; the concentration of the solute in the solution is 50-100 mg / ml;

[0101] Preferably, the mixture containing A + , B 2+ , X - and solvent is heated to 50-100℃ and stirred to dissolve, to obtain a one-dimensional perovskite precursor solution.

[0102] The one-dimensional perovskite precursor solution refers to a precursor solution capable of generating a one-dimensional perovskite thin film. In the present embodiment, A is limited to a heterocyclic compound, which is a five-membered heterocyclic ring, a six-membered heterocyclic ring or a seven-membered heterocyclic ring with nitrogen as the heteroatom. On the one hand, the multi-membered heterocyclic ring can increase the diameter of the cation, which is conducive to improving the TF value and promoting the formation of a one-dimensional perovskite thin film. On the other hand, the rigid structure and hydrophobic property of the multi-membered heterocyclic ring can to some extent play a stabilizing role on the perovskite precursor and the formed crystal structure. The nitrogen atom contained in the multi-membered ring can form hydrogen bonds / van der Waals bonds with halogen elements, thereby forming a stable one-dimensional perovskite structure.

[0103] Further, before performing film coating or pre-film coating on the substrate, the substrate is cleaned;

[0104] Preferably, the substrate is ITO conductive glass, FTO conductive glass or AZO conductive glass;

[0105] Preferably, the cleaning method specifically comprises: sequentially cleaning the substrate with dishwashing liquid, deionized water and anhydrous ethanol, and then ultrasonic cleaning in a cleaning solution for more than 15 min; and after the ultrasonic cleaning is completed, placing the substrate in an oven in a temperature atmosphere lower than 200℃ for drying;

[0106] Preferably, the cleaning solution is at least one of anhydrous ethanol, deionized water, acetone and anhydrous ethanol;

[0107] Preferably, the substrate after drying is subjected to plasma surface treatment for 5-150 s;

[0108] Preferably, the substrate after drying is placed in an ultraviolet-ozone environment for 1-30 min.

[0109] Another embodiment of the present application can provide a one-dimensional perovskite thin film obtained according to the preparation method of the one-dimensional perovskite thin film of any one of the preceding embodiments;

[0110] Preferably, the one-dimensional perovskite thin film satisfies TF>1.0, wherein the calculation method of TF is shown in Formula 1:

[0111]

[0112] In formula 1, r A is the radius of the A-site ion, r B is the radius of the B-site metal ion, r X is the radius of the X-site ion.

[0113] Under the action of the perovskite quantum dots, the pore size of the one-dimensional perovskite film in the embodiment can reach below 0.2 μm, and the light absorption capacity in the wavelength range of 420-525 nm can be increased by up to 14%.

[0114] Another embodiment of the present application can provide an application of the one-dimensional perovskite film in a photoelectric device, including but not limited to a solar cell, a light-emitting diode.

[0115] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the case of no conflict, the embodiments described below and the features in the embodiments can be combined with each other.

[0116] Embodiment 1:

[0117] Preparation method of one-dimensional perovskite film with quantum dots optimized buried bottom interface:

[0118] The glass substrate plated with indium tin oxide (ITO) is sequentially cleaned with detergent, deionized water and anhydrous ethanol, and then sequentially ultrasonically cleaned with anhydrous ethanol, deionized water, acetone and anhydrous ethanol for 15 min. After the ultrasonic cleaning is completed, the glass substrate is placed in a 60°C oven until it is dried. The ITO substrate after drying is subjected to plasma surface treatment for 90 s. The area of the ITO substrate is 2.25 cm 2 The ITO substrate is spin-coated with 75 μL of perovskite quantum dot solution with a concentration of 20 mg / ml and a particle size of 3-10 nm at a speed of 4000-4300 rpm for 35 s, and an acceleration of 2000 rpm / s. 2 The ITO substrate is annealed at a temperature of 150°C for 10 min.

[0119] Pyrrolidine (C4NH9) and PbI2 are placed in a reagent bottle in a molar ratio of 2.5:1, and DMF and DMSO are taken in a reagent bottle in a volume ratio of 4:1 to configure a one-dimensional perovskite precursor solution with a solution concentration of 80 mg / ml. The one-dimensional perovskite precursor solution is filtered, and 75 μL of the filtered one-dimensional perovskite precursor solution is applied to the ITO substrate. The spin-coating parameters are set on the spin coater as follows: the first step is spin-coated at a speed of 1700-1800 rpm for 9 s, and an acceleration of 650 rpm / s 2 The second step is spin-coated at a speed of 5300-5500 rpm for 33 s, and an acceleration of 1500 rpm / s 2, after setting, start spin coating, then take 900 μL chlorobenzene as anti-solvent with a pipette, and pour all the chlorobenzene on the substrate from the middle of the substrate at a high speed spin coating to 28 s.

[0120] Immediately after spin coating, place the substrate on the hot stage, and anneal at a temperature atmosphere of 150 ℃ for 15 min to obtain a one-dimensional perovskite film. Figure 3 and Figure 5 as shown.

[0121] Example 2

[0122] Preparation method of quantum dot optimized one-dimensional perovskite thin film:

[0123] The glass substrate plated with indium tin oxide (ITO) is sequentially cleaned with detergent, deionized water, and anhydrous ethanol, and then sequentially ultrasonically cleaned with anhydrous ethanol, deionized water, acetone, and anhydrous ethanol for 15 min. After ultrasonic cleaning, place it in a 60 ℃ oven until it is dried. The dried ITO substrate is subjected to plasma surface treatment for 90 s. Then a one-dimensional perovskite thin film is prepared by one-step method.

[0124] Pyrrolidine (C4NH9) and PbI2 are placed in a reagent bottle according to a molar ratio of 2.5:1. DMF and DMSO are taken according to a volume ratio of 4:1 and poured into the reagent bottle to configure a one-dimensional perovskite precursor solution with a solution concentration of 80 mg / ml. The one-dimensional perovskite quantum dots are added to the one-dimensional perovskite precursor solution to make the concentration of the one-dimensional perovskite quantum dots in the one-dimensional perovskite precursor solution be 10 mg / ml and the particle size be 3-10 nm. The solution is heated and stirred at a temperature atmosphere of 60 ℃ until it is dissolved. The one-dimensional perovskite precursor solution is filtered. The filtered one-dimensional perovskite precursor solution is 75 μL, which is coated on the ITO substrate. The area of the ITO substrate is 2.25 cm 2 . The spin coating parameters are set as two-step spin coating. The first step is set as 1700-1800 rpm spin coating for 9 s with an acceleration of 650 rpm / s 2 . The second step is set as 5300-5500 rpm spin coating for 33 s with an acceleration of 1500 rpm / s 2 . After setting, start spin coating. Then take 900 μL chlorobenzene as anti-solvent with a pipette, and pour all the chlorobenzene on the substrate from the middle of the substrate at a high speed spin coating to 28 s.

[0125] Immediately after spin coating, place the substrate on the hot stage, and anneal at a temperature atmosphere of 150 ℃ for 15 min to obtain a one-dimensional perovskite film.

[0126] Example 3

[0127] Preparation method of quantum dot optimized one-dimensional perovskite thin film:

[0128] The ITO-coated glass substrate was sequentially cleaned with dishwashing liquid, deionized water, and anhydrous ethanol, and then sequentially ultrasonically cleaned with anhydrous ethanol, deionized water, acetone, and anhydrous ethanol for 15 min. After the ultrasonic cleaning was completed, the substrate was placed in a 60°C oven until it was dried. The dried ITO substrate was subjected to plasma surface treatment for 90 s. The ITO substrate had an area of 2.25 cm 2 A 100 μL solution of perovskite quantum dots having a concentration of 20 mg / ml and a particle size of 3-10 nm was spin-coated on the ITO substrate at a speed of 3500-3800 rpm for 40 s, with an acceleration of 2000 rpm / s. 2 The substrate was annealed at a temperature of 190°C for 5 min.

[0129] Pyrrolidine (C4NH9) and PbI2 were placed in a reagent bottle in a molar ratio of 0.5:1, and DMF and DMSO were poured into the reagent bottle in a volume ratio of 5:1 to configure a one-dimensional perovskite precursor solution having a solution concentration of 100 mg / ml. The solution was heated and stirred at a temperature of 60°C until it was dissolved, and the perovskite precursor solution was filtered. 100 μL of the filtered perovskite precursor solution was used to coat the ITO substrate, and spin coating parameters were set on a spin coater as follows: for the first step, a speed of 1500-1600 rpm was set for 10 s, with an acceleration of 500 rpm / s 2 , and for the second step, a speed of 5300-5500 rpm was set for 35 s, with an acceleration of 1000 rpm / s 2 After the parameters were set, spin coating was started, and 800 μL of chlorobenzene was used as an anti-solvent. The chlorobenzene was injected onto the substrate from the middle of the substrate at a high speed and at a speed of 25 s.

[0130] The substrate was immediately placed on a hot stage after the spin coating was completed, and was annealed at a temperature of 180°C for 15 min to obtain a one-dimensional perovskite film.

[0131] Example 4:

[0132] A method for preparing a one-dimensional perovskite film having an optimized buried interface was as follows:

[0133] The ITO-coated glass substrate was sequentially cleaned with dishwashing liquid, deionized water, and anhydrous ethanol, and then sequentially ultrasonically cleaned with anhydrous ethanol, deionized water, acetone, and anhydrous ethanol for 15 min. After the ultrasonic cleaning was completed, the substrate was placed in a 60°C oven until it was dried. The dried ITO substrate was subjected to plasma surface treatment for 90 s. The ITO substrate had an area of 2.25 cm 2 A 75 μL solution of perovskite quantum dots having a concentration of 10 mg / ml and a particle size of 3-10 nm was spin-coated on the ITO substrate at a speed of 4800-5000 rpm for 25 s, with an acceleration of 3000 rpm / s.2 The temperature atmosphere is 85°C, and annealing time is 5 min.

[0134] Pyrrolidine (C4NH9) and PbI2 are placed in a reagent bottle in a molar ratio of 5:1, DMF and DMSO are poured into the reagent bottle in a volume ratio of 1:5 to configure a one-dimensional perovskite precursor solution with a solution concentration of 50 mg / ml, and the solution is heated and stirred to dissolve at a temperature atmosphere of 40°C. The perovskite precursor solution is filtered, and 50 μL of the filtered perovskite precursor solution is used to coat an ITO substrate. The spin coating parameters are set on a spin coater as follows: 1900-2000 rpm for 9 s at an acceleration of 800 rpm / s for the first step, and 5800-6000 rpm for 30 s at an acceleration of 2000 rpm / s for the second step. 2 2 After the parameters are set, spin coating is started, and 1000 μL of chlorobenzene is used as an anti-solvent. The chlorobenzene is injected onto the substrate from the middle of the substrate at a high speed to form a film on the substrate.

[0135] After spin coating, the substrate is immediately placed on a hot stage, and annealing is performed at a temperature atmosphere of less than 85°C for 15 min to obtain a one-dimensional perovskite film.

[0136] Example 5

[0137] The difference from Example 1 is that the particle size is 1-2 nm.

[0138] Example 6

[0139] The difference from Example 1 is that the particle size is 15-20 nm.

[0140] Example 7

[0141] The difference from Example 1 is that the two-step spin coating is adjusted to one-step spin coating, and the substrate is rotated at a speed of 3500-3800 rpm for 35 s at an acceleration of 2000 rpm / s. 2

[0142] Example 8

[0143] The difference from Example 1 is that the second step parameter in the two-step spin coating is set to 3500-3800 rpm for 33 s at an acceleration of 1500 rpm / s. 2

[0144] Example 9

[0145] The difference from Example 1 is that C5NH 11 is used instead of C4NH9.

[0146] Example 10

[0147] ​​​The difference from Example 1 is that C4NH 13 is replaced by C6NH9.

[0148] Comparative Example 1

[0149] Preparation method of perovskite quantum dot film:

[0150] The glass substrate plated with indium tin oxide (ITO) is sequentially cleaned with detergent, deionized water, and anhydrous ethanol, and then sequentially ultrasonically cleaned with anhydrous ethanol, deionized water, acetone, and anhydrous ethanol for 15 min. After the ultrasonic cleaning is completed, the glass substrate is placed in a 60°C oven until it is dried. The ITO substrate after drying is subjected to plasma surface treatment for 90 s. The ITO substrate has an area of 2.25 cm 2 . 75 μL of perovskite quantum dot solution with a concentration of 20 mg / ml and a particle size of 3-10 nm is spin-coated on the ITO substrate, and the rotation speed of the ITO substrate, i.e., the substrate, is 4000-4300 rpm for 35 s, with an acceleration of 2000 rpm / s. 2 . Annealing is performed at a temperature of 150°C for 10 min to obtain a perovskite quantum dot film.

[0151] Comparative Example 2

[0152] Preparation method of one-dimensional perovskite film without perovskite quantum dots:

[0153] The glass substrate plated with indium tin oxide (ITO) is sequentially cleaned with detergent, deionized water, and anhydrous ethanol, and then sequentially ultrasonically cleaned with anhydrous ethanol, deionized water, acetone, and anhydrous ethanol for 15 min. After the ultrasonic cleaning is completed, the glass substrate is placed in a 60°C oven until it is dried. The ITO substrate after drying is subjected to plasma surface treatment for 90 s. Then, a one-dimensional perovskite film is prepared by a one-step method.

[0154] C4NH9 and PbBr2 are placed in a reagent bottle in a molar ratio of 2.5:1, and DMF and DMSO are taken in a volume ratio of 4:1 to configure a one-dimensional perovskite precursor solution with a solution concentration of 80 mg / ml. The solution is heated and stirred at a temperature of 60°C to dissolve, and the perovskite precursor solution is filtered. 75 μL of the filtered perovskite precursor solution is used to coat the ITO substrate, and the ITO substrate has an area of 2.25 cm 2 . The spin-coating parameters are set on the spin coater as two-step spin coating. The first step is set to 1700-1800 rpm for 9 s, with an acceleration of 650 rpm / s. 2 . The second step is set to 5300-5500 rpm for 33 s, with an acceleration of 1500 rpm / s. 2 . After the settings are completed, spin coating is started. Then, 900 μL of chlorobenzene is taken as an anti-solvent, and the chlorobenzene is completely flushed onto the substrate from the middle of the substrate at a high speed spin coating time of 28 s.

[0155] After the spin coating, the substrate was immediately placed on a hot plate and annealed at a temperature of 150°C for 15 minutes to obtain a one-dimensional perovskite film. The test results of the film are shown in Figure 4 and Figure 5 .

[0156] Comparative Example 3:

[0157] The difference between Comparative Example 2 and Comparative Example 3 is that C4NH9 is replaced by C5NH9. 11

[0158] Comparative Example 4:

[0159] The difference between Comparative Example 2 and Comparative Example 4 is that C4NH9 is replaced by C6NH9. 13

[0160] Table 1. Nakedness and void size range of the films of the comparative examples and the examples

[0161]

[0162]

[0163] Table 2. Range of the wavelength and the degree of absorption enhancement of the comparative examples and the examples

[0164]

[0165]

[0166] The coverage of the pure perovskite quantum dot film and the pure one-dimensional perovskite film is poor. The concentration of the AX salt in the one-dimensional perovskite precursor and the size of the perovskite quantum dot solution have a great influence on the morphology and absorption performance of the perovskite quantum dot / one-dimensional perovskite film finally formed.

[0167] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.​​

Claims

1. A method for preparing a one-dimensional perovskite thin film, characterized by, The film forming includes one-dimensional perovskite precursor in solution crystallizing and film forming with perovskite quantum dots as initial crystallization sites; The perovskite quantum dots have a particle size of 3-10 nm; The film forming is to spin-coat one-dimensional perovskite precursor solution containing perovskite quantum dots on a substrate, and then perform anti-solvent crystallization and annealing to obtain a one-dimensional perovskite film. The one-dimensional perovskite precursor solution is obtained by mixing A + , B 2+ , X - species and a solvent; A is a heterocyclic compound, the heteroatom in the heterocyclic compound is nitrogen; B is a metal; X is halogen; The heterocyclic compound is a five-membered heterocyclic ring, a six-membered heterocyclic ring, or a seven-membered heterocyclic ring;B 2+ is Pb 2+ ; or Sn 2+ ; X - is I - , Br - , or Cl - ; The one-dimensional perovskite film satisfies TF>1.0, wherein the calculation method of TF is shown in formula 1: TF = 0.5 Formula 1 In formula 1, r A is the ionic radius of the A-site, r B is the ionic radius of the B-site metal ion, r X is the ionic radius of the X-site.

2. The method of claim 1, wherein the one-dimensional perovskite thin film is prepared by a process comprising: The amount of one-dimensional perovskite precursor solution on the perovskite quantum dot layer is 22-45 μL / cm 2 .

3. The method of claim 1, wherein the one-dimensional perovskite thin film is prepared by a process comprising: The spin-coating includes low-speed spin-coating and high-speed spin-coating. In the low-speed spin coating, the rotation speed of the substrate is 1500-2000 rpm, and the acceleration is 500-800 rpm / s 2 , and the spin coating time is 8-10 s; in the high-speed spin coating, the rotation speed of the substrate is 5000-6000 rpm, and the acceleration is 1000-2000 rpm / s 2 , and the spin coating time is 30-35 s.

4. The method of claim 1, wherein the one-dimensional perovskite thin film is prepared by a process comprising: The perovskite quantum dot layer is obtained by pre-spin-coating perovskite quantum dot solution on a substrate by spin-coating, and then performing annealing.

5. The method of claim 4, wherein the one-dimensional perovskite thin film is prepared by a process comprising: The amount of perovskite quantum dot solution used in the pre-spin coating step on the substrate is 22-45 μL / cm 2 .

6. The method of claim 4, wherein the one-dimensional perovskite thin film is prepared by a process comprising: The concentration of the perovskite quantum dot solution in the pre-spin-coating step is 1-20 mg / ml.

7. The method for preparing a one-dimensional perovskite thin film according to claim 4, characterized in that, The rotation speed of the substrate in the pre-spinning step is 3500-5000 rpm, and the acceleration is 2000-3000 rpm / s 2 The spin time is 25-40 s.

8. The method for preparing a one-dimensional perovskite thin film according to claim 1, characterized in that, The concentration of the perovskite quantum dots in the one-dimensional perovskite precursor solution containing perovskite quantum dots is 1-10 mg / ml.

9. The method for preparing a one-dimensional perovskite thin film according to claim 3, characterized in that, The anti-solvent crystallization is to rapidly add an anti-solvent to the substrate when the high-speed spin-coating is performed for 25-30 s; The anti-solvent is any one of chlorobenzene, diethyl ether and acetone; The amount of the anti-solvent is 360-450 μL / cm 2 .

10. The method for preparing a one-dimensional perovskite thin film according to claim 1, characterized in that, The annealing is to place the coated substrate at a temperature of 80-200 ℃ for 10-20 min.

11. The method for preparing a one-dimensional perovskite thin film according to claim 1, characterized in that, The solvent is at least one of DMF and DMSO.

12. The method for preparing a one-dimensional perovskite thin film according to claim 1, characterized in that, The one-dimensional perovskite precursor solution includes AX and BX2.

13. The method of claim 12, wherein the one-dimensional perovskite thin film is prepared by a process comprising: The molar ratio of AX and BX2 is 0.5-5:1; and the total concentration of A, B and X elements in the one-dimensional perovskite precursor solution is 50-100 mg / ml.

14. The method for preparing a one-dimensional perovskite thin film according to claim 1, characterized in that, A + , B 2+ , X - and solvent are mixed and heated to 50-100°C to stir, dissolve, to obtain a one-dimensional perovskite precursor solution.

15. The method for preparing a one-dimensional perovskite thin film according to claim 4, characterized in that, The substrate is cleaned before spin-coating or pre-spin-coating on the substrate.

16. The method of claim 15, wherein the one-dimensional perovskite thin film is prepared by a method comprising: The substrate is ITO conductive glass, FTO conductive glass or AZO conductive glass.

17. The method of claim 15, wherein the one-dimensional perovskite thin film is prepared by a process comprising: The cleaning method specifically includes: sequentially cleaning the substrate with dishwashing liquid, deionized water and anhydrous ethanol, and then ultrasonic cleaning in a cleaning solution for more than 15 min; and after the ultrasonic cleaning, placing the substrate in an oven in a temperature atmosphere lower than 200 ℃ for drying.

18. The method of claim 17, wherein the one-dimensional perovskite thin film is prepared by a method comprising: The cleaning solution is at least one of anhydrous ethanol, deionized water, acetone and anhydrous ethanol.

19. The method of claim 15, wherein the one-dimensional perovskite thin film is prepared by a method comprising: The dried substrate is subjected to plasma surface treatment for 5-150 s.

20. The method of claim 15, wherein the one-dimensional perovskite thin film is prepared by a method comprising: The dried substrate is placed in an ultraviolet-ozone environment for 1-30 min.

21. A one-dimensional perovskite thin film, characterized in that, The one-dimensional perovskite film is prepared according to the method of any one of claims 1-20.

22. Application of the one-dimensional perovskite film of claim 21 in an optoelectronic device.

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