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US-20260125313-A1 - Method of Preparing a Perovskite Film

US20260125313A1US 20260125313 A1US20260125313 A1US 20260125313A1US-20260125313-A1

Abstract

The present disclosure broadly relates to a method of depositing a perovskite film on a substrate, the perovskite having a formula ABX 3 . The method may comprise the step of co-evaporating a compound of formula AX and a compound of formula BX 2 onto the substrate, wherein: A is selected from one or more monovalent metal cations or organic cations; B is selected from one or more metal cations or metalloid cations; and X is selected from one or more halide anions or pseudohalide anions. There is also disclosed herein a perovskite film produced by the method as well as a photovoltaic cell comprising the perovskite film.

Inventors

  • Annalisa Bruno
  • Herlina Arianita DEWI
  • Subodh Gautam Mhaisalkar
  • Erdenebileg ENKHTUR

Assignees

  • NANYANG TECHNOLOGICAL UNIVERSITY

Dates

Publication Date
20260507
Application Date
20251105
Priority Date
20241105

Claims (20)

  1. 1 . A method of depositing a perovskite film on a substrate, the perovskite having a formula ABX 3 , the method comprising the step of co-evaporating a compound of formula AX and a compound of formula BX 2 onto the substrate, wherein: A is selected from one or more monovalent metal cations or organic cations; B is selected from one or more metal cations or metalloid cations; and X is selected from one or more halide anions or pseudohalide anions.
  2. 2 . The method of claim 1 , wherein: A is selected from Cs + , Rb + , K + , CH 3 NH 3 − , [HC(NH 2 ) 2 ] + , ethylammonium, guanidinium, or a combination thereof; B is selected from Pb 2+ , Sn 2+ , Ge 2+ , Be 2+ , Mn 2+ , Cu 2+ , Sb 2+ , or a combination thereof, and X is selected from Cl − , Br − , I − , SCN − , CN − , or a combination thereof.
  3. 3 . The method of claim 1 , wherein the co-evaporating step is undertaken for a time duration of less than about 90 minutes.
  4. 4 . The method of claim 1 , wherein the co-evaporating step comprises the step (a1) of heating the compound of formula AX to a temperature of between about 60° C. to about 700° C.
  5. 5 . The method of claim 1 , wherein the co-evaporating step comprises the step (a1) of heating the compound of formula AX to a temperature of between about 130° C. to about 180° C.
  6. 6 . The method of claim 1 , wherein the co-evaporating step comprises the step (a2) of heating the compound of formula BX 2 to a temperature of between about 200° C. to about 600° C.
  7. 7 . The method of claim 1 , wherein the co-evaporating step comprises the step (a2) of heating the compound of formula BX 2 to a temperature of between about 350° C. to about 425° C.
  8. 8 . The method of claim 1 , wherein the method is conducted in a vacuum chamber.
  9. 9 . The method of claim 8 , wherein the vacuum chamber is operated at a pressure maintained between about 1×10 −5 Pa to about 1×10 −2 Pa.
  10. 10 . The method of claim 1 , wherein the mole ratio of the compound of formula AX to the compound of formula BX 2 is between about 8:1 to about 1:2.
  11. 11 . The method of claim 1 , wherein the perovskite film is deposited on the substrate at a deposition rate of greater than about 5 nm/minute.
  12. 12 . The method of claim 1 , wherein the compound of formula AX and the compound of formula BX 2 are placed on separate sources.
  13. 13 . The method of claim 12 , comprising the step of varying the distance from each source to the substrate.
  14. 14 . The method of claim 1 , wherein the substrate is coated glass.
  15. 15 . The method of claim 1 , wherein the method does not comprise post-annealing the deposited perovskite film to the substrate.
  16. 16 . A perovskite film produced by the method of claim 1 .
  17. 17 . The perovskite film of claim 16 , wherein the perovskite has a grain size of between about 20 nm to about 300 nm.
  18. 18 . The perovskite film of claim 16 , having a thickness of between about 100 nm to about 1200 nm.
  19. 19 . A photovoltaic cell comprising the perovskite film of claim 16 .
  20. 20 . The photovoltaic cell of claim 19 , having a power conversion efficiency (PCE) of over about 5%.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of Singapore Application No. 10202403420X filed with the Intellectual Property Office of Singapore on Nov. 5, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present invention generally relates to a method of preparing a perovskite film. The present invention also relates to a perovskite film prepared by the method and use of the perovskite film in a photovoltaic cell. BACKGROUND ART Perovskite solar cells (PSCs) have emerged as attractive alternative solar cell materials, thanks to their exceptional power conversion efficiencies, low-cost fabrication processes, and versatility in design. Different perovskite fabrication routes have been established, which are broadly categorized into solution-processable deposition or vacuum deposition. Solution-processable deposition has been the most commonly used deposition route and may be considered the most efficient perovskite fabrication method, with PSCs produced by this method having the highest power conversion efficiencies (PCE) in the range of 26%. Despite the high PCE, toxic solvents and limited scalability are major considerations for adapting the technique to large-scale industrial production. In contrast, vacuum deposition has generally been used industrially, particularly in light-emitting display devices. As such, there are prospects for integrating perovskite deposition processes with vacuum deposition processes. However, the slow co-evaporation involved with vacuum deposition is a major obstacle to commercialization, with the fastest recorded deposition times at about 50 minutes, ranging to hours for multiple vacuum deposition steps. Moreover, a common step required in perovskite fabrication is post-annealing, which may substantially add to the manufacturing time and increase power consumption. There is thus a need for a method of producing a perovskite film using vacuum deposition that, for example, are more time-efficient, where the produced perovskite films have good PCE results, and/or where the method does not require post-annealing. Accordingly, there is a need for a method of producing a perovskite film using a vacuum deposition process that overcomes, or at least ameliorates, one or more of the disadvantages mentioned above. SUMMARY According to a first aspect, there is provided a method of depositing a perovskite film on a substrate, the perovskite having a formula ABX3, the method comprising the step of co-evaporating a compound of formula AX and a compound of formula BX2 onto the substrate, wherein: A is selected from one or more monovalent metal cations or organic cations;B is selected from one or more metal cations or metalloid cations; andX is selected from one or more halide anions or pseudohalide anions. Advantageously, the method as described herein may provide a relatively fast means of producing a perovskite film, which may reduce the fabrication time. Advantageously, the vacuum deposition method may substantially avoid the use of solvents, reducing costs and environmental impact. According to a second aspect, there is provided a perovskite film produced by the method as described herein. Advantageously, the perovskite film as described herein may not need to be post-annealed to the substrate after being produced. According to a third aspect, there is provided a photovoltaic cell comprising the perovskite film as described herein. Advantageously, the photovoltaic cell comprising the perovskite film as described herein may provide good power conversion efficiency (PCE) characteristics. BRIEF DESCRIPTION OF DRAWINGS The accompanying drawings illustrate a disclosed embodiment and serve to explain the principles of the disclosed invention. It is to be understood, however, that the drawings are designed for purposes of illustration only, and not as a definition of the limits of the invention. FIG. 1 is a schematic showing the setup for a method of depositing a perovskite film on a substrate according to one embodiment. FIG. 2 is a graph showing deposition rates of different deposition times from 150 to 25 minutes. FIG. 3 is a schematic showing a device configuration which incorporates the co-deposited MAPbI3 perovskite film. FIG. 4 is a graph showing the power conversion efficiency (PCE) of a co-evaporated MAPbI3 perovskite film using different deposition times from 150 to 25 minutes. FIG. 5 is a graph showing the photovoltaic parameters: open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF) of different deposition times from 150 to 25 minutes. FIG. 6 is a composite graph showing photovoltaic parameters: PCE, Voc, Jsc, and FF of co-evaporated perovskite solar cells incorporating MAPbI3 film as-deposited (without annealing) and MAPbI3 film after post-annealing at 100° C. for 30 minutes. FIG. 7A is a graph showing a Tauc plot of co-evaporated MAPbI3 perovskite films produced using a