# US 2024/0196718 A1 · Surface treatments for perovskite films to improve efficiency/stability of resulting solar cells

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- Number: US 2024/0196718 A1
- Document ID: US20240196718A1
- Status: Published application
- Kind: A1
- Application number: 18/245,387
- Filed: 2021-09-16
- Published: 2024-06-13
- Earliest claimed: 2020-09-16
- Assignees: The University of North Carolina at Chapel Hill
- Applicants: The University of North Carolina at Chapel Hill
- Inventors: Yuze Lin; Ye Liu; Shangshang Chen; Jinsong Huang
- Web page: https://patentgrep.com/patent/US20240196718A1

## CPC

- H10K 71/20: Changing the shape of the active layer in the devices, e.g. patterning
- B08B 7/0028: {by adhesive surfaces}
- C07F 7/24: Lead compounds
- C07F 19/00: Metal compounds according to more than one of main groups C07F1/00 - C07F17/00
- H10K 30/50: Photovoltaic [PV] devices
- H10K 85/50: Organic perovskites; Hybrid organic-inorganic perovskites [HOIP], e.g. CH3NH3PbI3
- H10K 30/57: comprising multiple junctions, e.g. tandem PV cells
- Y02E 10/549: Organic PV cells
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Described herein are surface treatment methods for removing one or more surface defect layers from polycrystalline films, polycrystalline films that are free of one or more defect surface layers, and use of the films in solar cells. In certain embodiments, the method is conducted by means of an adhesive tape or mechanical polishing. As described herein, solar cells containing the surface treated perovskite films show enhanced efficiency and stability.

## Claims

### Claim 1

A polycrystalline perovskite film comprising a perovskite composition of formula ABX3 or A2BX4, wherein,
A is selected from the group consisting of methylammonium (MA), tetramethylammonium, formamidinium (FA), cesium, rubidium, potassium, sodium, butylammonium, phenethylammonium, phenylammonium, guanidinium, ammonium, and a combination thereof;
B is a metal cation selected from the group consisting of lead, tin, calcium, cadmium, germanium, zinc, nickel, platinum, palladium, mercury, titanium, silicon, and a combination thereof; and
X is selected from the group consisting of Cl−, Br−, F−, I−, SCN−, and a combination thereof;
wherein said polycrystalline perovskite film is free of one or more surface defect layers.

### Claim 2 (depends on 1)

The polycrystalline perovskite film of claim 1, further comprising a residue of adhesive on one or more surfaces of said film, wherein said residue has a thickness of about 1 nm to about 1000 nm.

### Claim 3 (depends on 1)

The polycrystalline perovskite film of claim 1, wherein said perovskite composition is of formula ABX3, wherein A is selected from the group consisting of Cs, FA, MA, Rb, and a combination thereof; B is selected from the group consisting of lead, tin, and a combination thereof; and X is selected from the group consisting of I−, Br−, and a combination thereof, wherein:
said perovskite composition is selected from the group consisting of FAPbBr3, FAPbI3, FAPbCl3, MAPbBr3, MAPbI3, MAPbC3, CsPbBr3, CsPbI3, and CsPbC3; or
said perovskite composition is selected from the group consisting of CsyFA1-x-y MAxPbI3-zBrz (y≤x, x+y<1, z≤3), RbxCsyFA1-x-y-fMAfPbI3-zBrz (y≤x≤f, x+y+f<1, z≤3), CsxFA1-xPb1-zSnzI3 (x<1, z≤1), and CsxFA1-xPbI3-zBrz (z<1, z≤3); or
said perovskite composition is selected from the group consisting of Cs0.4FA0.6Pb(I0.64Br0.36)3, Cs0.05FA0.81MA0.14PbI2.55Br0.45, Rb0.05Cs0.05FA0.85MA0.05PbI2.85Br0.15, and Cs0.20FA0.80Pb0.50Sn0.50I3.

### Claim at position 4

4-7. (canceled)

### Claim 8 (depends on 1)

The polycrystalline perovskite film of claim 1, wherein;
said film has a thickness of about 1 nm to about 10 μm; optionally, wherein said film has a thickness of about 100 nm to 2000 nm; and
said film is smooth, having a root mean square roughness of about 8 nm to about 10 nm.

### Claim at position 6

9-11. (canceled)

### Claim 12 (depends on 1)

A semiconductor device comprising:
one or more anode layers;
one or more cathode layers; and
one or more active layers, wherein at least one of said one or more active layers comprises the polycrystalline perovskite film of claim 1,
wherein said device is selected from the group consisting of solar cell, light emitting diode, photodiode, photoelectrochemical cell, photoresistor, phototransistor, photomultiplier, photoelectric cell, electrochromic cell, and radiation detector.

### Claim 13

(canceled)

### Claim 14 (depends on 12)

The semiconductor device of claim 12, wherein said solar cell is a single junction solar cell or a tandem solar cell.

### Claim 15

(canceled)

### Claim 16 (depends on 1)

A solar cell, comprising:
(a) two or more transparent conductive oxide layers;
one or more hole transport layers;
one or more electron transport layers; and
one or more active layers, wherein at least one of said one or more active layers comprises the polycrystalline perovskite film of claim 1; or
(b) one or more transparent conductive oxide layers;
one or more conductive electrode layers;
one or more hole transport layers;
one or more electron transport layers; and
one or more active layers, wherein at least one of said one or more active layers comprises the polycrystalline perovskite film of claim 1.

### Claim 17

(canceled)

### Claim 18 (depends on 1, 16)

The solar cell of claim 16, wherein said solar cell comprises:
one transparent conductive oxide layer;
one conductive electrode layer;
one hole transport layer;
one electron transport layer; and
one active layer, wherein said active layer comprises the polycrystalline perovskite film of claim 1.

### Claim 19 (depends on 18)

The solar cell of claim 18, wherein:
(a) said hole transport layer is disposed directly on said transparent conductive oxide layer;
said active layer comprising said polycrystalline perovskite film is disposed directly on said hole transport layer;
said electron transport layer is disposed directly on said active layer; and
said conductive electrode layer is disposed on said electron transport layer; or
(b) said electron transport layer is disposed directly on said transparent conductive oxide layer;
said active layer comprising said polycrystalline perovskite film is disposed directly on said electron transport layer;
said hole transport layer is disposed directly on said active layer; and
said conductive electrode layer is disposed directly on said hole transport layer.

### Claim 20

(canceled)

### Claim 21 (depends on 16)

The solar cell of claim 16, wherein:
said one or more hole transport layers are selected from the group consisting of PTAA, Spiro-OMeTAD, PEDOT:PSS, NiO, MoO3, V2O5, Poly-TPD, EH44, P3HT, and a combination thereof;
said one or more electron transport layers are selected from the group consisting of C60, BCP, TiO2, SnO2, PCBM, ICBA, ZnO, ZrAcac, LiF, TPBI, PFN, Nb2O5, and a combination thereof;
said one or more or two or more transparent conductive oxide layers are selected from the group consisting of ITO, FTO, ZITO, and AZO; and
said one or more conductive electrode layers are selected from the group consisting of Al, Au, Cu, Cr, Ca, Mg, Ag, and Ti.

### Claim at position 17

22-24. (canceled)

### Claim 25 (depends on 16)

The solar cell of claim 16, wherein:
said transparent conductive oxide layer is ITO;
said hole transport layer is PTAA;
said electron transport layer is C60 or PCBM; and
said conductive electrode layer is Cu; and
optionally, further comprising a buffer layer of BCP disposed between said electron transport layer and said conductive electrode layer.

### Claim at position 19

26-27. (canceled)

### Claim 28 (depends on 17)

The solar cell of claim 17, wherein:
said solar cell has a Power Conversion Efficiency of about 22%; and
said solar cell retains about 97.1% of said Power Conversion Efficiency after continuous illumination for 1440 hours.

### Claim 29 (depends on 1)

A surface treatment method for removing one or more surface defect layers from the polycrystalline perovskite film of claim 1, comprising:
a) contacting an adhesive with one or more surfaces of a polycrystalline perovskite film; and
b) removing a portion of said adhesive from said polycrystalline perovskite film surfaces,
wherein a and b are carried out one or more times to remove said one or more surface defect layers;
wherein said method is a scalable roll-to-roll process;
wherein said method produces a polycrystalline perovskite film having a residue of adhesive on said one or more surfaces of said film, wherein said residue of adhesive has a thickness of about 1 nm to about 1000 nm; and
wherein said polycrystalline perovskite film has a thickness of about 1 nm to about 10 μm.

### Claim at position 22

30-35. (canceled)

### Claim 36 (depends on 29)

The surface treatment method of claim 29, wherein:
said adhesive is selected from the group consisting of resin, rubber, polyterpene, polyisoprene, polyvinyl alcohol (PVA), polyacrylic acid (PAA), cyanoacrylate, polyethylene (PE), polypropylene (PP), polystyrene (PS), nylon, polyurethane (PU), polycarbonate (PC), polyoxymethylene (POM), and a mixture thereof;
said adhesive is in physical communication with a backing material, wherein said backing material is selected from the group consisting of tape, roller, mold, and a combination thereof; and
said adhesive is contacted with surfaces of said polycrystalline perovskite film with an applied pressure of about 1 Pa to about 100 MPa.

### Claim at position 24

37-44. (canceled)

### Claim 45 (depends on 29)

The surface treatment method of claim 29, wherein said method produces a polycrystalline perovskite film with improved stability for use as an active material in a semiconductor device, wherein:
said semiconductor device is selected from the group consisting of solar cell, light emitting diode, photodiode, photoelectrochemical cell, photoresistor, phototransistor, photomultiplier, photoelectric cell, electrochromic cell, and radiation detector; or
said semiconductor device is a solar cell and said method improves the power conversion efficiency of said solar cell.

### Claim at position 26

46-52. (canceled)

### Claim 53 (depends on 16, 29)

A method of preparing the solar cell of claim 16, comprising:
disposing an active layer comprising a polycrystalline perovskite film on a transparent conductive oxide layer; and
disposing a conductive electrode layer on said active layer; wherein said method further comprises the surface treatment method of claim 29.

### Claim 54

(canceled)

### Claim 55 (depends on 1)

A surface treatment method for removing one or more surface defect layers from the polycrystalline perovskite film of claim 1, comprising:
a) contacting an abrasive or soft polishing pad with one or more surfaces of a polycrystalline perovskite film with a pressure about 1 Pa to about 100 MPa; and
b) removing loose material from said polycrystalline perovskite film surfaces, comprising applying a solvent to surfaces of said polycrystalline perovskite film,
wherein said solvent is selected from the group consisting of toluene (TL), ethyl acetate (EA), diethyl ether (DE), dichloromethane (DCM), hexane, and a mixture thereof;
wherein a and b are carried out one or more times to remove said one or more surface defect layers;
wherein said polycrystalline perovskite film is rotating relative to said abrasive or soft polishing pad;
wherein said one or more surface defect layers comprise a depth of about 10 nm to about 1000 μm;
wherein said method is scalable; and
optionally, wherein said method comprises first contacting said abrasive with one or more surfaces of said polycrystalline perovskite film, and then contacting said soft polishing pad with said one or more surfaces of said polycrystalline perovskite film.

### Claim 56 (depends on 55)

The surface treatment method of claim 55, wherein said abrasive comprises particles of SiO2 or Al2O3having a diameter of about 1 μm to about 30 μm.

### Claim at position 31

57-58. (canceled)

### Claim 59 (depends on 55)

The surface treatment method of claim 55, wherein:
said soft polishing pad has a thickness of about 100 μm to about 5 mm;
said soft polishing pad is flexible;
said soft polishing pad has a porous surface, wherein said porous surface has a Shore O type hardness of about 30 to about 80; and
said soft polishing pad or said porous surface comprises a material selected from the group consisting of polyurethane (PU), polycarbonate (PC), polyester, cotton, silk, rubber, cellulose, nylon, and a mixture thereof.

### Claim at position 33

60-76. (canceled)

### Claim 77 (depends on 55)

The surface treatment method of claim 55, wherein said method produces a polycrystalline perovskite film with improved stability for use as an active material in a semiconductor device, wherein:
said semiconductor device is selected from the group consisting of solar cell, light emitting diode, photodiode, photoelectrochemical cell, photoresistor, phototransistor, photomultiplier, photoelectric cell, electrochromic cell, and radiation detector; or
said semiconductor device is a solar cell and said method improves the power conversion efficiency of said solar cell.

### Claim at position 35

78-84. (canceled)