Search

CN-115768220-B - Method for regulating orientation of polycrystalline film by using antisolvent

CN115768220BCN 115768220 BCN115768220 BCN 115768220BCN-115768220-B

Abstract

The invention relates to the technical field of nano material preparation and polycrystalline film preparation, in particular to a method for regulating and controlling orientation of a polycrystalline film by using an antisolvent, which aims to solve the problems that the existing preparation method is complex in implementation mode, the preparation process is difficult to be compatible with industrial production and the integrity of the polycrystalline film is possibly negatively influenced. The method for regulating the orientation of the polycrystalline thin film by using the antisolvent comprises the steps of coating a pre-prepared precursor solution on a substrate, coating the antisolvent corresponding to a target specific orientation on the substrate where the precursor solution is located, and carrying out low-temperature annealing on the coated substrate with the precursor solution and the antisolvent to obtain the polycrystalline thin film with the target specific orientation, wherein the annealing duration of the low-temperature annealing is inversely related to annealing temperature. The polycrystalline thin film prepared by the preparation method provided by the invention has the advantages of high orientation consistency, low defect density, high carrier mobility and more compact and flat thin film morphology.

Inventors

  • WEI JING
  • LI HONGBO
  • SUN XIANGYU
  • LI DONGNI
  • ZHAO LU

Assignees

  • 北京理工大学

Dates

Publication Date
20260505
Application Date
20221212

Claims (9)

  1. 1. A method for controlling orientation of a polycrystalline thin film using an antisolvent, the method comprising: s1, coating a prepared perovskite precursor liquid on a substrate; S2, coating an anti-solvent corresponding to a target specific orientation on the substrate where the perovskite precursor liquid is located, wherein when the target specific orientation is 111 orientation, the anti-solvent is a pure isopropanol solvent, and when the target specific orientation is 001 orientation, the anti-solvent is a mixed solution of formamidine iodine, methylamine iodine and methylamine chlorine serving as solutes and isopropanol serving as a solvent; S3, carrying out low-temperature annealing on the substrate with the perovskite precursor liquid and the antisolvent after coating to obtain the polycrystalline film with the target specific orientation, wherein the annealing time length of the low-temperature annealing is inversely related to the annealing temperature; The perovskite precursor liquid comprises the components (FA 0.85 MA 0.10 Cs 0.05 )Pb(I 2.85 Br 0.15 ) with the concentration of 1.2mol/mL.
  2. 2. The method of claim 1, wherein the step of applying the pre-prepared perovskite precursor solution to the substrate further comprises applying the pre-prepared perovskite precursor solution to the substrate by spin coating at 2000rpm for 5s and 4000rpm for 20 s; the step of applying an anti-solvent corresponding to the target specific orientation to the substrate on which the perovskite precursor liquid is located further comprises applying an anti-solvent corresponding to the target specific orientation to the substrate before the last 10s of spin-coating the perovskite precursor liquid at 4000 rpm.
  3. 3. The method according to claim 1, wherein the mixed solution of formamidine iodine, methyl amine iodine and methyl amine chlorine as solutes and isopropanol as solvent is prepared by adding formamidine iodine, methyl amine iodine and methyl amine chlorine in a ratio of 10:1:1 to pure isopropanol solvent and mixing.
  4. 4. A method according to claim 3, wherein the concentration of formamidine iodine in the mixed solvent of isopropyl alcohol, formamidine iodine, methylamine iodine and methylamine chloride is 5mg/mL, and the concentration of methylamine iodine and methylamine chloride is 0.5mg/mL.
  5. 5. The method according to claim 1, wherein each 1mL of the perovskite precursor liquid is prepared by dissolving 175.44mg of formamidine iodine, 553.2mg of lead iodide, 12.77mg of cesium bromide and 13.44mg of methylamine bromide in a mixed solution of 800uLDMF+200uLDMSO and stirring uniformly.
  6. 6. The method of any one of claims 1 to 5, wherein the annealing temperature is 100 to 150 ℃ and the annealing time period is 6 to 25 minutes.
  7. 7. The method of claim 6, wherein the annealing temperature is 150 ℃ and the annealing time period is 6 minutes.
  8. 8. The method of claim 6, wherein the annealing temperature is 130 ℃ and the annealing time period is 15 minutes.
  9. 9. The method of claim 6, wherein the annealing temperature is 100 ℃ and the annealing time period is 25 minutes.

Description

Method for regulating orientation of polycrystalline film by using antisolvent Technical Field The invention relates to the technical field of nano material preparation and polycrystalline film preparation, in particular to a method for regulating and controlling orientation of a polycrystalline film by using an antisolvent. Background Polycrystalline thin films with specific orientations are important in the photovoltaic and photovoltaic fields. Among them, the polycrystalline thin film with specific orientation has the following advantages in the application of photoelectric and photovoltaic devices: 1. the polycrystalline thin films with the same orientation have lower defect density and higher carrier mobility due to less lattice mismatch at the interface, so that the photogenerated carrier transfer efficiency is improved, and the device performance is improved; 2. The efficiency loss of the film in a continuous working state is reduced, and potential defect sites which exist at the interface and can be activated by the photo-aging process due to lattice mismatch are reduced. Particularly, in the organic photoelectric/photovoltaic device and the perovskite photoelectric/photovoltaic device, the device prepared based on the polycrystalline film with the same orientation can effectively solve the problems of phase separation and defect density rise caused by the photo-aging process, thereby greatly improving the stability of the device under the continuous working condition and providing effective technical support for industrialization of the photoelectric device based on the organic or perovskite photoactive layer; 3. the polycrystalline thin films with the same orientation can also reduce gaps among crystals, further inhibit the erosion process of water oxygen and the like on the photosensitive layer through gaps at grain boundaries, and prolong the service life of the device. At present, the method for obtaining the polycrystalline film with consistent orientation mainly comprises the steps of controlling thermal gradient, adjusting intermediate, adjusting phase components, applying external force and the like, but the method has the problems of complicated implementation mode, difficult compatibility of the preparation process with industrial production, possibility of negatively affecting the integrity of the polycrystalline film and the like. Taking control of thermal gradients and application of external forces to regulate crystal orientation as an example. The preparation process of the polycrystalline film with consistent orientation by thermal gradient comprises the steps of coating MAFa (the preparation process needs to be stirred at the low temperature of minus 16 ℃ for two hours) which is prepared in advance on the surface of a substrate in a doctor blade mode after being dissolved with methyl iodide and lead iodide in a mass ratio of 25%, and then heating and crystallizing by applying a heat source with the temperature of 85 ℃ on one side of the substrate to obtain the polycrystalline film with relatively consistent orientation, wherein the heating process usually needs to last for more than 2 hours, the film obtained by the preparation method is sensitive to the preparation environment, meanwhile, the problem of smaller crystallization scale exists, and the time and energy loss are large. The preparation process of regulating crystal orientation by applying external force is that the prepared polycrystalline film is physically pressurized by using organic film material with specific structure, and the secondary crystallization of crystal is carried out by utilizing the characteristic of strong perovskite structure plasticity, so as to achieve the purpose of crystal regrowth into a consistent orientation structure. Accordingly, there is a need in the art for a new method of preparing polycrystalline thin films that addresses the above-described problems. Disclosure of Invention The invention aims to solve the technical problems that the existing preparation method is complex in implementation mode, difficult to be compatible with industrial production in the preparation process and can negatively influence the integrity of the polycrystalline thin film. The invention provides a method for regulating and controlling orientation of a polycrystalline film by using an antisolvent, which comprises the following steps: S1, coating a precursor solution prepared in advance on a substrate; S2, coating an antisolvent corresponding to the target specific orientation on the substrate where the precursor liquid is located; And S3, carrying out low-temperature annealing on the coated substrate with the precursor liquid and the antisolvent to obtain the polycrystalline film with the target specific orientation, wherein the annealing duration of the low-temperature annealing is inversely related to the annealing temperature. In a preferred technical scheme of the above method, the step S1 specifically incl