Perovskite solar cell and preparation thereof

Abstract

The invention discloses a perovskite solar cell and preparation thereof, the perovskite solar cell comprises an electron transport layer located between an anode and a cathode, and the electron transport layer is composed of a first part of tin oxide (SnOx) and a second part of tin oxide. A method for preparing the perovskite solar cell includes depositing an electron transport layer having a first portion of tin oxide (SnOx) and a second portion of tin oxide on a surface-passivated perovskite active layer.

Description

TECHNICAL FIELD

[0001] The present invention relates to a perovskite solar cell, for example, in particular but not exclusively to a perovskite solar cell comprising an electron transport layer consisting of a first portion of tin oxide (SnO x ) and a second portion of tin oxide. The present invention also relates to the preparation of a perovskite solar cell. BACKGROUND

[0002] It is believed that the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has already surpassed many conventional thin-film solar technologies. However, typical PSCs comprise fragile interfaces, which pose challenges to them, particularly in achieving long-term stability. Some contact points can even degrade under various environmental stresses such as humidity, oxygen, temperature variation and illumination, leading to reduced cell performance and lifetime.

[0003] In inverted p-i-n PSCs, it is believed that fullerene electron transport layers (ETLs) are widely used, while the perovskite / electron transport layer (ETL) interface significantly contributes to efficiency loss, forming deep trap states. The high cost and poor mechanical properties associated with fullerene ETLs have driven the research for alternatives.

[0004] One possible solution is to replace fullerene with metal oxides. However, the high-temperature requirement for depositing metal oxides on perovskite, particularly hybrid perovskite, can be problematic due to the heat sensitivity of perovskite. While sputtering metal oxides on perovskite or direct atomic layer deposition (ALD) of metal oxides are alternative options for replacing fullerene with metal oxides, it is believed that the former can damage the perovskite surface, while the latter can lead to chemical reactions and interface barriers, resulting in PCE of the device below 1%.

[0005] Accordingly, the present invention seeks to obviate or at least mitigate such disadvantages by providing a new or otherwise improved perovskite solar cell (PSC), for example, a new or otherwise improved inverted PSC. SUMMARY

[0006] In a first aspect of the present invention, there is provided a perovskite solar cell comprising an electron transport layer located between an anode and a cathode, wherein the electron transport layer consists of a first portion of tin oxide (SnO x ) and a second portion of tin oxide.

[0007] In optional embodiments, the first portion of tin oxide (SnO x ) and the second portion of tin oxide have different stoichiometries.

[0008] Optionally, the SnOx The value of x is approximately 1.81 to 1.98.

[0009] Optionally, the first portion of tin oxide is disposed on the second portion of tin oxide.

[0010] In an optional embodiment, the tin oxide in the first and second portions has different thicknesses.

[0011] Optionally, the thickness of the first and second portions of tin oxide is in the range of about 2 nm to about 50 nm.

[0012] In an optional embodiment, the thickness of the first portion of tin oxide is less than the thickness of the second portion.

[0013] In the optional implementation scheme, SnO in the first part x x is less than the second part SnO x x.

[0014] Optionally, SnO in Part 1 x The x value is approximately 1.83, and in the second part, SnO... x The value of x is approximately 1.96.

[0015] Optionally, the thickness of the first part is about 2 nm to about 10 nm, and the thickness of the second part is about 15 nm to about 50 nm.

[0016] In an optional embodiment, the perovskite solar cell further includes a passivation layer located between the electron transport layer and the perovskite active layer.

[0017] Optionally, the passivation layer is disposed below the first portion of the electron transport layer.

[0018] Optionally, the passivation layer comprises phenylethylamine salts and perylene diimide-based compounds.

[0019] Optionally, the phenylethylamine salt is selected from the group consisting of: PEAI (phenylethyl ammonium iodide), PEABr (phenylethyl ammonium bromide), PEACl (phenylethyl ammonium chloride), mF-PEAI (m-fluorophenylethyl ammonium iodide), oF-PEAI (o-fluorophenylethyl ammonium iodide), CF3-PEAI (trifluoromethylphenylethyl ammonium iodide), CH3O-PEAI (4-methoxyphenylethyl ammonium iodide) and 4F-PEAI (4-fluorophenylethyl ammonium iodide) and combinations thereof.

[0020] Optionally, the perylene diimide-based compound is selected from the group consisting of PDINN (N,N'-bis{3-[3-(dimethylamino)propylamino]propyl}perylene-3,4,9,10-tetracarboxylic diimide), PDIN (N,N'-bis{3-[3-(dimethylamino)propyl]amino}perylene-3,4,9,10-tetracarboxylic diimide), PDINO (N,N'-bis{3-[3-(dimethylamino)propyl]amino}perylene-3,4,9,10-tetracarboxylic diimide N-oxide), NDI-N (N,N'-bis{3-[3-(dimethylamino)propyl]amino}naphthalene-1,4,5,8-tetracarboxylic diimide), and combinations thereof.

[0021] Optionally, the molar concentration ratio of the phenethylamine salt and the perylene diimide-based compound is about 4: 1 to about 1:4.

[0022] In optional embodiments, the perovskite active layer comprises a perovskite material of the formula Cs x MA y FA 1-x-y Sn z Pb 1-z I 3-m Br m wherein x is 0-0.5, y is 0-0.5, z is 0-0.5, and m is 0-1.5.

[0023] Optionally, the perovskite material is doped with a hole transporting material selected from the group consisting of 2PACz, MeO-2PACz (methoxy-2PACz), Me-4PACz (methyl-4PACz), Br-2PACz (bromo-2PACz), CbzBF, 4PADBC, and CbzBT.

[0024] In optional embodiments, the anode comprises a conductive material deposited on a transparent substrate, the conductive material selected from the group consisting of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), niobium-doped titanium dioxide (NTO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), and combinations thereof.

[0025] In optional embodiments, the cathode comprises a metal selected from the group consisting of gold, silver, copper, aluminum, nickel, and combinations thereof.

[0026] Optionally, the perovskite solar cell is an inverted perovskite solar cell.

[0027] In a second aspect of the application, there is provided a method of making a perovskite solar cell according to the first aspect, comprising depositing a surface passivated perovskite active layer on a transparent substrate, depositing a first portion of tin oxide (SnO xa step of forming an electron transport layer consisting of a first portion of tin oxide and a second portion of tin oxide.

[0028] In optional embodiments, the depositing is by way of atomic layer deposition.

[0029] Optionally, the atomic layer deposition comprises the steps of: (a) contacting the surface-passivated perovskite active layer with a gas-phase tin pulse in a reaction space, followed by contacting the surface-passivated perovskite active layer with a gas-phase oxygen pulse in the reaction space, to form a first portion of tin oxide; and (b) contacting the first portion of tin oxide with a gas-phase tin pulse in the reaction space, followed by contacting the first portion of tin oxide with a gas-phase oxygen pulse in the reaction space, to form a second portion of tin oxide.

[0030] Optionally, step (a) is repeated for 10 to 50 cycles.

[0031] Optionally, step (b) is repeated for 50 cycles to 500 cycles.

[0032] Optionally, in step (a), the gas-phase tin pulse is contacted with the surface-passivated perovskite active layer for about 120 ms to about 400 ms.

[0033] Optionally, in step (a), the gas-phase oxygen pulse is contacted with the surface-passivated perovskite active layer for about 5 ms to about 20 ms.

[0034] Optionally, in step (b), the gas-phase tin pulse is contacted with the first portion of tin oxide for about 20 ms to about 100 ms.

[0035] Optionally, in step (b), the gas-phase oxygen pulse is contacted with the first portion of tin oxide for about 10 ms to about 40 ms.

[0036] In optional embodiments, step (a) and step (b) each further comprise a step of purging the reaction space.

[0037] Optionally, the step of purging the reaction space consists of purging after the gas-phase tin pulse is applied and before the gas-phase oxygen pulse is applied; and purging after the gas-phase oxygen pulse is applied.

[0038] In optional embodiments, purging the reaction space in step (a) is different between the first cycle and the second cycle.

[0039] Optionally, the number of cycles is divided into a first group, a second group, and a third group, and the time of purging the reaction space increases from the first group to the third group.

[0040] In optional embodiments, the time of purging the reaction space after the gas-phase tin pulse is applied in step (a) is about 20 seconds.

[0041] Optionally, the atomic layer deposition is performed at a temperature of about 85 °C to about 125 °C.

[0042] Optionally, the gas phase tin comprises tetra(dimethylamino)tin and the gas phase oxygen comprises water.

[0043] In an optional embodiment, the method further comprises the steps of: (i) providing an anode comprising an electrically conductive material; (ii) depositing a perovskite active layer on the anode; (iii) subjecting the perovskite active layer to a surface passivation treatment; and (iv) providing a cathode on the electron transport layer by means of thermal evaporation.

[0044] Optionally, step (ii) comprises the steps of: providing a precursor solution comprising: a compound of formula Cs x MA y FA 1-x- y Sn z Pb 1-z I 3-m Br m CsI, FAI, MAI, MABr, PbBr2, PbI2and SnI2, wherein x is 0-0.5, y is 0-0.5, z is 0-0.5, m is 0-1.5, and a hole transport material; spin coating the precursor solution on the anode; and annealing the spin-coated anode to form a perovskite active layer thereon.

[0045] Optionally, the concentration of the hole transport material in the precursor solution is about 0.15 mg / mL to about 1.2 mg / mL.

[0046] Optionally, step (iii) comprises the steps of: spin coating a surface passivation solution comprising a phenethylamine salt and a perylenediimide-based compound on the perovskite active layer obtained in step (ii); and annealing the spin-coated perovskite active layer to form a passivation layer thereon.

[0047] Optionally, the initial concentration of the phenethylamine salt is about 0.5 mg / mL to about 4 mg / mL and the initial concentration of the perylenediimide-based compound is about 0.5 mg / mL to about 8 mg / mL.

[0048] Optionally, the volume ratio of the phenethylamine salt and the perylenediimide-based compound is 1 : 1. BRIEF DESCRIPTION OF DRAWINGS

[0049] The present application will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic illustration of a perovskite solar cell illustrating an exemplary embodiment according to the present application; Figure 2is a schematic illustration illustrating embodiments according to the present application; Figure 3 SnO2 films obtained with different TDMASn:H2O ALD dosing ratios x XPS spectra of the films with H2O fixed at 20 ms, a.u., arbitrary units; Figure 4 SnO2 films obtained with different TDMASn:H2O ALD flow ratios (H2O fixed at 20 ms) x Sn 3d5 / 2 peak in the XPS spectra of the films; Figure 5 SnO2 films obtained with different TDMASn:H2O ALD flow ratios (H2O fixed at 20 ms) x O 1s peak in the XPS spectra of the films; Figure 6 SnO2 films obtained with different TDMASn:H2O ALD flow ratios (H2O fixed at 20 ms) analyzed by XPS x x values of SnO2 films; Figure 7 Summary of SnO2 films x Table of fitting parameters of Sn 3d5 / 2 and O 1s peaks in the XPS spectra of the films; Figure 8 SnO2 films obtained with different TDMASn:H2O ALD dosing ratios (H2O fixed at 20 ms) and different number of ALD cycles x Effect of the transport layer on the device performance; Figure 9A ALD gas flow monitoring during the fabrication of SnO2 transport layers x Effect of the transport layer on the device performance; Figure 9B Performance of the best devices with the structure ITO / active layer / passivation layer / SnO2 x (TDMASn:H2O 25:20) / Ag J-V curve; Figure 9C Statistical histogram of the PCE distribution of the devices with the structure ITO / active layer / passivation layer / SnO2 x (TDMASn:H2O 25:20) / Ag Figure 10A ALD gas flow monitoring during the fabrication of SnO2 transport layers x Effect of the transport layer on the device performance; Figure 10B Statistical histogram showing PCE distribution of devices with ITO / active layer / passivation layer / SnO x (TDMASn:H2O 50:20) / Ag structure; J-V Figure 10C Statistical histogram showing PCE distribution of devices with ITO / active layer / passivation layer / SnO x (TDMASn:H2O 100:20) / Ag structure; Figure 11A ALD gas flow monitoring during fabrication of SnO x transport layer with TDMASn:H2O ALD flow ratio of 100:20, thickness of 200 cycles; Figure 11B Statistical histogram showing PCE distribution of devices with ITO / active layer / passivation layer / SnO x (TDMASn:H2O 100:20) / Ag structure; J-V Figure 11C Statistical histogram showing PCE distribution of devices with ITO / active layer / passivation layer / SnO x (TDMASn:H2O 100:20) / Ag structure; Figure 12A ALD gas flow monitoring during fabrication of SnO x transport layer with TDMASn:H2O ALD flow ratio of 150:20, thickness of 200 cycles; Figure 12B Statistical histogram showing PCE distribution of devices with ITO / active layer / passivation layer / SnO x (TDMASn:H2O 150:20) / Ag structure; J-V Figure 12C Statistical histogram showing PCE distribution of devices with ITO / active layer / passivation layer / SnO x (TDMASn:H2O 150:20) / Ag structure; Figure 13A ALD gas flow monitoring during fabrication of SnO x transport layer with TDMASn:H2O ALD flow ratio of 200:20, thickness of 200 cycles; Figure 13B Statistical histogram showing PCE distribution of devices with ITO / active layer / passivation layer / SnO x ​​​Statistical histogram of PCE distribution for the best performing devices of the structure of ITO / active layer / passivation layer / SnO J-V Curves; Figure 13C Devices with ITO / active layer / passivation layer / SnO x Statistical histogram of PCE distribution for the devices of the structure of ITO / active layer / passivation layer / SnO Figure 14A Devices with ITO / active layer / passivation layer / SnO x ALD gas flow monitoring during SnO Figure 14B Devices with ITO / active layer / passivation layer / SnO x Statistical histogram of PCE distribution for the best performing devices of the structure of ITO / active layer / passivation layer / SnO J-V Curves; Figure 14C Devices with ITO / active layer / passivation layer / SnO x Statistical histogram of PCE distribution for the devices of the structure of ITO / active layer / passivation layer / SnO Figure 15 Statistical distribution of V x , J OC , FF for devices with ITO / active layer / passivation layer / SnO SC / Ag structure at different TDMASn:H2O ALD flow ratios; Figure 16 Statistical distribution of PCE for the best performing devices at different SnO x transport layer thicknesses; J-V Curves; Figure 17 Statistical distribution of PCE for the devices at different SnO x transport layer thicknesses; Figure 18A Devices with ITO / active layer / passivation layer / 200-cycle SnO x Statistical histogram of PCE distribution for the best performing devices of the structure of ITO / active layer / passivation layer / SnO J-V Curves; Figure 18B Devices with ITO / active layer / passivation layer / 200-cycle SnO xPerformance of the best devices of the structure ITO / active layer / passivation layer / 200 cycles SnO J-V Curves; Figure 18C shows the peak force infrared (PFIR) mapping of the active layer with and without passivation layer. The PFIR mapping shows the intensity and distribution of the PDINN molecules C=0 stretching vibration at 1650 cm x Performance of the best devices of the structure ITO / active layer / passivation layer / 200 cycles SnO J-V Curves; Figure 18D shows the peak force infrared (PFIR) mapping of the active layer with and without passivation layer. The PFIR mapping shows the intensity and distribution of the PDINN molecules C=0 stretching vibration at 1650 cm x Performance of the best devices of the structure ITO / active layer / passivation layer / 200 cycles SnO J-V Curves; Figure 19 shows the peak force infrared (PFIR) mapping of the active layer with and without passivation layer. The PFIR mapping shows the intensity and distribution of the PDINN molecules C=0 stretching vibration at 1650 cm -1 Performance of the best devices of the structure ITO / active layer / passivation layer / 200 cycles SnO Figure 20 shows the peak force infrared (PFIR) mapping of the active layer with and without passivation layer. The PFIR mapping shows the intensity and distribution of the PDINN molecules C=0 stretching vibration at 1650 cm x Performance of the best devices of the structure ITO / active layer / passivation layer / 200 cycles SnO J-V Curves; Figure 21 shows the peak force infrared (PFIR) mapping of the active layer with and without passivation layer. The PFIR mapping shows the intensity and distribution of the PDINN molecules C=0 stretching vibration at 1650 cm 60 Performance of the best devices of the structure ITO / active layer / passivation layer / 200 cycles SnO J-V Curves; Figure 22 shows the peak force infrared (PFIR) mapping of the active layer with and without passivation layer. The PFIR mapping shows the intensity and distribution of the PDINN molecules C=0 stretching vibration at 1650 cm 60 BCP / Ag or ITO / ZnO / SnO x Ag of single electron devices; Figure 23A shows the UV-Vis spectra of the perovskite film and passivated perovskite film; Figure 23B shows the Tauc plot of the perovskite film; Figure 23C shows the Tauc plot of the passive perovskite film; Figure 23D shows the UV-Vis spectra of the SnO x(i) and SnO x films; Figure 23E SnO is shown x Tauc diagram of the membrane; Figure 23F SnO is shown x(i) Tauc diagram of the membrane; Figure 24A The UPS spectrum of the perovskite film is shown; Figure 24B The Tauc diagram of the perovskite film is shown; Figure 24C SnO is shown x Tauc diagram of the membrane; Figure 24D SnO is shown x UPS spectrum of the membrane; Figure 24E The energy level diagram of ETL / perovskite is shown. C 60 The LUMO level is generally around -4.3 eV; Figure 25 The results show SnO under different TDMASn:H2O ALD feed ratios (H2O fixed at 20 ms) and varying ALD cycles. x(i) The effect of the intermediate layer on device performance; Figure 26 The diagram illustrates SnO prepared using different TDMASn:H2O ALD flow ratios. x(i) The best performing device in the intermediate layer J-V curve; Figure 27 The use of SnO is shown x(i) Statistical distribution of performance parameters of devices using different ALD methods in the intermediate layer; Figure 28 SnO is shown x(i) ALD gas flow monitoring in the intermediate layer; Figure 29 This diagram shows a SnO layer with ITO / active layer / passivation layer and 30 cycles. x(i) (TDMASn:H2O AlD ratio is 200:20) Intermediate layer / 300 cycles of SnO x SnO-based structure with a TDMASn:H2O ALD ratio of 50:20) / Ag x The best performing device J-V curve; Figure 30 It shows SnO-based x MPP of the device; Figure 31 It shows SnO-based x The EQE curve and integral J of the device SC; Figure 32 Statistical distributions of device performance parameters (V x , J OC , FF and PCE) are shown for SnO SC -based devices; Figure 33A Current vs. voltage curves are shown for devices with the structure ITO / active layer / BCP / Ag; J-V Figure 33B Current vs. voltage curves are shown for devices with the structure ITO / active layer / passivation layer / SnO x (TDMASn:H2O 50:20) / Ag; J-V Figure 33C Current vs. voltage curves are shown for devices with the structure ITO / active layer / mF-PEAI / SnO x (TDMASn:H2O 50:20) / Ag; J-V Figure 33D Current vs. voltage curves are shown for devices with the structure ITO / active layer / mF-PEAI / SnO x(i) (TDMASn:H2O 200:20) / SnO x (TDMASn:H2O 50:20) / Ag; J-V Figure 33E Current vs. voltage curves are shown for devices with the structure ITO / active layer / passivation layer / PDINN / SnO x (TDMASn:H2O 50:20) / Ag; J-V Figure 33F Current vs. voltage curves are shown for devices with the structure ITO / active layer / PDINN / SnO x (TDMASn:H2O 200:20) / SnO x (TDMASn:H2O 50:20) / Ag; J-V Figure 33G Current vs. voltage curves are shown for devices with the structure ITO / active layer / mF-PEAI+PDINN / BCP / Ag; J-V Figure 33H Current vs. voltage curves are shown for devices with the structure ITO / active layer / mF-PEAI+PDINN / SnO x (TDMASn:H2O 50:20) / Ag; J-V Figure 33I ​​​​​​​​It shows a structure with ITO / active layer / mF-PEAI+PDINN / C 60 Devices with a / BCP / Ag structure J-V curve; Figure 33J This illustrates a structure with ITO / active layer / mF-PEAI+PDINN / SnO x(i) (TDMASn:H2O = 200:20) / SnO x Devices with a structure of (TDMASn:H2O = 50:20) / Ag J-V curve; Figure 34 The results show SnO obtained using different TDMA Sn source pulse times (H2O source pulse time fixed at 20 ms). x(i) The intermediate layer EQE-EL, V TFL and PL strength; Figure 35 The SnO obtained with different TDMASn:H2O ALD flow ratios is shown. x(i) The intermediate layer is based on SnO x The EQE-EL of the device; Figure 36A SnO-free x(i) Intermediate layer single-electron device (ITO / SnO2 (spin-coated) / active layer / passivation layer / SnO) x(i) (ALD) / SnO x SCLC of (ALD) / Ag); Figure 36B The SnO obtained with a TDMASn:H2O ALD flow ratio of 25:20 is shown. x(i) Intermediate layer single-electron device (ITO / SnO2 (spin-coated) / active layer / passivation layer / SnO) x(i) (ALD) / SnO x SCLC of (ALD) / Ag); Figure 36C The SnO obtained with a TDMASn:H2O ALD flow ratio of 50:20 is shown. x(i) Intermediate layer single-electron device (ITO / SnO2 (spin-coated) / active layer / passivation layer / SnO) x(i) (ALD) / SnO x SCLC of (ALD) / Ag); Figure 36D The SnO obtained with a TDMASn:H2O ALD flow ratio of 100:20 is shown. x(i) Intermediate layer single-electron device (ITO / SnO2 (spin-coated) / active layer / passivation layer / SnO)x(i) (ALD) / SnO x SCLC of (ALD) / Ag); Figure 36E The SnO obtained with a TDMASn:H2O ALD flow ratio of 150:20 is shown. x(i) Intermediate layer single-electron device (ITO / SnO2 (spin-coated) / active layer / passivation layer / SnO) x(i) (ALD) / SnO x SCLC of (ALD) / Ag); Figure 36F The SnO obtained with a TDMASn:H2O ALD flow ratio of 200:20 is shown. x(i) Intermediate layer single-electron device (ITO / SnO2 (spin-coated) / active layer / passivation layer / SnO) x(i) (ALD) / SnO x SCLC of (ALD) / Ag); Figure 36G The SnO obtained with a TDMASn:H2O ALD flow ratio of 250:20 is shown. x(i) Intermediate layer single-electron device (ITO / SnO2 (spin-coated) / active layer / passivation layer / SnO) x(i) (ALD) / SnO x SCLC of (ALD) / Ag); Figure 37 The SnO obtained with different TDMASn:H2O ALD flow ratios is shown. x(i) The active layer of the intermediate layer / SnO x(i) / SnO x PL spectrum of the membrane; Figure 38 The membrane (including the original SnO) is shown. x PL mapping of the active layer (from SnO) x (side incidence); Figure 39 The membrane (including SnO) is shown. x / SnO x(i) PL mapping of the active layer (from SnO) x (side incidence); Figure 40 SEM images of the membrane surface under different stacking conditions are shown; Figure 41 ITO / perovskite / SnO was shown x(i) / SnO x SEM cross-sectional image of the / Ag device; Figure 42shows thickness profile analysis of SnO2 film deposited using 150 ALD cycles x(i) The average thickness of the SnO2 film was 18.3 nm, which means that after 30 cycles the thickness of the SnO2 film was about 3.7 nm. x(i) The average thickness of the SnO2 film was 18.3 nm, which means that after 30 cycles the thickness of the SnO2 film was about 3.7 nm. x(i) The average thickness of the SnO2 film was 18.3 nm, which means that after 30 cycles the thickness of the SnO2 film was about 3.7 nm. Figure 43A shows thickness profile analysis of SnO2 film deposited using 300 ALD cycles x The average thickness of the SnO2 film was 18.3 nm, which means that after 30 cycles the thickness of the SnO2 film was about 3.7 nm. x The average thickness of the SnO2 film was 18.3 nm, which means that after 30 cycles the thickness of the SnO2 film was about 3.7 nm. Figure 43B shows thickness profile analysis of SnO2 film deposited using 600 ALD cycles x The average thickness of the SnO2 film was 18.3 nm, which means that after 30 cycles the thickness of the SnO2 film was about 3.7 nm. Figure 43C shows thickness profile analysis of SnO2 film deposited using 900 ALD cycles x The average thickness of the SnO2 film was 18.3 nm, which means that after 30 cycles the thickness of the SnO2 film was about 3.7 nm. Figure 44A shows graphical illustration of simulated charge distribution (corresponding to CBM) at the pristine SnO2 / perovskite interface; Figure 44B shows graphical illustration of simulated charge distribution (corresponding to CBM) at the SnO2(V x(i) ) / perovskite interface; O Figure 44C shows graphical illustration of simulated charge distribution (corresponding to CBM) at the SnO2 / PDINN / perovskite interface; Figure 44D shows graphical illustration of simulated charge distribution (corresponding to CBM) at the SnO2(V x(i) ) / PDINN / perovskite interface; O Figure 45A shows calculated pDOS plot for the pristine SnO2 / perovskite interface; Figure 45B shows calculated pDOS plot for the SnO2(V x(i) ) / perovskite interface; O Figure 45C shows calculated pDOS plot for the SnO2 / PDINN / perovskite interface; Figure 45D shows calculated pDOS plot for the SnO2(V x(i) ) / PDINN / perovskite interface; O Figure 46 ​​​​DFT structure optimization of Sn02 / perovskite interface and Sn02 / PDINN / perovskite interface are shown; Figure 47A Computed pDOS curves of Sn02 / perovskite interface are shown; Figure 47B Computed pDOS curves of Sn02 / perovskite interface are shown; x(i) (V O ) / perovskite interface are shown; Figure 47C Computed pDOS curves of Sn02 / PDINN / perovskite interface are shown; Figure 47D Computed pDOS curves of Sn02 / perovskite interface are shown; x(i) (V O ) / PDINN / perovskite interface are shown; Figure 48A Computed pDOS curves of Sn02 / PDINN / perovskite interface are shown, with Sn02extracted alone; Figure 48B Computed pDOS curves of Sn02 / PDINN / perovskite interface are shown, with Sn02+ PDINNextracted alone; Figure 48C Computed pDOS curves of Sn02 / PDINN / perovskite interface are shown, with PDINNextracted alone; Figure 49A Computed pDOS curves of Sn02 / perovskite interface are shown; x(i) (V O ) / PDINN / perovskite interface are shown, with Sn02extracted alone; x(i) (V O ); Figure 49B Computed pDOS curves of Sn02 / perovskite interface are shown; x(i) (V O ) / PDINN / perovskite interface are shown, with Sn02+ PDINNextracted alone; x(i) (V O ); Figure 49C Computed pDOS curves of Sn02 / perovskite interface are shown; x(i) (V O ) / PDINN / perovskite interface are shown, with PDINNextracted alone; Figure 50A I3dcore levels of perovskite, perovskite / Sn02 x , and perovskite / PDINN / Sn02 x are shown; Figure 50B Computed pDOS curves of Sn02 / perovskite interface are shown, with PDINNextracted alone;Figure 50A The I 3d FWHM; Figure 50C Perovskite, perovskite / SnO were shown. x and perovskite / PDINN / SnO x The Pb 4f nuclear energy level; Figure 50D It shows the corresponding Figure 50C The binding energy of Pb 4f; Figure 51A SnO is shown x(i) (V O A graphical illustration of the simulated charge distribution at the PDINN / perovskite interface (corresponding to the CBM level); Figure 51B It shows Figure 51A Top view; Figure 51C SnO is shown x(i) (V O A graphical illustration of the simulated charge distribution at the ) / mF-PEAI / perovskite interface (corresponding to the CBM level); Figure 51D It shows Figure 51C Top view; Figure 51E SnO is shown x(i) (V O A graphical illustration of the simulated charge distribution at the perovskite interface (corresponding to the CBM level). Figure 51F It shows Figure 51E Top view; Figure 52 The operational stability of the device at 65°C is shown; Figure 53 A table summarizing the device operational stability (MPP tracking at temperatures above 50°C) of representative nip and pin PSCs; Figure 54 The results show that under heating at 85°C and one day of sunlight, SnO-based x Devices and C-based 60 Stability comparison of / BCP devices; Figure 55A The TOF-SIMS characterization of the primitive device without stability testing is shown; Figure 55B It shows the corresponding Figure 54 TOF-SIMS characterization of the device following operational stability testing; Figure 56A This shows a C-based system without stability testing. 60TOF-SIMS characterization of devices based on SnO Figure 56B TOF-SIMS characterization of devices based on SnO 60 Figure 57A TOF-SIMS characterization of devices based on SnO x Figure 57B TOF-SIMS characterization of devices based on SnO x Figure 58 Evolution of efficiency of devices under repeated thermal cycling (-40°C to 85°C) in dark air (ISOS-T-3). Thermal cycling tests were performed using eight independent devices and the average performance change was obtained along with the SD as a measure of error; Figure 59 Evolution of efficiency of devices under storage in dark (ISOS-D-1) in indoor air conditions. Stability tests were performed using 10 to 14 independent devices and the average performance change was obtained along with the SD as a measure of error; Figure 60 Evolution of efficiency of devices based on SnO x in dark (ISOS-D-1) in indoor air conditions, unencapsulated and encapsulated; Figure 61 Evolution of efficiency of devices under damp heat testing (ISOS-D-3) in dark air at 85°C and 85% RH. Stability tests were performed using 10 to 14 independent devices and the average performance change was obtained along with the SD as a measure of error; Figure 62 Evolution of efficiency of devices based on SnO x under damp heat testing (ISOS-D-3) in dark air at 85°C and 85% relative humidity, unencapsulated and encapsulated; Figure 63 Evolution of efficiency of devices under light-on-light-off cycling testing (12 hours - 12 hours) with light-emitting diode (LED) lamps simulating 1 sun (ISOS-LC-1). Stability tests were performed using 10 to 14 independent devices and the average performance change was obtained along with the SD as a measure of error; Figure 64 ​​​The efficiency evolution of the device under outdoor conditions and storage in sunlight (ISOS-O-1) is shown. (The device was in an open-circuit state. Environmental data are from the Hong Kong Observatory, https: / / www.hko.gov.hk / tc / wxinfo / pastwx / mws2023 / mws202309.htm.). Stability tests were performed using 10 to 14 independent devices, and the average performance change and SD as a measure of error were obtained. Figure 65 The solar radiation intensity tracking curve is shown. (Data source: Hong Kong Observatory) https: / / www.hko.gov.hk / tc / wxinfo / pastwx / mws2023 / mws202309.htm ); Figure 66A For SnO-based x A schematic diagram of the self-packaging of the device; Figure 66B For comparison (based on C) 60 A schematic diagram of the physical packaging effect of the device; and Figure 67 The images show photographs of the original device (left), the device with a mask (middle), and the packaged device (right) before and after stability testing. Detailed Implementation

[0050] Unless the context clearly indicates otherwise, the forms “a” and “the” as used herein are intended to include both singular and plural forms.

[0051] The terms “example” or “illustrative” as used in this invention are intended to be used as instances, examples, or illustrations. Any aspect or design described as “illustrative” in this disclosure is not necessarily to be construed as being more preferred or advantageous than other aspects or designs. Rather, the use of the terms “example” or “illustrative” is intended to present concepts in a specific manner. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or indicated by the context, “X adopts A or B” is intended to mean any natural inclusive permutation. That is, “X adopts A or B” holds true in any of the foregoing cases if X adopts A, X adopts B, or X adopts both A and B.

[0052] As used herein, the term “about” is intended to refer to a value that deviates slightly from the values ​​described herein. Examples have been described throughout this disclosure.

[0053] Without being bound by theory, the inventors, through their own research, trial and error, have devised a strategy that can improve the performance and stability of perovskite solar cells, particularly inverted p-i-n perovskite solar cells. Specifically, the inventors have devised a solar cell construction that can avoid the use of a fullerene electron transport layer (ETL), eliminate deleterious chemical reactions at the perovskite / inorganic ETL interface, and can facilitate electron transport / electron extraction between the perovskite and the ETL. Advantageously, as explained in the latter part of this disclosure, the perovskite solar cells described herein can have a power conversion efficiency of at least 25%, can have a T 95 aging lifetime, etc.

[0054] In a first aspect of the present invention, a perovskite solar cell is provided that includes an electron transport layer positioned between an anode and a cathode, where the electron transport layer is composed of a first portion of tin oxide (SnO x ) and a second portion of tin oxide. The first portion of tin oxide can be disposed on the second portion of tin oxide. For example, depending on the type of perovskite solar cell, e.g., n-i-p type (i.e., direct type), p-i-n type (i.e., inverted type), etc., the first portion can be disposed on the bottom of the second portion or on the top of the second portion.

[0055] Specifically, the first portion of tin oxide and the second portion of tin oxide can have different stoichiometries. For example, in some embodiments, x of SnO x in the first portion and the second portion can be in the range of about 1.81 to 1.98, e.g., 1.81, 1.82, 1.83, 1.84, 1.85, 1.86,... 1.90, 1.91, 1.92, 1.93,... 1.96, 1.97, 1.98, etc. The first portion of tin oxide and the second portion of tin oxide can also have different thicknesses. For example, in some embodiments, the thickness of the first portion of tin oxide and the second portion of tin oxide is in the range of about 2 nm to about 50 nm, e.g., about 1.95 nm to about 50 nm, about 1.98 nm to about 50.1 nm, about 1.98 nm to about 49.8 nm, about 1.99 nm to about 50 nm, about 2.01 nm to about 50.2 nm, about 2.05 nm to about 50.3 nm, etc.

[0056] In some specific embodiments, the thickness of the first portion of tin oxide may be less than the thickness of the second portion of tin oxide. For example, the thickness of the first portion may be from about 2 nm to about 10 nm (e.g., 1.98 nm, 1.99 nm, 2 nm…2.05 nm…2.1 nm…3.1 nm…3.7 nm, 3.8 nm…5 nm…5.12 nm…6.2 nm…6.64 nm…9.8 nm…9.9 nm…10 nm…10.2 nm, etc.), and the thickness of the second portion may be from about 15 nm to about 50 nm (e.g., 14.8 nm, 14.9 nm, 15 nm…15.6 nm…16.3 nm…20 nm…25.1 nm…30 nm…32 nm…37 nm…38 nm…40 nm…54 nm…50 nm…50.2 nm, etc.).

[0057] In some other specific implementations, SnO in the first part x x may be smaller than the second part of SnO x x. For example, SnO in the first part x x is likely to be approximately 1.83, and in the second part SnO x x is likely to be approximately 1.96.

[0058] In some preferred embodiments, the thickness of the first portion of tin oxide is less than the thickness of the second portion, and the SnO in the first portion... x The x in the first part is less than the x in the second part. Unbound by theory, it is believed that when the SnO in the first part... x When the thickness and x of the first part are both smaller than those of the second part, oxygen defects (V0) may be induced within the electron transport layer. O (Defects), thereby increasing carrier transport between the perovskite active layer and the electron transport layer. Other details will be discussed later in this disclosure.

[0059] refer to Figure 1 An exemplary perovskite solar cell 100 is provided, comprising an electron transport layer 102 located between an anode 104 and a cathode 106, wherein the electron transport layer comprises a first portion of tin oxide 108 and a second portion of tin oxide 110. In this embodiment, the perovskite solar cell 100 may be an inverted perovskite solar cell. Therefore, the first portion of tin oxide 108 may be disposed at the bottom of the second portion of tin oxide 110. The first portion of tin oxide may have a different O:Sn stoichiometry compared to the second portion of tin oxide. Specifically, for example, an O:Sn stoichiometry of 1.96 (i.e., SnO) is provided. xCompared to the second part of tin oxide (with an x ​​value of 1.96), the first part of tin oxide can have a lower O:Sn stoichiometry, for example, 1.83 (i.e., SnO). x The x-value is 1.83. The first tin oxide portion may also have a different thickness compared to the second tin oxide portion, specifically a lower thickness. For example, the thickness of the first tin oxide portion may be about 2 nm, about 3 nm, about 3.7 nm, about 3.8 nm, about 5 nm, about 10 nm, etc.; while the thickness of the second tin oxide portion may be about 15 nm, about 25 nm, about 30 nm, about 35 nm, about 37 nm, about 38 nm, about 40 nm, about 50 nm, etc.

[0060] like Figure 1 As shown, the perovskite solar cell 100 may further include a passivation layer 112 located between the electron transport layer 102 and the perovskite active layer 114. Specifically, the passivation layer may be disposed below the first portion of the electron transport layer, for example, disposed in direct contact with the bottom of the first portion of the electron transport layer. Unbound by theory, on the one hand, it is believed that the passivation layer can passivate the perovskite surface, thereby forming a molecular passivation layer or a 2D perovskite layer, to prevent direct interaction with the first portion of tin oxide containing oxygen vacancy defects, thereby optimizing interfacial charge transfer and preventing structural mismatch. On the other hand, the passivation layer can also act as a buffer layer, thereby achieving atomic layer deposition of the electron transport layer by preventing H2O (the oxygen source of the electron transport layer ALD) from directly contacting and reacting with the perovskite active layer.

[0061] The passivation layer 112 can include a phenethylamine salt and a perylenediimide-based compound. Specifically, in some embodiments, the phenethylamine salt can be selected from the group consisting of PEAI (phenylethylammonium iodide), PEABr (phenylethylammonium bromide), PEACl (phenylethylammonium chloride), mF-PEAI (meta-fluorophenylethylammonium iodide), o-F-PEAI (ortho-fluorophenylethylammonium iodide), CF3-PEAI (trifluoromethylphenylethylammonium iodide), CH3O-PEAI (4-methoxyphenylethylammonium iodide), and 4F-PEAI (4-fluorophenylethylammonium iodide), and combinations thereof. In some embodiments, the perylenediimide-based compound can be selected from the group consisting of PDINN (N,N'-bis{3-[3-(dimethylamino)propylamino]propyl}perylene-3,4,9,10-tetracarboxylic diimide), PDIN (N,N'-bis{3-[3-(dimethylamino)propyl]amino}perylene-3,4,9,10-tetracarboxylic diimide), PDINO (N,N'-bis{3-[3-(dimethylamino)propyl]amino}perylene-3,4,9,10-tetracarboxylic diimide N-oxide), NDI-N (N,N'-bis{3-[3-(dimethylamino)propyl]amino}naphthalene-1,4,5,8-tetracarboxylic diimide), and combinations thereof.

[0062] The molar concentration ratio of the phenethylamine salt to the perylenediimide-based compound can be about 4: 1 to about 1 :4, such as about 1 : 1, about 1 : 1.5, about 1 :2, about 1 :3, about 1 :4, and the like.

[0063] The perovskite active layer 114 can include a perovskite material doped with a hole transport material. In other words, the perovskite active layer can be a single layer of co-deposited perovskite material and hole transport material. In some embodiments, the perovskite material can have the formula Cs x MA y FA 1-x-y Sn z Pb 1-z I 3-m Br m wherein x is 0-0.5, y is 0-0.5, z is 0-0.5, and m is 0-1.5. For example, in some specific embodiments, the perovskite material can be Cs 0.05 MA 0.5 FA 0.45 Sn 0.2 Pb 0.8 I3, Cs 0.05 FA 0.95 PbI 2.94 Br 0.06 , MA 0.5 FA 0.5 Sn0.5 Pb 0.5 I 2.25 Br 0.75 , Cs 0.3 FA 0.7 PbI 2.4 Br 0.6 , Cs 0.5 FA 0.5 Sn 0.5 Pb 0.5 I 1.5 Br 1.5 , FA PbI3, Cs 0.05 FA 0.95 PbI 2.94 Br 0.06 , etc. The hole transport material can be selected from the group consisting of 2PACz, MeO-2PACz (methoxy-2PACz), Me-4PACz (methyl-4PACz), Br-2PACz (bromo-2PACz), CbzBF, 4PADBC, and CbzBT, and combinations thereof. Without being bound by theory, it is believed that the use of such a perovskite active layer can simplify the manufacturing process of a perovskite solar cell.

[0064] Referring to Figure 1 , the anode 104 can be located below the perovskite active layer 114, specifically in direct contact with the bottom of the perovskite active layer. The anode 104 can include a conductive material deposited on a transparent substrate such as glass. In some embodiments, the conductive material can be selected from the group consisting of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), niobium-doped titanium dioxide (NTO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), and combinations thereof.

[0065] The cathode 106 can be located above the electron transport layer 102, specifically in direct contact with the top of the second portion of the electron transport layer. The cathode can include a metal selected from the group consisting of gold, silver, copper, aluminum, nickel, and combinations thereof.

[0066] A method for preparing a perovskite layer as described herein is now disclosed. The method can include the step of depositing an electron transport layer consisting of a first portion of tin oxide (SnO x ) and a second portion of tin oxide on a surface passivated perovskite active layer. Specifically, the deposition can be by way of atomic layer deposition.

[0067] In some embodiments, atomic layer deposition can include the following steps: (a) contacting the surface passivated perovskite active layer with a gas phase tin pulse in a reaction space, followed by contacting the surface passivated perovskite active layer with a gas phase oxygen pulse in the reaction space to form a first portion of tin oxide; and (b) contacting the first portion of tin oxide with a gas phase tin pulse in the reaction space, followed by contacting the first portion of tin oxide with a gas phase oxygen pulse in the reaction space to form a second portion of tin oxide. As used herein, the term "reaction space" generally refers to a reaction chamber or a defined volume therein, wherein conditions can be adjusted to achieve atomic layer deposition.

[0068] As mentioned herein, in some embodiments, the thickness of the first portion of tin oxide can be less than the thickness of the second portion. Without being bound by theory, it is believed that the deposition thickness can be adjusted by the number of deposition cycles. Specifically, it is believed that the fewer the number of deposition cycles, the less the thickness of the resulting layer. Thus, in embodiments where the thickness of the first portion of tin oxide is less than the thickness of the second portion, the number of deposition cycles in step (a) can be less than the number of deposition cycles in step (b). For example, step (a) can be repeated for 10 cycles to 50 cycles (e.g., 15 cycles... 18 cycles... 30 cycles... 50 cycles, etc.), while step (b) can be repeated for 50 cycles to 500 cycles (e.g., 120 cycles... 200 cycles... 240 cycles... 280 cycles... 320 cycles... 400 cycles, etc.).

[0069] Also as mentioned herein, in some embodiments, x in the first portion can be less than x in the second portion. Without being bound by theory, it is believed that the value of x (i.e., the O:Sn stoichiometry) can be adjusted by the feed ratio (or dosing ratio) of the gas phase tin pulse and the gas phase oxygen pulse. For example, in the first portion, the SnO x x ​In these embodiments where x of the first portion is less than x of the second portion, the pulse of gas-phase tin can be in contact with the surface-passivated perovskite active layer in step (a) for about 120 ms to about 400 ms, while the pulse of gas-phase oxygen can be in contact with the surface-passivated perovskite active layer in step (a) for about 5 ms to about 20 ms. In other words, the feed ratio (or dosing ratio) of the pulse of gas-phase tin to the pulse of gas-phase oxygen in step (a) can be about 120 ms - 400 ms : 5 ms - 20 ms (e.g., 120 ms : 10 ms, 180 ms : 5 ms, 200 ms : 20 ms, 300 ms : 20 ms, 400 ms : 10 ms, etc.). Similarly, when performing step (b), the value of x (i.e., the O:Sn stoichiometry) of the second portion can be adjusted by the feed ratio (or dosing ratio) of the pulse of gas-phase tin to the pulse of gas-phase oxygen. For example, in these embodiments, the pulse of gas-phase tin can be in contact with the first portion of tin oxide in step (b) for about 20 ms to about 100 ms, while the pulse of gas-phase oxygen can be in contact with the surface-passivated perovskite active layer in step (b) for about 10 ms to about 40 ms. In other words, the feed ratio (or dosing ratio) of the pulse of gas-phase tin to the pulse of gas-phase oxygen in step (b) can be about 20 ms - 100 ms : 10 ms - 40 ms (e.g., 20 ms : 10 ms, 50 ms : 20 ms, 50 ms : 30 ms, 100 ms : 20 ms, 100 ms : 40 ms, etc.).

[0070] The atomic layer deposition method described herein can further include a step of purging the reaction space in either step (a) or step (b). In particular, the step of purging the reaction space can consist of purging after applying the pulse of gas-phase tin and before applying the pulse of gas-phase oxygen; and purging after applying the pulse of gas-phase oxygen. For example, in each cycle of step (a), after applying the pulse of gas-phase tin according to the feed / dosing times described herein, the reaction space can be purged with an inert gas (e.g., nitrogen or argon) before applying the pulse of gas-phase oxygen to remove excess / unreacted gas-phase tin and reaction byproducts from the reaction space. Similarly, after applying the pulse of gas-phase oxygen according to the feed / dosing times described herein, the reaction space can be purged with an inert gas (e.g., nitrogen or argon) before starting the next cycle or the next step (i.e., step (b)) to remove excess / unreacted gas-phase oxygen and reaction byproducts from the reaction space.

[0071] Similarly, for each cycle of step (b), after the application of the gas phase tin pulse according to the feed / dosing time described herein, the reaction space can be purged with the aid of an inert gas (e.g. nitrogen or argon) to remove excess / unreacted gas phase tin and reaction byproducts from the reaction space, before the application of the gas phase oxygen pulse. After the application of the gas phase oxygen pulse according to the feed / dosing time described herein, the reaction space can be purged with the aid of an inert gas (e.g. nitrogen or argon) to remove excess / unreacted gas phase oxygen and reaction byproducts from the reaction space, before the start of the next cycle.

[0072] In some embodiments, the purging of the reaction space in step (a) can remain unchanged between the first cycle and the second cycle. For example, the time of purging the reaction space after the application of the gas phase tin pulse in step (a) can be the same in the first cycle and the second cycle, e.g. assuming the time of purging the reaction space after the application of the gas phase tin pulse in step (a) is about 20 seconds, then in the first cycle and the second cycle, the time of purging the reaction space after the application of the gas phase tin pulse will be about 20 seconds.

[0073] In some other embodiments, the purging of the reaction space after the application of the gas phase tin pulse in step (a) can be different between the first cycle and the second cycle. In these embodiments, the number of cycles can be divided into three or more groups, e.g. a first group, a second group and a third group, and the time of purging the reaction space can increase from the first group to the third group. For example, assuming the time of purging the reaction space after the application of the gas phase tin pulse in step (a) is about 20 seconds, and step (a) is repeated for 30 cycles, then the 30 cycles can be divided into three cycle groups (e.g. first group = first 10 cycles; second group = 11th-20th cycles; third group = 21st-30th cycles), and the time of purging the reaction space in each cycle group increases in a gradient (e.g. first 10 cycles: 6 seconds; 11th-20th cycles: 13 seconds; 21st-30th cycles: 20 seconds).

[0074] Without being bound by theory, it is believed that in addition to the feed ratio of the gas phase tin (i.e. gaseous tin source) and the gas phase oxygen (i.e. gaseous oxygen source), the adjustment of the time of purging the reaction space after the application of the gas phase tin pulse in step (a) can facilitate the introduction of oxygen vacancies in the first portion of the electron transport layer. In particular, it is believed that the shorter the time of purging the reaction space after the application of the gas phase tin pulse in step (a), the higher the likelihood of oxygen vacancies occurring in the first portion of the electron transport layer. The details of this reaction mechanism will be discussed in the later part of this disclosure.

[0075] In some embodiments, atomic layer deposition can be performed at a temperature of about 85 °C to about 125 °C. For example, atomic layer deposition can be performed at a temperature of about 85 °C (e.g., 83 °C...83.5 °C...83.8 °C...84.2 °C...84.6 °C...85 °C...85.2 °C, etc.), about 95 °C (e.g., 93 °C...93.5 °C...93.8 °C...94.2 °C...94.6 °C...95 °C...95.2 °C, etc.), about 105 °C (e.g., 103 °C...103.5 °C...103.8 °C...104.2 °C...104.6 °C...105 °C...105.2 °C, etc.), about 110 °C (e.g., 108 °C...108.5 °C...108.8 °C...109.2 °C...109.6 °C...110 °C...110.2 °C, etc.), about 125 °C (e.g., 123 °C...123.5 °C...123.8 °C...124.2 °C...124.6 °C...125 °C...125.2 °C, etc.), etc.

[0076] In some embodiments, the vapor phase tin can comprise tetrakis(dimethylamino)tin and the vapor phase oxygen can comprise water. It should be appreciated that any other suitable gaseous tin source and gaseous oxygen source for atomic layer deposition can be employed as practically desired.

[0077] The method for making a perovskite solar cell described herein can further comprise the steps of: (i) providing an anode comprising an electrically conductive material; (ii) depositing a perovskite active layer on the anode; (iii) subjecting the perovskite active layer to a surface passivation treatment; and (iv) providing a cathode on the electron transport layer by way of thermal evaporation.

[0078] In some embodiments, the anode can be a transparent conductive substrate, such as a glass on which an electrically conductive material described herein is deposited. In these embodiments, step (i) can begin with cleaning the transparent conductive substrate under sonication with one or more suitable reagents or solvents (e.g., a detergent, deionized water, acetone, isopropyl alcohol, etc.), for example, for about 20 to about 30 minutes each. Thereafter, the cleaned transparent conductive substrate can be optionally dried in an oven, for example, at about 100 °C, followed by an oxygen plasma treatment, for example, for about 10 minutes to about 42 minutes.

[0079] Step (ii) can include the step of providing a precursor solution comprising: x MA y FA 1-x-y Sn z Pb 1- z I 3-m Br mCsI, FAI, MAI, MABr, PbBr2, PbI2, and SnI2, where x is 0-0.5, y is 0-0.5, z is 0-0.5, m is 0-1.5, and a hole transport material; spin coating a precursor solution on the anode; and annealing the spin-coated anode to form a perovskite active layer thereon.

[0080] In some embodiments, perovskite precursor materials (i.e., CsI, FAI, MAI, MABr, PbBr2, PbI2, and SnI2) can be mixed in a suitable solvent or solvent mixture (e.g., a mixture of DMF and DMSO, where the volume ratio is, for example, about 2: 1 to about 15: 1) to obtain a perovskite precursor solution. Thereafter, a hole transport material can be mixed with the perovskite precursor solution, where the concentration of the hole transport material is about 0.15 mg / mL to about 1.2 mg / mL (e.g., about 0.15 mg / mL (e.g., 0.13 mg / mL...0.135 mg / mL...0.14 mg / mL...0.146 mg / mL, 0.15 mg / mL...0.151 mg / mL...0.152 mg / mL...0.16 mg / mL, etc.), about 0.25 mg / mL (e.g., 0.23 mg / mL...0.235 mg / mL...0.24 mg / mL...0.246 mg / mL, 0.25 mg / mL...0.251 mg / mL...0.252 mg / mL...0.26 mg / mL, etc.), about 0.32 mg / mL (e.g., 0.30 mg / mL...0.306 mg / mL...0.31 mg / mL...0.313 mg / mL...0.317 mg / mL...0.32 mg / mL...0.324 mg / mL...0.33 mg / mL, etc.), about 0.5 mg / mL (e.g., 0.46 mg / mL...0.484 mg / mL...0.49 mg / mL...0.493 mg / mL...0.497 mg / mL...0.5 mg / mL...0.504 mg / mL...0.51 mg / mL, etc.), about 0.8 mg / mL (e.g., 0.75 mg / mL...0.764 mg / mL...0.77 mg / mL...0.773 mg / mL...0.797 mg / mL...0.8 mg / mL...0.804 mg / mL...0.81 mg / mL, etc.), about 1.2 mg / mL (e.g., 1.1 mg / mL...1.15 mg / mL...1.18 mg / mL...1.2 mg / mL...1.24 mg / mL...1.26 mg / mL...1.3 mg / mL, etc.), etc.) to form a precursor solution. It is believed that by using the precursor solution described herein, the deposition of perovskite material with hole transport material can be accomplished in one single step. This not only simplifies the fabrication process, but also reduces the production cost, provides greater scalability and industrialization potential.Further, adding a hole-transporting material to the precursor solution can promote uniform growth of perovskite crystals and reduce grain boundary defects during deposition, ultimately improving the stability and optoelectronic performance of the resulting perovskite active layer.

[0081] The precursor solution can then be spin-coated on the anode. Specifically, the precursor solution can be added dropwise to the anode and allowed to sit for, e.g., about 5 seconds to about 30 seconds before starting the spin-coating process. In some embodiments, the spin-coating process can be performed at about 1000 rpm to about 3500 rpm (e.g., 990 rpm... 1000 rpm... 1010 rpm... 1100 rpm... 1500 rpm... 1505 rpm... 3460 rpm... 3490 rpm... 3500 rpm... 3530 rpm, etc.) followed by about 4000 rpm to about 7500 rpm (e.g., 3970 rpm... 3980 rpm... 4000 rpm... 4010 rpm... 4400 rpm... 4950 rpm... 5000 rpm... 5020 rpm... 5470 rpm... 5500 rpm... 7500 rpm... 7530 rpm, etc.). Specifically, chlorobenzene (CB) or ethyl acetate (EA) can be added to the center of the anode about 10 seconds to about 25 seconds before the end of the spin-coating process. The spin-coated anode can then be annealed on a hot plate at, e.g., about 80 °C to about 150 °C (e.g., 77 °C... 80 °C... 84 °C... 96 °C... 100 °C... 101 °C... 105 °C... 117 °C... 120 °C... 123 °C... 125 °C... 146 °C... 150 °C... 153 °C, etc.) for, e.g., about 10 minutes to about 90 minutes to form a perovskite active layer.

[0082] Step (iii) can comprise the steps of spin-coating a surface passivation solution comprising a phenethylamine salt and a perylene diimide-based compound on the perovskite active layer obtained in step (ii); and annealing the spin-coated perovskite active layer to form a passivation layer thereon.

[0083] In some embodiments, the surface passivation solution can be prepared by dissolving a phenethylamine salt described herein in a suitable solvent mixture (e.g., IPA:DMF (v / v = about 50:1 to about 300:1)), for example, with an (initial) concentration of about 0.5 mg / mL to about 4 mg / mL, to form a first solution; dissolving a perylenediimide-based compound described herein in a suitable solvent mixture (e.g., IPA:DMF (v / v = about 50:1 to about 300:1)), for example, with an (initial) concentration of about 0.5 mg / mL to about 8 mg / mL), to form a second solution; mixing the first solution and the second solution at a volume ratio of about 1:1 to form the surface passivation solution.

[0084] The surface passivation solution can then be spin-coated on the perovskite active layer at about 4000 rpm to about 6000 rpm (e.g., 3910 rpm... 3950 rpm... 3980 rpm... 4000 rpm... 4030 rpm... 4600 rpm... 4850 rpm... 5000 rpm... 5240 rpm... 5580 rpm... 6000 rpm... 6080 rpm, etc.), for example, for about 20 to about 40 seconds. Thereafter, the spin-coated perovskite active layer can be annealed on a hotplate at about 75 °C to about 120 °C (e.g., 73.5 °C... 74.4 °C... 74.8 °C... 75 °C... 75.8 °C... 97.5 °C... 99.1 °C... 100 °C... 108 °C... 108.7 °C... 110 °C... 110.6 °C... 111 °C... 118.2 °C... 119 °C... 120 °C... 120.9 °C... 121 °C, etc.) for about 1 minute to about 15 minutes, for example, to form the passivation layer.

[0085] In step (iv), the cathode can be formed by depositing a cathode material on top of the second portion of the electron transport layer at a reduced pressure (e.g., less than 4 x 10 -6about 0.2 A / s to about 3 A / s (e.g., 0.17 A / s...0.19 A / s...0.2 A / s...0.21 A / s...0.23 A / s...0.78 A / s...0.8 A / s...0.94 A / s...1 A / s...1.05 A / s...1.1 A / s...1.7 A / s...1.88 A / s...2 A / s...2.09 A / s...2.82 A / s...3 A / s...3.06 A / s...3.1 A / s, etc.) to provide a thickness of about 50 nm to about 250 nm (e.g., 48.5 nm...49 nm..49.4 nm...49.8 nm...50 nm...50.3 nm...51 nm...73.8 nm...74.5 nm...75 nm...75.7 nm...76 nm...98 nm...98.8 nm...99.1 nm...100 nm...100.2 nm...101 nm...149 nm...149.6 nm...150 nm...150.7 nm...151 nm...248 nm...248.9 nm...249.6 nm...250 nm...250.2 nm...252 nm, etc.).

[0086] Hereinafter, the present application is described more specifically by way of examples, but the present application is not limited thereto.

[0087] Examples Materials and Methods Materials Trifluoromethylphenethylammonium iodide (CF3-PEAI) was purchased from Lumtec (Taiwan Luminescence Technology) and Dyenamo (Sweden). Perylenediimide derivatives (PDIN) and naphthalene diimide derivatives (NDI-N) were purchased from Sigma-Aldrich and TCI (Tokyo Chemical Industry). Tin (II) iodide (SnI2) was purchased from Alfa Aesar, Sigma-Aldrich, and Strem Chemicals. Carbazole phosphonic acid (2PACz) was purchased from Lumtec and Merck. Methoxy-substituted 2PACz (MeO-2PACz) was purchased from Lumtec and TCI. Fluorine-doped tin oxide conductive glass (FTO) and niobium-doped titanium oxide (NTO) were purchased from NSG Group (Nippon Sheet Glass, Japan) and Xoptica (AGC, China). Methylammonium bromide (MABr) was purchased from TCI and Greatcell Solar Materials (Australia). Bromo-substituted 2PACz (Br-2PACz) and tetraphenyl-dibromo-carbazole derivative (4PADBC) were purchased from Lumtec. Methoxyphenyl ethyl ammonium iodide (CH3O-PEAI) and tetrafluorophenyl ethyl ammonium iodide (4F-PEAI) were purchased from Xi'an Polymer Light Technology (China) and Dyenamo (Sweden). Perylenediimide N-oxide (PDINO) was purchased from Sigma-Aldrich and 1-Material (Canada). Aluminum-doped zinc oxide (AZO) was purchased from AGC (Asahi Glass, Japan) and Umicore (Belgium). Carbazole-based compounds (CbzBF / CbzBT) were purchased from Lumtec and Ossila (UK). Ethyl acetate (EA) was purchased from Fisher Chemical, Sinopharm Group (China). Gallium-doped zinc oxide (GZO) was purchased from Mitsubishi Materials (Japan). Phenyl ethyl ammonium chloride (PEACI) was purchased from TCI and Aladdin Reagent (China). Phenyl ethyl ammonium iodide (PEAI) was purchased from Greatcell Solar Materials, Xi'an Polymer Light Technology.

[0088] Formamidinium iodide (FAI) and cesium iodide (Csl) were purchased from Dysol (Australia). Lead iodide (Pbl2), lead bromide (PbBr2) and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) were purchased from TCI (Japan). Fatty amine functionalized perylene diimide (PDINN) was purchased from Beijing Organtec Co., Ltd (China). C60, bathocuproine (BCP), 3-fluorophenethylammonium iodide (mF-PEAI), methylammonium chloride (MACl) and propylammonium chloride (PACl) were purchased from Xi’an Polymer Light Technology Corporation (China). Tetra(dimethylamino)tin (TDMASn) was purchased from Shanghai Oriphant Chemistry Co., Ltd (China). Solvents including dimethylformamide (DMF), dimethyl sulfoxide (DMSO), isopropyl alcohol (IPA) and chlorobenzene (CB) were purchased from J&K (China) and used as received. High purity silver and gold were purchased from commercial sources. 1.1 mm glass substrates with indium tin oxide (ITO) (15 Ω sq -1 ) pattern were purchased from Mishi Tech. Co., Ltd. (China).

[0089] Characterization X-ray photoelectron spectroscopy (XPS) measurements were performed by an AXIS Supra XPS system. The system was equipped with a monochromatic Al Kα X-ray source (1486.6 eV). The base pressure during the measurements was kept at about 10 -9 millibar. Survey scans were performed to identify the elemental composition, while high-resolution scans were used to analyze the chemical states of specific elements. The binding energies were calibrated using the C 1s peak at 284.8 eV as a reference.

[0090] Steady-state photoluminescence (PL) spectra were obtained by an Edinburgh FLS980 with an excitation wavelength of 375 nm. The system was equipped with a photomultiplier tube (PMT) detector for steady-state measurements and a time-correlated single-photon counting (TCSPC) module for time-resolved measurements. The emission spectra were recorded in the range of 600-900 nm with a step size of 1 nm.

[0091] The film thicknesses of SnO x and SnO x(i) were obtained by a Dektak XT stylus profilometer. The sample preparation included the adhesion of a tape to half of the substrate, and the deposition of SnO xThe deposited material is then removed. This process creates thickness steps in the areas with and without the tape, allowing for the measurement of SnO. x Deposition thickness. The probe scanning distance was set to 1000 μm to ensure that the probe could penetrate the thickness steps.

[0092] The ultraviolet-vis (UV-vis) absorption of the film was recorded using a UV-vis spectrometer (Perkin Elmer Lambda 2S system). Measurements were performed in the wavelength range of 300–900 nm with 1 nm steps. The system was equipped with a dual-beam optics configuration to ensure high stability and accuracy. Baseline correction was performed using a reference sample to eliminate any background noise. The scan rate was set to 240 nm / min.

[0093] Ultraviolet photoelectron spectroscopy (UPS) was performed in a Thermo ESCALAB 250XI equipped with a helium discharge lamp (hv ​​= 21.22 eV). The chamber was evacuated to approximately 10 eV. -9 A basic pressure of millibars was used to ensure minimal contamination during the measurement process. A clean Au sample was used to calibrate the analyzer to ensure accurate energy measurements. The binding energy range of the UPS spectrometer was 0 to 25 eV in 0.05 eV steps. The work function of the sample was determined by measuring the secondary electron cutoff, while the valence band structure was analyzed starting from photoemission.

[0094] Used at 900 to 1800 cm -1 Peak force infrared (PFIR) measurements were performed using a commercially available Bruker NanoIR2-FS unit operating within the test range. This unit integrates an atomic force microscope (AFM) operating in contact mode, enabling high-resolution topographic and chemical mapping of the sample surface. Furthermore, Fourier transform infrared (FTIR) spectroscopy analysis was performed using a Bruker Tensor 27 spectrometer from Germany. This technique involves collecting PDINN molecules at 1650 cm⁻¹. -1 The infrared spectrum of the intensity and distribution of the C=O stretching vibration at the location.

[0095] According to previously reported methods, in a configuration of ITO / SnO2 (spin-coated) / active layer / passivation layer / SnO x(i) (ALD) / SnO x Space charge-limited current (SCLC) was measured on a single-electron device with an (ALD) / Ag configuration. SCLC measurements were recorded in dark conditions from 0 to 3 V in 0.02 V steps using a Keithley 2400 source / instrumentation unit. J-V feature.

[0096] Time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements were performed using a TOF-SIMS instrument (IonTof M6, Germany). The primary ions used for analysis were Bi 3+ with an energy of 30 keV and a current of 0.80 pA. The primary ion dose (PID) was 4.09E+12 ions / cm 2 . For sputtering, O 2+ ions were used with an energy of 1 keV and a current of 400 nA. The sputtering area was 400 x 400 pm 2 and the sputtering ion dose density (SpIDD) was 2.11E+18 ions / cm 2 . The intensities of the detected ions were recorded in arbitrary units (a.u.) over the sputtering time, which was in seconds. The analysis included various ions, such as Sn + , Pb + , I + , CH5N2 + , In + , InO + , Ag + , and Br + , and their intensities were plotted against the sputtering time to gain insight into the composition and distribution of elements within the surface layer of the sample.

[0097] The photovoltaic performance characteristics (J-V curves) of perovskite solar cells were performed at room temperature using a xenon lamp solar simulator (Enlitech, SS-F5, Taiwan) in a N2-filled glovebox. J-V The light power was calibrated to 100 mW cm -2 using a silicon reference cell with a KG2 filter. Prior to performing J-V measurements, a 125 nm layer of magnesium fluoride was deposited on the back side of the ITO substrate to enhance the transmittance. All device measurements were performed using a Keithley 2400 source meter with a scan mode of reverse scan (1.20 V to -0.01 V) and forward scan (-0.01 V to 1.20 V) at a scan rate of 0.01 V s -1 with a delay time of 10 ms. No pre-conditions were required prior to measurements. The active area was defined and characterized as 0.0510 cm 2 by metal shadow masking. The stable current density output at the MPP bias was monitored (from the reverse scan J-VStable power output is achieved by extracting from the curve. External quantum efficiency (EQE) is measured using a QE-R EQE system (Enlitech, Taiwan). High-sensitivity EQE is measured using an integrated system (PECT-600, Enlitech, Taiwan), where the photocurrent is amplified and regulated by a locked instrument. Electroluminescence (EL) quantum efficiency (EQEEL) is measured by applying an external voltage / current source using an instrument (ELCT-3010, Enlitech, Taiwan).

[0098] Stability test Damp heat stability testing: The device was subjected to damp heat testing by placing it in an environmental test chamber at 85°C / 85% RH. After cooling to room temperature, the device was removed and... J-V Measurement.

[0099] Outdoor stability testing: For devices tested outdoors, the devices are periodically brought back indoors and measured in air under simulated AM1.5G sunlight.

[0100] Light-on-off cycle test: The LED lights were subjected to a simulated AM1.5G day and night cycle test of one sun for 42 cycles over a period of approximately 1008 hours (12 hours on, 12 hours off cycle).

[0101] Long-term operational stability testing: The device was operated in an air environment (22±3℃, 46±8%RH) under the equivalent of one sun LED. The PSC was biased at the maximum power point (MPP) voltage, and the power output was tracked using a multi-regulator (CHI1040C, CHInstruments, Inc.). During the MPP test, the device's current density-voltage ratio was acquired every 12 hours. J-V The appropriate load for the MPP was determined by calculating the curve. To test at 65°C, the device was mounted on a heating plate. The device temperature was monitored periodically with a thermometer.

[0102] Thermal cycling test: The device was placed in a thermal cycling test chamber (Shenzhen Hongruida Environmental Technology Co., Ltd.) and subjected to temperature cycling from -40°C (5 minutes) to 85°C (5 minutes) at a rate of 200°C / hour. After 50, 100, 200, 400, 600, and 800 cycles, the device was removed from the chamber and subjected to further testing. J-V Measurement.

[0103] Devices that required encapsulation were sealed using a UV encapsulation adhesive (LT-U001, Luminescent Technology Corp.) and covered with glass (0.7 mm).

[0104] Density functional theory (DFT) calculations First-principles density functional theory (DFT) calculations were performed using the Vienna Ab Initio Simulation Package (VASP 6.4) to investigate pristine and defect-induced FAPbI3 / SnO 2±x Geometrical and electronic structures of heterostructures. Projector augmented wave (PAW) pseudopotentials with a cutoff energy of 600 eV were used. The generalized gradient approximation (GGA) exchange-correlation function Perdew-Burke-Ernzerhof (PBE) and DFT-D3 dispersion correction method of Grimme with zero damping were used to optimize the geometrical structures. During the geometry optimization, all structures were relaxed until each atom reached mechanical equilibrium with a residual force of no more than 10 -4 eV / Å. For all heterojunction systems, we used a 20-angstrom vacuum slab to isolate the structures in the stacking direction. For all calculations of pristine surfaces and defect-induced surfaces, we used the PBE theoretical level and a 4x4x1 Monkhost-Pack k-point grid centered at Gamma. For strong relativistic effects of Pb-based perovskite structures, the spin-orbit coupling (SOC) effect was considered.

[0105] The electronic orbital composition was 1s for H, 2s2p for CN and O, 4d5p for Sn and I, and Sd6p for Pb. The defect formation energy (DFE) was considered to be DFE = E def – (E 原始 +∑ε i ) + q(E f + VBM + V corr ), where E def represents the defect-induced structure, E 原始 represents the pristine reference structure, ∑ε i means the total energy of defect-induced interaction. The last three terms are charge-dependent corrections, which are the Fermi level, the valence band maximum, and the potential correction, respectively. Since the VASP 6.4 package cannot accurately handle charged heterostructures within a vacuum layer, all defects were considered to be neutral charge (q = 0), and the charge-dependent corrections were negated.

[0106] Since SnO xThere is a clear lattice mismatch between the crystal, the PDINN layer and the perovskite framework, so additional DFT calculations using a larger supercell were also considered, for which the data analysis was based only on the PBE+SOC theoretical level. Due to the very large PDINN molecular geometry (with a maximum intra-molecular distance of 52 angstroms), a very large supercell and a very strong lattice mismatch can occur, so only one amino side chain was retained instead of the two originally designed, while the other side was methylated.

[0107] In particular, the combined perovskite-SnO x The interface system consists of 4 layers of SnO x and 3 layers of perovskite framework, with a 20 angstrom vacuum layer added on top of the heterostructure. The PDINN-containing structure was double-optimized by sandwiching the PDINN molecule. To perform the geometry optimization, the central metal atoms in the two terminal layers adjacent to the vacuum plate were fixed, and these cores would be excluded from the electronic property calculation of the heterostructure system. Therefore, the least common multiple supercell crystal exhibits a <1% planar mismatch.

[0108] Example 1 PSC 1 (FTO / Cs 0.05 MA 0.5 FA 0.45 Sn 0.2 Pb 0.8 I3: MeO-2PACz / CF3-PEAI: PDIN / SnO x(i) / SnO x / Au) fabrication 1. Substrate treatment: The patterned fluorine-doped tin oxide (FTO) conductive substrate was sequentially cleaned with detergent, deionized water, acetone and isopropanol for 20 minutes each time. After drying the cleaned substrate in an oven at 100°C, the substrate surface was treated with oxygen plasma for 40 minutes and transferred to a N2-filled glovebox before use.

[0109] 2. Preparation of perovskite solution: CsI, FAI, MAI, PbI2 and SnI2 were added together to a DMF:DMSO (volume ratio 3:1) mixed solvent according to the chemical formula Cs 0.05 MA 0.5 FA 0.45 Sn 0.2 Pb 0.8 I3 to prepare a perovskite precursor solution. After 1 h of thorough stirring, MeO-2PACz was added to the perovskite precursor solution, with a final concentration of 0.15 mg / ml in the perovskite precursor solution. After thorough mixing, the perovskite solution was formed.

[0110] 3. Perovskite film preparation: The perovskite solution (100 μΐ^) obtained from step (2) was dropped onto the transparent conductive substrate obtained from step (1) and allowed to stand for 10 seconds. It was then spin-coated at 2000 rpm for 15 seconds, followed by 6000 rpm for 90 seconds. At 15 seconds before the end of the last spin-coating, chlorobenzene (CB) (300 μΐ^) was dropped onto the center of the film. The spin-coated perovskite film was then annealed on a hot plate at 150 °C for 10 minutes.

[0111] 4. Surface passivation treatment: CF3-PEAI (concentration of 2 mg / ml) and PDIN (concentration of 6 mg / ml) were separately dissolved in a mixed solvent of IPA:DMF (volume ratio of 300:1). The two solutions were then mixed at a volume ratio of 1:1 and spin-coated onto the perovskite film prepared in step (3) with a spin-coating condition of 6000 rpm for 20 seconds, followed by annealing at 120 °C for 10 minutes.

[0112] 5. SnO x Deposition of electron transport layer: On the surface passivated perovskite film obtained in step (4), SnO x and SnO x(i) layers were sequentially deposited by atomic layer deposition (ALD) from TDMASn and water at 95 °C. For the SnO x(i) intermediate layer, the pulse time of TDMASn:H2O was 120 ms:10 ms with a deposition thickness of 5 nm. For the SnO x transport layer, the pulse time of TDMASn:H2O was 100 ms:40 ms with a deposition thickness of 25 nm.

[0113] 6. Electrode deposition: A 150 nm gold was thermally evaporated at a rate of 2 Å / s under high vacuum (<4 × 10 -6 Torr) to form the top electrode of the perovskite solar cell.

[0114] Example 2A Fabrication of PSC 2A (ITO / Cs 0.05 FA 0.95 PbI 2.94 Br 0.06 : Me-4PACz / m-F-PEAI: PDINN / SnO x(i) / SnO x / Ag) 1. Substrate treatment: The patterned indium tin oxide (ITO) conductive substrate is ultrasonically cleaned sequentially with detergent, deionized water, acetone, and isopropanol, each cleaning lasting 30 minutes. After drying the cleaned substrate in an oven at 100°C, the substrate surface is treated with oxygen plasma for 20 minutes and then transferred to a glove box filled with N2 before use.

[0115] 2. Preparation of perovskite solution: CsI, FAI, PbBr2, and PbI2 are prepared according to the chemical formula Cs 0.05 FA 0.95 PbI 2.94 Br 0.06 Together, they were added to a DMF:DMSO (volume ratio 5:1) mixed solvent to prepare a perovskite precursor solution. After stirring thoroughly for 1 h, Me-4PACz was added to the perovskite precursor solution, with a final concentration of 0.32 mg / ml. After thorough mixing, a perovskite solution was formed.

[0116] 3. Preparation of perovskite thin film: The perovskite solution obtained in step (2) was dropped onto the transparent conductive substrate obtained in step (1) and allowed to stand for 30 seconds. Then, it was spin-coated at 1500 rpm for 5 seconds, followed by spin-coating at 5500 rpm for 45 seconds. 15 seconds before the end of the final spin-coating, chlorobenzene (CB) was dropped onto the center of the film. The spin-coated perovskite thin film was then annealed on a hot plate at 100°C for 40 minutes.

[0117] 4. Surface passivation treatment: mF-PEAI (concentration of 2 mg / ml) and PDINN (concentration of 2 mg / ml) were separately dissolved in an IPA:DMF (volume ratio of 150:1) mixed solvent. The two solutions were then mixed at a volume ratio of 1:1 and spin-coated onto the perovskite film prepared in step (3) under the following conditions: spin-coating at 5000 rpm for 30 seconds, followed by annealing at 100°C for 30 minutes.

[0118] In any case, if PDINN precipitates from the solution, or if the PDINN film aggregates (under an optical microscope), trifluoroethanol can be used instead of IPA to increase solubility. The spin coating process is carried out in a glove box filled with N2, where the temperature is controlled at 19–24°C by integrated air conditioning, and the levels of water and oxygen should be controlled below 5 ppm.

[0119] 5. SnO x Electron transport layer deposition: On the surface-passivated perovskite film obtained in step (4), SnO was deposited by atomic layer deposition (ALD) of TDMASn and water at 95°C. x and SnO x(i) Layer. For SnOx(i) Deposition of the intermediate layer, with a pulse time of 200 ms:20 ms for TDMASn:H2O, where the deposition thickness was 3 nm. For SnO x Deposition of the transport layer, with a pulse time of 50 ms:20 ms for TDMASn:H2O, where the deposition thickness was 35 nm.

[0120] 6. Electrode deposition: 100 nm of silver was thermally evaporated at a rate of 1 Å / s under high vacuum (<4 × 10 -6 Torr) to form the top electrode of the perovskite solar cell.

[0121] Example 2B PSC 2B (ITO / Cs 0.05 FA 0.95 PbI 2.94 Br 0.06 : Me-4PACz / m-F-PEAI:PDINN / SnO x(i) / SnO x / Ag or Au) This example is a slight modification of Example 2A.

[0122] 1. Substrate treatment: A glass / ITO substrate (15 Ω sq-1) was sequentially cleaned with detergent, deionized water, acetone, and isopropanol for 20 minutes each using ultrasonic cleaning. The glass / ITO substrate was then dried in an oven at 100 °C, followed by oxygen plasma treatment for 15 min and transferred into a N2-filled glovebox before use.

[0123] 2. Perovskite solution preparation: A perovskite solution (1.55 M) was prepared by mixing CsI, FAI, PbI2, and PbBr2 according to the chemical formula Cs 0.05 FA 0.95 PbI 2.94 Br 0.06 in 1 ml of DMF:DMSO (5:1 by volume) mixed solvent. Optionally, 10 mol% excess of PbI2was added to improve device performance, and optionally 10.5 mol% MACI and 3.2 mol% PACI were added to the perovskite precursor solution and stirred for 1 h. Me-4PACz was then added to the perovskite precursor at a concentration of 0.32 mg / ml, followed by shaking for 30 seconds to form the perovskite solution.

[0124] 3. Perovskite film preparation: 100 μΐ^of perovskite solution was dropped onto the ITO substrate, left undisturbed for 15 seconds, then spin-coated at 1000 rpm for 10 s, followed by 5000 rpm for 40 s. 10 s before the end of the spin-coating, 300 μΐ^of CB was dropped onto the center of the film. The deposited perovskite film was then annealed on a hotplate at 100 °C for 35 min.

[0125] 4. Surface passivation treatment: m-F-PEAI (2 mg / ml concentration) and PDINN (2 mg / ml concentration) were separately dissolved in a mixed solvent of IPA:DMF (200:1 by volume) and stirred for 1 h. The two solutions were then mixed at a volume ratio of 1:1 and dynamically rotated at 5000 rpm for 30 s on the prepared perovskite film, followed by annealing at 100 °C for 10 min.

[0126] In any case, if PDINN precipitates out of solution, or if the PDINN film appears to aggregate (under optical microscope), trifluoroethanol can be used instead of IPA to increase solubility. The spin-coating process was carried out in a N2-filled glovebox, where the temperature was controlled by integrated air conditioning to be 19-24 °C, and the water and oxygen levels should be controlled to be below 5 ppm.

[0127] 5. SnO x Deposition of electron transport layer: SnO x and SnO x(i) layers were deposited by atomic layer deposition (ALD) from TDMASn and water at 105 °C. The TDMASn precursor was heated to 60 °C, and the water source was unheated. The nitrogen chamber and process flow rates were set to 200 and 30 seem, respectively. The TDMASn was dosed according to a charge-pulse program consisting of 0.3 s nitrogen charge and 0.5 s pulse. a) For SnO x(i) intermediate layer, the tin oxide growth consisted of a process of 30 cycles of: TDMASn dose (200 ms), purge (6 s for the first 10 cycles, 13 s for cycles 10-20, and 20 s for the last 10 cycles), water dose (20 ms), and purge (20 s). b) For SnO x transport layer, the tin oxide growth consisted of a process of 300 cycles of: TDMASn dose (50 ms), purge (10 s), water dose (20 ms), and purge (20 s).

[0128] 6. Electrode deposition: 100 nm silver or gold electrodes were thermally evaporated at a rate of 1.0 Å / s under high vacuum (<4 × 10 -6 torr).

[0129] Example 3 PSC 3 (NTO / MA 0.5 FA 0.5 Sn 0.5 Pb 0.5 I 2.25 Br 0.75 : Br-2PACz / CH3O-PEAI: PDINO / SnO x(i) / SnO x / Cu) of Example 3 1. Substrate treatment: The patterned niobium-doped titanium dioxide (NTO) conductive substrate was sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 25 minutes each time. After drying the cleaned substrate in an oven at 100 °C, the substrate surface was treated with oxygen plasma for 10 minutes and transferred into a N2-filled glovebox before use.

[0130] 2. Preparation of perovskite solution: CsI, FAI, MAI, MABr, PbBr2, PbI2and SnI2were added together into DMF:DMSO (volume ratio of 15:1) mixed solvent to prepare a perovskite precursor solution. After 1 h of thorough stirring, Br-2PACz was added into the perovskite precursor solution with a final concentration of 1.2 mg / ml in the perovskite precursor solution. After thorough mixing, the perovskite solution was formed. 0.5 FA 0.5 Sn 0.5 Pb 0.5 I 2.25 Br 0.75 3. Preparation of perovskite thin film: The perovskite solution (100 μΐ^) obtained from step (2) was dropped onto the transparent conductive substrate obtained from step (1) and allowed to stand for 5 seconds. It was then spin-coated at 3500 rpm for 5 seconds, followed by spin-coating at 7500 rpm for 40 seconds. At 10 seconds before the end of the last spin-coating, chlorobenzene (CB) (300 μΐ^) was dropped onto the center of the film. The spin-coated perovskite thin film was then annealed on a hot plate at 125 °C for 20 minutes.

[0131] 4. Surface passivation treatment: CH3O-PEAI (concentration of 0.5 mg / ml) and PDINO (concentration of 0.5 mg / ml) were separately dissolved in IPA:DMF (volume ratio of 50:1) mixed solvent. The two solutions were then mixed in a volume ratio of 1:1 and spin-coated onto the perovskite thin film prepared in step (3) with spin-coating conditions of 6000 rpm for 20 seconds, followed by annealing at 75 °C for 15 minutes.

[0132] 4. Surface passivation treatment: CH3O-PEAI (concentration of 0.5 mg / ml) and PDINO (concentration of 0.5 mg / ml) were separately dissolved in IPA:DMF (volume ratio of 50:1) mixed solvent. The two solutions were then mixed in a volume ratio of 1:1 and spin-coated onto the perovskite thin film prepared in step (3) with spin-coating conditions of 6000 rpm for 20 seconds, followed by annealing at 75 °C for 15 minutes.

[0133] 5. Deposition of SnOx electron transport layer: On the surface passivated perovskite thin film obtained in step (4), SnO x and SnO x(i) layers were sequentially deposited by atomic layer deposition (ALD) from TDMASn and water at 85 °C. For the deposition of SnO x(i) intermediate layer, the pulse time of TDMASn:H2O was 400 ms:10 ms, with a deposition thickness of 5 nm. For the deposition of SnO x transport layer, the pulse time of TDMASn:H2O was 20 ms:10 ms, with a deposition thickness of 50 nm.

[0134] 6. Electrode deposition: 75 nm of copper was thermally evaporated at a rate of 0.2 Å / s under high vacuum (<4 × 10 -6 Torr) to form the top electrode of the perovskite solar cell.

[0135] Example 4 Fabrication of PSC 4 (AZO / Cs 0.3 FA 0.7 PbI 2.4 Br 0.6 : CbzBF / 4F-PEAI: NDI-N / SnO x(i) / SnO x / Ni) 1. Substrate treatment: A patterned aluminum-doped zinc oxide (AZO) conductive substrate was sequentially cleaned with a detergent, deionized water, acetone, and isopropanol for 30 minutes each using ultrasonic cleaning. After drying the cleaned substrate in an oven, the substrate surface was treated with oxygen plasma for 30 minutes and transferred into a N2-filled glovebox before use.

[0136] 2. Perovskite solution preparation: CsI, FAI, PbBr2, and PbI2 were added together into a mixed solvent of DMF:DMSO (volume ratio of 9:1) to prepare a perovskite precursor solution according to the chemical formula Cs 0.3 FA 0.7 PbI 2.4 Br 0.6 After 1 h of thorough stirring, CbzBF was added into the perovskite precursor solution, with a final concentration of 0.8 mg / ml in the perovskite precursor solution. After thorough mixing, the perovskite solution was formed.

[0137] 3. Perovskite film preparation: The perovskite solution obtained from step (2) (100 μL) was dropped onto the transparent conductive substrate obtained from step (1) and allowed to stand for 20 seconds. It was then spin-coated at 1000 rpm for 10 seconds, followed by 4000 rpm for 30 seconds. Ethyl acetate (EA) was dropped onto the center of the film 15 seconds before the end of the last spin-coating. The spin-coated perovskite film was then annealed on a hot plate at 80 °C for 90 minutes.

[0138] 4. Surface passivation treatment: 4F-PEAI (concentration of 4 mg / ml) and NDI-N (concentration of 8 mg / ml) were separately dissolved in a mixed solvent of IPA:DMF (volume ratio of 250:1). The two solutions were then mixed at a volume ratio of 1:1 and spin-coated onto the perovskite film prepared in step (3) under the spin-coating condition of 4000 rpm for 40 seconds, followed by annealing at 110 °C for 1 minute.

[0139] 5. SnO x Deposition of electron transport layer: On the surface-passivated perovskite film obtained in step (4), SnO x and SnO x(i) layers were sequentially deposited by atomic layer deposition (ALD) from TDMASn and water at 125 °C. For the SnO x(i) intermediate layer, the pulse time of TDMASn:H2O was 180 ms:5 ms, with a deposition thickness of 10 nm. For the SnO x transport layer, the pulse time of TDMASn:H2O was 50 ms:30 ms, with a deposition thickness of 15 nm.

[0140] 6. Electrode deposition: 250 nm of nickel was thermally evaporated at a rate of 3 Å / s under high vacuum (<4 × 10 -6 Torr) to form the top electrode of the perovskite solar cell.

[0141] Example 5 Fabrication of PSC 5 (GZO / Cs 0.5 FA 0.5 Sn 0.5 Pb 0.5 I 1.5 Br 1.5 : CbzBT / PEACl: PDINN / SnO x(i) / SnO x / Al) 1. Substrate treatment: The patterned gallium-doped zinc oxide (GZO) conductive substrate was ultrasonically cleaned sequentially with detergent, deionized water, acetone, and isopropanol, each cleaning session lasting 20 minutes. After drying the cleaned substrate in an oven, the substrate surface was treated with oxygen plasma for 15 minutes and then transferred to a glove box filled with N2 before use.

[0142] 2. Preparation of perovskite solution: CsI, FAI, PbBr2, PbI2, and SnI2 are prepared according to the chemical formula Cs 0.5 FA 0.5 Sn 0.5 Pb 0.5 I 1.5 Br 1.5 Together, they were added to a DMF:DMSO (volume ratio 2:1) mixed solvent to prepare a perovskite precursor solution. After stirring thoroughly for 1 h, CbzBT was added to the perovskite precursor solution, with a final concentration of 0.5 mg / ml. After thorough mixing, a perovskite solution was formed.

[0143] 3. Preparation of perovskite thin film: The perovskite solution obtained in step (2) was dropped onto the transparent conductive substrate obtained in step (1) and allowed to stand for 10 seconds. Then, it was spin-coated at 1500 rpm for 10 seconds, followed by spin-coating at 5000 rpm for 50 seconds. Ethyl acetate (EA) was dropped onto the center of the film 25 seconds before the end of the final spin-coating. The spin-coated perovskite film was then annealed on a hot plate at 100°C for 50 minutes.

[0144] 4. Surface passivation treatment: PEACl (concentration of 2 mg / ml) and PDINN (concentration of 3 mg / ml) were separately dissolved in an IPA:DMF (volume ratio of 200:1) mixed solvent. The two solutions were then mixed at a volume ratio of 1:1 and spin-coated onto the perovskite film prepared in step (3) under the following conditions: spin-coating at 5000 rpm for 30 seconds, followed by annealing at 100°C for 5 minutes.

[0145] In any case, if PDINN precipitates from the solution, or if the PDINN film aggregates (under an optical microscope), trifluoroethanol can be used instead of IPA to increase solubility. The spin coating process is carried out in a glove box filled with N2, where the temperature is controlled at 19–24°C by integrated air conditioning, and the levels of water and oxygen should be controlled below 5 ppm.

[0146] 5. SnO x Electron transport layer deposition: On the surface-passivated perovskite film obtained in step (4), SnO was deposited by atomic layer deposition (ALD) of TDMASn and water at 105 °C. xand SnO x(i) layer. For SnO x(i) deposition of the intermediate layer, the pulse time of TDMASn:H20 was 300 ms:20 ms, with a deposition thickness of 2 nm. For SnO x deposition of the transport layer, the pulse time of TDMASn:H20 was 100 ms:20 ms, with a deposition thickness of 30 nm.

[0147] 6. Electrode deposition: 50 nm of aluminum was thermally evaporated at a rate of 1 Å / s under high vacuum (<4 x 10 -6 Torr) to form the top electrode of the perovskite solar cell.

[0148] Example 6 Fabrication of PSC 6 (ITO / FAPbI3:4PADBC / PEAI:PDINN / SnO x(i) / SnO x / Ag) 1. Substrate treatment: A patterned indium tin oxide (ITO) conductive substrate was sequentially cleaned with a detergent, deionized water, acetone, and isopropanol for 30 minutes each using ultrasonic cleaning. After drying the cleaned substrate in an oven, the surface of the substrate was treated with oxygen plasma for 45 minutes and transferred to a N2-filled glovebox before use.

[0149] 2. Perovskite solution preparation: FAI and PbI2 were added together according to the chemical formula FAPbI3 into a mixed solvent of DMF:DMSO (volume ratio of 4:1) to prepare a perovskite precursor solution. After thorough stirring for 1 h, 4PADBC was added to the perovskite precursor solution, with a final concentration of 0.25 mg / ml in the perovskite precursor solution. After thorough mixing, the perovskite solution was formed.

[0150] 3. Perovskite thin film preparation: The perovskite solution obtained in step (2) was dropped onto the transparent conductive substrate obtained in step (1) and allowed to stand for 15 seconds. It was then spin-coated at 1000 rpm for 10 seconds, followed by spin-coating at 5000 rpm for 40 seconds. Ethyl acetate (EA) was dropped onto the center of the film 20 seconds before the end of the last spin-coating. The spin-coated perovskite thin film was then annealed on a hot plate at 120°C for 40 minutes.

[0151] 4. Surface passivation treatment: PEAI (1 mg / ml) and PDINN (4 mg / ml) were separately dissolved in a mixed solvent of IPA:DMF (100:1 by volume). Then the two solutions were mixed in a volume ratio of 1:1 and spin-coated onto the perovskite film prepared in step (3) at 5000 rpm for 30 seconds, followed by annealing at 120 °C for 5 minutes.

[0152] In any case, if PDINN precipitates out of solution, or if PDINN films appear to aggregate (under optical microscopy), trifluoroethanol can be used instead of IPA to increase solubility. The spin-coating process was carried out in a N2-filled glovebox, where the temperature was controlled by integrated air conditioning to be 19-24 °C, and the water and oxygen levels should be controlled to be below 5 ppm.

[0153] 5. SnO x Deposition of electron transport layer: On the surface-passivated perovskite film obtained in step (4), SnO x and SnO x(i) layers were deposited by atomic layer deposition (ALD) from TDMASn and water at 110 °C. x(i) For the deposition of the SnO x intermediate layer, the pulse times of TDMASn:H2O were 200 ms:20 ms, with a deposition thickness of 2 nm. For the deposition of the SnO x transport layer, the pulse times of TDMASn:H2O were 50 ms:20 ms, with a deposition thickness of 40 nm.

[0154] 6. Electrode deposition: 150 nm of silver was thermally evaporated at a rate of 1 Å / s under high vacuum (<4 × 10 -6 Torr) to form the top electrode of the perovskite solar cell.

[0155] Example 7 Comparative PSC 7 (ITO / Cs 0.05 FA 0.95 PbI 2.94 Br 0.06 :Me-4PACz / m-F-PEAI: PDINN / C60 / BCP / Ag or Au) fabrication 1. Substrate treatment: A patterned indium tin oxide (ITO) conductive substrate was ultrasonically cleaned with detergent, deionized water, acetone, and isopropanol for 30 minutes each. After drying the cleaned substrate in an oven, the substrate surface was treated with oxygen plasma for 20 minutes and transferred to a N2-filled glovebox before use.

[0156] 2. Preparation of perovskite solution: Csl, FAI, PbBr and Pbl2 were added together into DMF:DMSO (5:1 by volume) mixed solvent to prepare perovskite precursor solution. After 1 h of thorough stirring, Me-4PACz was added into the perovskite precursor solution with a final concentration of 0.32 mg / ml. After thorough mixing, perovskite solution was formed. 0.05 FA 0.95 Pbl 2.94 Br 0.06

[0157] 3. Preparation of perovskite thin film: The perovskite solution obtained from step (2) was dropped onto the transparent conductive substrate obtained from step (1) and allowed to stand for 30 seconds. It was then spin-coated at 1500 rpm for 5 seconds, followed by spin-coating at 5500 rpm for 45 seconds. Chlorobenzene (CB) was dropped onto the center of the film 15 seconds before the end of the last spin-coating. The spin-coated perovskite thin film was then annealed on a hot plate at 100 °C for 40 minutes.

[0158] 4. Surface passivation treatment: m-F-PEAI (2 mg / ml) and PDINN (2 mg / ml) were separately dissolved in IPA:DMF (150:1 by volume) mixed solvent. The two solutions were then mixed at a volume ratio of 1:1 and spin-coated onto the perovskite thin film prepared in step (3) with a spin-coating condition of 5000 rpm for 30 seconds, followed by annealing at 100 °C for 30 minutes.

[0159] In any case, if PDINN precipitates out of solution, or if the PDINN film appears to aggregate (under optical microscope), trifluoroethanol can be used instead of IPA to increase solubility. The spin-coating process was carried out in a N2-filled glovebox, where the temperature was controlled by integrated air conditioning at 19-24 °C, and the water and oxygen levels should be controlled below 5 ppm.

[0160] 5. Deposition of C60 / BCP electron transport layer: 25 nm of C60 was thermally evaporated at a rate of 0.5 Å / s, followed by 6 nm of BCP at a rate of 0.2 Å / s, under high vacuum (<4 × 10 -6 Torr).

[0161] 6. Deposition of electrode: 100 nm of silver or gold was thermally evaporated at a rate of 1 Å / s to form the top electrode of the perovskite solar cell, under high vacuum (<4 × 10 -6 Torr).

[0162] Example 8 PSC structure characterization and electrochemical performance ​The device structure of PSC is glass / ITO / active layer / passivation layer / SnO. x / Ag simple stacking ( Figure 2 In this structure, the active layer is composed of Cs doped with [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz). 0.05 FA 0.95 PbI 2.94 Br 0.06 (where FA is formamidin) composition, which is prepared by a one-step chemical deposition process that is particularly effective for constructing inverted PSCs. ETL SnO is then deposited using ALD. x It is deposited on the active layer.

[0163] To achieve efficient electron transport, the dosing ratio of tetramethylaminotin (IV) (TDMASn) to water [TDMASn dosage (ms): H2O dosage (ms); 25:20, 50:20, 100:20, 150:20, 200:20, and 250:20] and the deposition cycles (50 to 500 cycles) were adjusted. Figures 3 to 7 The X-ray photoelectron spectroscopy (XPS) showed that SnO had a 25:20 ratio. x The closest stoichiometric ratio to SnO2. As the TDMASn:H2O ratio increases, SnO... x The x-value gradually decreases.

[0164] Device performance under different TDMASn:H2O ratios and different deposition cycle numbers ( Figure 8 , Figures 9A to 9C , Figures 10A to 10C , Figures 11A to 11C , Figures 12A to 12C , Figures 13A to 13C , Figures 14A to 14C , Figures 15 to 17 The study was conducted, and the passivation layer was also optimized. Figures 18A to 18D and Figure 19 The survey showed that performance was optimized when the ALDTDMASn:H2O ratio was 50:20 and deposition was performed for 300 cycles. Specifically, the ratio of glass / ITO / active layer / 300 cycles of SnO was [missing information]. x (Sn:O=50:20) / Ag achieved a PCE of 21.8% (e.g.) Figure 20 As shown; the open-circuit voltage (VOC) is 1.16 V, and the short-circuit current density (J) is... SC The value is 25.5 mA / cm. 2 (and the fill factor (FF) is 73.7%).

[0165] Note that compared to C-based 60 Devices (Figure 21 Compared to using SnO x The device used for ETL has an FF defect. Although it appears that C 60 and SnO x The difference in conductivity was not significant. Figure 22 However, it is believed that a potential cause of FF loss may be transmission resistance. Furthermore, Figures 23A to 23F and Figures 24A to 24E Ultraviolet-visible (UV-vis) spectroscopy and ultraviolet photoelectron spectroscopy (UPS) showed that SnO2, compared to commercial C60, x The conduction band minimum (CBM) matches the active layer better, indicating that the FF loss is independent of the energy misalignment between the ETL and the perovskite active layer.

[0166] Besides energy level alignment and transport capabilities, the interface between perovskite and ETL is believed to determine device performance by influencing carrier extraction efficiency and interface defect chemistry. In this case, SnO x The interface with perovskite was further redesigned. Specifically, in the preparation of SnO... x Before ETL, a layer called SnO is deposited with different TDMASn:H2O ratios and number of cycles (10 to 50 cycles). x(i) The intermediate layer. When SnO x(i) When the TDMASn:H2O ratio in the intermediate layer is 200:20 and deposition is performed for 30 cycles ( Figures 25 to 27 ; Specific process curves are as follows Figure 28 As shown, the device achieved a maximum PCE of 25.1%.

[0167] Unbound by theory, it was unexpectedly discovered that, in addition to the feed ratio of Sn to O source (i.e., the TDMASn:H2O ratio), oxygen vacancies in the intermediate layer can also be achieved by adjusting the Sn source purging time. Specifically, it is believed that the shorter the Sn source purging time, the more oxygen vacancies are created in the SnO2 layer. x The higher the likelihood of oxygen vacancies, the better. Specifically, shortening the purging time (from 20 seconds to 6 seconds and 13 seconds) means that excess TDMASn that did not participate in the reaction after the previous layer deposition cannot be completely removed. During the next layer deposition, excess Sn will deposit, forming SnO rich in Sn / O vacancies. x Membrane. In this embodiment, a three-step gradient setting with different Sn source purge times (6 s for the first 10 cycles; 13 s for cycles 10-20; 20 s for cycles 20-30) is used to achieve SnO. x(i) Oxygen defect gradient changes in the intermediate layer.

[0168] Optimized device current density-voltage (V) using reverse and forward scans J-V)Features Figure 29 )The resulting PCEs were 25.1% (V OC = 1.19 V, J SC = 25.8 mA / cm 2 , and FF = 81.8%) and 24.1% (V OC = 1.19 V, J SC = 25.7 mA / cm 2 , and FF = 78.9%). The corresponding steady power outputs were up to 24.95% (as shown in Figure 30 ). Figure 31 The corresponding external quantum efficiency (EQE) spectra in SC resulted in integrals J J-V that were indistinguishable from the values obtained by measurements. Moreover, the process was reproducible, as can be seen from the statistical distribution of all photovoltaic parameters of 20 devices in Figure 32 . The performance comparison of the different structured devices involved in this study is shown in Figures 33A to 33J .

[0169] Example 9 Interlayer characterization To investigate the specific effect of the interlayer, devices obtained with SnO x(i) interlayers deposited with different TDMASn:H2O ratios were subjected to electroluminescence quantum efficiency (EQE-EL) and defect density measurements, and the active layer / ETL films were subjected to photoluminescence (PL) characterization Figure 34 . The EQE-EL values increased with increasing TDMASn:H2O ratio of the SnO x(i) interlayer, from 3.9% for a TDMASn:H2O ratio of 25:20 to 11.0% for a TDMASn:H2O ratio of 200:20 Figure 35 , which was attributed to a reduction in non-radiative recombination and energy losses.

[0170] Moreover, the trap-filled-limit voltage (V TFL ) and the PL intensity showed opposite trends. Both gradually decreased with increasing TDMASn:H2O ratio of the SnO x(i) interlayer (specific results are shown in Figures 36A to 36G and Figure 37 ), which indicated that the oxygen deficiency situation in the SnO x(i) interlayer inhibited the defects and promoted the carrier extraction. In addition, PL mapping was performed on the SnO x / active layer films and the SnO x / SnO x(i) / active layer films, respectively Figure 38and Figure 39 ) indicates SnO x The broader PL intensity distribution of the active layer indicates non-uniform charge extraction. In contrast, SnO x(i) The introduction of the interlayer leads to a reduction in PL intensity and the films exhibit more uniform PL emission, further validating the improved and homogenized carrier extraction in the SnO x / SnO x(i) films. The surface morphology of the SnO x and SnO x(i) treated films, cross-sectional images of the devices, and the thickness of the SnO x and SnO x(i) films are shown in Figures 40 to 42 and Figures 43A to 43C .

[0171] Example 10 Theoretical studies Density functional theory (DFT) calculations were performed on various interfaces involving SnO x and perovskite. The calculations were based on uncharged heterostructures at the Perdew-Burke-Ernzerhof (PBE) + spin-orbit coupling (SOC) level implemented in the Vienna ab initio simulation package (VASP) 6.4. The results are shown in Figures 44A to 44D and Figures 45A to 45D , with detailed data shown in Figure 46 , Figures 47A to 47D , Figures 48A to 48C and Figures 49A to 49C , where the charge distribution and partial density of states (pDOS) at the interface are compared with and without SnO x(i) (V O ) plate and PDINN buffer layer (where V O refers to oxygen vacancies). The pristine SnO2and SnO x(i) (V O ) with oxygen vacancies were chosen to elucidate the effect of oxygen vacancy formation (i.e., TDMASn:H2O ratio from 25:20 to 200:20) on the charge carriers. Since the PDINN molecule can generate a very large supercell and a strong lattice mismatch, only one amino side chain was retained instead of the two originally designed, while the other side was adopted with a methyl group.

[0172] The Sn 4+ and I - that are externally adjacent are generally highly chemically reactive, especially when they are directly combined with the hetero component at the interface. The formation of V O structures ( Figure 44B ) can be viewed as a result of partial reduction of Sn 4+ cations, in contrast to pristine SnO2(Figure 44A Compared to the perovskite layer, it exhibits a higher space charge density distribution at the conduction band (CB) edge. Due to the strong interaction between the perovskite layer and the SnO2 layer, the violently twisted Pb-I framework often directly bonds to the SnO2 layer (e.g., Figure 46 (As shown). Therefore, the interfacial perovskite structure bonded to SnO2 has the same CB edge energy level as SnO2 (as shown). Figure 44A , Figure 45A , Figure 47A and Figure 48A This eliminates the band shift between SnO2 and the perovskite layer, while also weakening the carrier transport tendency at the interface. Furthermore, due to V... O Defects and strong surface interactions further induce SnO x(i) The band gap between the CB edge and the valence band (VB) edge of the perovskite shifts downward. Figure 44B , Figure 45B , Figure 47B and Figure 49A Conversely, at the SnO2 / PDINN / perovskite interface, due to the introduction of the PDINN molecular layer, SnO2 tends to further separate from the perovskite, and the perovskite framework tends to shrink inward, thereby avoiding excessive interaction between the perovskite and SnO2 surfaces.

[0173] After introducing the PDINN molecular buffer layer (such as...) Figure 44C As shown (in the diagram), it is noteworthy that in the vacancy-free structure, no effective space charge distribution appears at the interface within the planar polycyclic aromatic backbone of PDINN, while only a partially effective space charge distribution appears at the amino side chain. Similarly, Figure 45C and Figure 47C as well as Figures 48A to 48C The pDOS data shows a significant decrease in the DOS peak at the CBM edge, indicating a reduced likelihood of carrier distribution in this region. This result suggests that the polycyclic aromatic backbone of PDINN does not promote charge transport, but rather acts as a buffer in the ALD process due to its hydrophobicity. This prevents H₂O from directly contacting and reacting with the halide perovskite. Figures 50A to 50D As demonstrated by XPS analysis. Specifically, compared to the original perovskite, the perovskite / SnO... x The I3d peak in the interface shows increased width. Figure 50A and Figure 50B This could be attributed to new chemical substances or simply an increase in disorder at the interface. The introduction of PDINN mitigated this chemical change. Furthermore, in Figure 50C and Figure 50D In the middle, perovskite / SnO xThe Pb 4f peak in the samples showed a significant shift and broadening, which may be related to the formation of Pb oxide. Conversely, the Pb peak in the samples with the PDINN interface layer showed a very small shift compared to the pristine perovskite (PVK) surface, which may be attributed to the electron-withdrawing effect of the aromatic structure of PDINN, leading to a decrease in the electron cloud density of the perovskite surface. These results suggest that PDINN helps prevent interfacial chemical interactions.

[0174] For SnO x(i) / PDINN / V at the perovskite interface O exist( Figure 44D The presence of oxygen vacancies leads to SnO adjacent to the polycyclic aromatic moiety of PDINN. x(i) A space charge density contribution appears. Similarly, the CBM peak in pDOS ( Figure 45D and Figure 47D ,as well as Figures 49A to 49C It exhibits stronger dispersion than in the vacancy-free reference. This is due to the SnO2 caused by the PDINN layer. x(i) There is no direct contact between the layer and the perovskite layer, and the strongly dispersed CBM peak range compared to the baseline results in a reduced negative "spike" band shift. Figure 44C and Figure 45C This further reduces energy loss during carrier extraction and transport. These first-principles calculations collectively demonstrate that V O The presence of defects increases carrier transport, thereby activating SnO by introducing carrier distribution into the polycyclic aromatic backbone of the PDINN layer. x(i) / PDINN / perovskite interface. This conclusion is also considered applicable to the mF-PEAI and PDINN dual-additive interface, because PDINN exhibits a stronger conjugation effect compared to the isolated monoaromatic ring of mF-PEAI, thus dominating the charge density contribution, as... Figures 51A to 51F As demonstrated. Specifically, it is believed that the main function of mF-PEAI is to passivate the perovskite surface, thereby forming a molecular passivation layer or a 2D perovskite layer to prevent contact with defective SnO. x(i) Direct interaction. This layer optimizes interfacial charge transfer and prevents structural mismatch. The strongly conjugated polycyclic aromatic backbone of PDINN can lead to SnO adjacent to the polycyclic aromatic moiety of PDINN. x(i) The enhanced spatial extent of carrier transport contribution, especially in the presence of oxygen vacancy defects, is due to their stronger conjugation effect compared to the isolated monoaryl rings of mF-PEAI. Both PDINN and mF-PEAI act as buffers and passivation layers during the ALD process due to the absence of oxygen vacancies.

[0175] Example 11 Operational stability The encapsulated devices were placed in air, subjected to continuous 1 sun illumination (following ISOS-L-2 protocol), and monitored for device performance at 65 °C and MPPT. Devices based on SnO x exhibited excellent stability, retaining more than 95% of the initial PCE after 2000 hours of continuous operation (T 95 > 2000 hours. Figure 52 ) In addition, to obtain certified stability results, devices based on SnO x were sent to a third-party institution for stability testing and exhibited superior stability of more than 97% of the initial PCE after 1000 hours of continuous operation (as shown by the dashed box in Figure 52 ). Figure 53 A comparison of some reported stability results is detailed. In contrast, the control devices maintained relatively stable performance within the first 100 hours, but the PCE dropped to 80% of the initial value after 950 hours of continuous operation. Similar trends were observed during accelerated testing at 85 °C and 1 sun illumination Figure 54 ).

[0176] To gain insight into the differences in device operational stability, time-of-flight secondary ion mass spectrometry (TOF-SIMS) tests were performed on the devices before and after stability testing. For the control devices in Figure 55A and Figure 55B , a small amount of I - ions penetrated into the C 60 / BCP layer and contacted the Ag electrode. After stability testing, the diffusion of I - ions was enhanced, as evidenced by a large amount of I - ions penetrating into the C 60 / BCP layer and into the Ag electrode Figure 56A and Figure 56B . For the devices based on SnO x , I x ions did not show significant diffusion in the devices before and after aging under the protection of SnO - ( Figure 57A and Figure 57B ). This result indicates that the photo-thermal stability of the devices based on SnO x comes from the protection of the SnO x layer to the perovskite layer, making it difficult for ion diffusion and potential phase separation to occur under the dual influence of high temperature and light.

[0177] Further reference to Figure 56A and Figure 56B as well as Figure 57A and Figure 57B , it is observed that the Sn+ and CH5N2 + . The possible reason for this change could be the thermal decomposition of the organic cation (e.g., CH5N2 + ) and its chemical reaction with Sn ions. Under long-time heating and exposure of 2000 hours, the organic cation could decompose, which would first change its distribution at the interface and thus affect its TOF-SIMS signal. In addition, the decomposition products of the organic cation could react with Sn + , changing the chemical environment or oxidation state of Sn, and thus changing the emission efficiency of Sn + secondary ions. This could be the main reason for the 5% efficiency loss observed for the SnO x based device after aging for 2000 hours.

[0178] Thermal cycling tests were also performed, which is a common test used by the International Electrotechnical Commission (IEC) for outdoor conditions and commercialization. For the test (-40 °C to 85 °C, dark; ISOS-T-3), the SnO x based device showed about 4.7% average degradation after 800 thermal cycles (as shown in Figure 58 ), exceeding the 200 thermal cycles commonly performed for this test protocol. After going through the same conditions, the control device showed a 28.1% average efficiency reduction.

[0179] The environmental stability of SnO x based PSCs and traditional inverted PSCs (referred to as control devices) was investigated according to multiple sets of standard environmental stability tests, including ISOS-D-1, ISOS-D-3, ISOS-LC-1, and ISOS-O-1. For the ISOS-D-1 stability test shown in Figure 59 and Figure 60 , after 2000 hours of storage at 23° ± 4 °C and 46 ± 7% relative humidity (RH), the encapsulated and unencapsulated SnO x based devices showed almost no performance degradation and maintained more than 99.1% of their initial PCE for 2000 hours. The unencapsulated control device exhibited significant performance degradation (PCE dropped to 76.4% of the initial value after 300 hours), while the encapsulated control device could still maintain 98.9% of the initial PCE after 2000 hours of storage. The results indicate that the SnO x layer can effectively weaken the damage of water and oxygen around the perovskite, thus effectively achieving self-encapsulation of the device.

[0180] Further high-temperature and high-humidity storage at 85°C and 85% RH (ISOS-D-3) was conducted. For example... Figure 61 As shown, after 1000 hours of storage, the unencapsulated SnO-based... x The device exhibited a degradation of <3.0%. Furthermore, packaging it did not significantly improve its stability. Figure 62 The degradation decreased from 3.0% to 2.1%. In contrast, the packaged control device showed a degradation of >16.4%, indicating that external packaging alone is insufficient to withstand the impact of extreme environments. Furthermore, an on-off stability test (ISOS-LC-1) was conducted in an indoor environment. Figure 63 As shown, after 42 12-hour on-off test cycles at 23℃ ± 4℃ and 46±7% RH, the unencapsulated SnO-based... x The device showed a 2.5% PCE degradation, while the packaged control device showed a 9.7% degradation.

[0181] Example 12 Operational stability The stability of the device under outdoor aging conditions (ISOS-O-1) was investigated. Since outdoor temperature, relative humidity, and solar radiation intensity all affect device stability, we tracked changes in these parameters during the outdoor aging test. Figure 64 and Figure 65 After being placed in an outdoor environment for 50 days, the unencapsulated SnO-based x The device showed only 1.1% degradation, indicating that the self-encapsulated SnO-based device... x The device is virtually unaffected by outdoor environments. In contrast, the packaged control device exhibits a relatively large degradation of 4.8%. These stability results validate the effectiveness of SnO. x The device employs a self-encapsulating mechanism. This mechanism inhibits external moisture and oxygen permeation, thereby extending device lifetime. It also inhibits ion diffusion from the perovskite layer to the ETL or electrodes, thus maintaining device performance. Figure 66A In contrast, control devices with an additional encapsulation layer experience adhesive aging, which can lead to encapsulation failure. Figure 66B Photos of original components and packaged components are shown below. Figure 67 As shown. The encapsulation layer above the electrode cannot prevent ion diffusion that may occur during long-term operation.

[0182] The invention is given by way of example only, and various other modifications and / or alterations may be made to the described embodiments by those skilled in the art without departing from the scope of the invention as specified in the appended claims.

Claims

1. A perovskite solar cell comprising an electron transport layer between an anode and a cathode, wherein the electron transport layer consists of a first portion of tin oxide SnO x and a second portion of tin oxide.

2. The perovskite solar cell of claim 1, wherein the first portion of tin oxide and the second portion of tin oxide have different stoichiometries.

3. The perovskite solar cell of claim 2, wherein the SnO of the first portion and the second portion x x is 1.81 to 1.

98.

4. The perovskite solar cell of claim 1, wherein the first portion of tin oxide is disposed on the second portion of tin oxide.

5. The perovskite solar cell of claim 4, wherein the first and second portions of tin oxide have different thicknesses.

6. The perovskite solar cell of claim 5, wherein the thicknesses of the first and second portions of tin oxide are in the range of 2 nm to 50 nm.

7. The perovskite solar cell of claim 4, wherein the thickness of the first portion of tin oxide is less than the thickness of the second portion.

8. The perovskite solar cell of claim 4, wherein x of SnO in the first portion is less than x of SnO in the second portion. x x ​​ 9. The perovskite solar cell of claim 8, wherein x of SnO in the first portion is 1.83 and x of SnO in the second portion is 1.

96. x x ​​ 10. The perovskite solar cell of claim 7, wherein the thickness of the first portion is 2 nm to 10 nm and the thickness of the second portion is 15 nm to 50 nm.

11. The perovskite solar cell of claim 1, further comprising a passivation layer between the electron transport layer and the perovskite active layer.

12. The perovskite solar cell of claim 11, wherein the passivation layer is disposed under the first portion of the electron transport layer.

13. The perovskite solar cell of claim 11, wherein the passivation layer comprises a phenethylamine salt and a perylenediimide-based compound.

14. The perovskite solar cell of claim 13, wherein the phenethylamine salt is selected from the group consisting of phenethylammonium iodide, phenethylammonium bromide, phenethylammonium chloride, m-fluorophenethylammonium iodide, o-fluorophenethylammonium iodide, trifluoromethylphenethylammonium iodide, 4-methoxyphenethylammonium iodide, and 4-fluorophenethylammonium iodide, and combinations thereof.

15. The perovskite solar cell of claim 13, wherein the perylenediimide-based compound is selected from the group consisting of N,N'-bis{3-[3-(dimethylamino)propylamino]propyl}perylene-3,4,9,10-tetracarboxylic acid diimide, N,N'-bis{3-[3-(dimethylamino)propyl]amino}perylene-3,4,9,10-tetracarboxylic acid diimide, N,N'-bis{3-[3-(dimethylamino)propyl]amino}perylene-3,4,9,10-tetracarboxylic acid diimide N-oxide, N,N'-bis{3-[3-(dimethylamino)propyl]amino}naphthalene-1,4,5,8-tetracarboxylic acid diimide, and combinations thereof.

16. The perovskite solar cell of claim 13, wherein the molar concentration ratio of the phenethylamine salt and the perylenediimide-based compound is 4: 1 to 1:

4.

17. The perovskite solar cell of claim 11, wherein the perovskite active layer comprises a perovskite material of the formula Cs x MA y FA 1-x-y Sn z Pb 1-z I 3-m Br m wherein x is 0-0.5, y is 0-0.5, z is 0-0.5, and m is 0-1.

5.

18. The perovskite solar cell of claim 17, wherein the perovskite material is doped with a hole transport material selected from the group consisting of 2PACz, methoxy-2PACz, methyl-4PACz, bromo-2PACz, CbzBF, 4PADBC, and CbzBT, and combinations thereof.

19. The perovskite solar cell of claim 1, wherein the anode comprises a conductive material deposited on a transparent substrate, the conductive material selected from the group consisting of indium tin oxide, fluorine-doped tin oxide, niobium-doped titanium dioxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, and combinations thereof.

20. The perovskite solar cell of claim 1, wherein the cathode comprises a metal selected from the group consisting of gold, silver, copper, aluminum, nickel, and combinations thereof.

21. The perovskite solar cell of claim 1, which is an inverted perovskite solar cell.

22. A method for preparing the perovskite solar cell of claim 1, comprising the step of depositing an electron transport layer consisting of a first portion of tin oxide SnO x and a second portion of tin oxide on a surface-passivated perovskite active layer.

23. The method of claim 22, wherein the depositing is by way of atomic layer deposition.

24. The method of claim 23, wherein the atomic layer deposition comprises the steps of: (a) contacting the surface-passivated perovskite active layer with a pulse of tin vapor in a reaction space, followed by contacting the surface-passivated perovskite active layer with a pulse of oxygen vapor in the reaction space, to form the first portion of tin oxide; and (b) contacting the first portion of tin oxide with a pulse of tin vapor in the reaction space, followed by contacting the first portion of tin oxide with a pulse of oxygen vapor in the reaction space, to form the second portion of tin oxide.

25. The method of claim 24, wherein step (a) is repeated for 10 to 50 cycles.

26. The method of claim 24, wherein step (b) is repeated for 50 cycles to 500 cycles.

27. The method of claim 24, wherein the pulse of tin vapor is contacted with the surface- passivated perovskite active layer for 120 ms to 400 ms in step (a).

28. The method of claim 24, wherein the pulse of oxygen vapor is contacted with the surface- passivated perovskite active layer for 5 ms to 20 ms in step (a).

29. The method of claim 24, wherein the pulse of tin vapor is contacted with the first portion of tin oxide for 20 ms to 100 ms in step (b).

30. The method of claim 24, wherein the pulse of oxygen vapor is contacted with the first portion of tin oxide for 10 ms to 40 ms in step (b).

31. The method of claim 24, wherein each of step (a) and step (b) further comprises a step of purging the reaction space.

32. The method of claim 31, wherein the step of purging the reaction space consists of: purging the reaction space after the pulse of tin vapor is applied and before the pulse of oxygen vapor is applied; and purging the reaction space after the pulse of oxygen vapor is applied.

33. The method of claim 25, wherein purging the reaction space in step (a) is different between a first cycle and a second cycle.

34. The method of claim 33, wherein the number of cycles is divided into a first group, a second group, and a third group, the time of purging the reaction space increasing from the first group to the third group.

35. The method of claim 31, wherein the time of purging the reaction space after the pulse of tin vapor is applied in step (a) is 20 seconds. ​ 36. The method of claim 24, wherein the atomic layer deposition is performed at a temperature of 85 °C to 125 °C.

37. The method of claim 24, wherein the gas phase tin comprises tetrakis(dimethylamino)tin and the gas phase oxygen comprises water.

38. The method of claim 31, further comprising the steps of: (i) providing an anode comprising an electrically conductive material; (ii) depositing a perovskite active layer on the anode; (iii) subjecting the perovskite active layer to a surface passivation treatment; and (iv) providing a cathode over the electron transport layer by way of thermal evaporation.

39. The method of claim 38, wherein step (ii) comprises the steps of: spin coating the precursor solution on the anode; and A precursor solution is provided comprising: x MA y FA 1-x-y Sn z Pb 1-z I 3-m Br m CsI, FAI, MAI, MABr, PbBr2, PbI2, and SnI2, where x is 0-0.5, y is 0-0.5, z is 0-0.5, m is 0-1.5, and a hole transport material; annealing the spin-coated anode to form the perovskite active layer thereon.

40. The method of claim 39, wherein the concentration of the hole transport material in the precursor solution is 0.15 mg / mL to 1.2 mg / mL.

41. The method of claim 38, wherein step (iii) comprises the steps of: spin coating a surface passivation solution comprising a phenethylamine salt and a perylenediimide-based compound on the perovskite active layer obtained in step (ii); and annealing the spin-coated perovskite active layer to form a passivation layer thereon.

42. The method of claim 41, wherein the initial concentration of the phenethylamine salt is 0.5 mg / mL to 4 mg / mL and the initial concentration of the perylenediimide-based compound is 0.5 mg / mL to 8 mg / mL.

43. The method of claim 42, wherein the volume ratio of the phenethylamine salt to the perylenediimide-based compound is 1:

1. ​ ​ ​

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