CN-121985671-A - Titanate self-assembled monomolecular passivation layer and preparation method and application thereof

Abstract

The invention discloses a titanate self-assembled single-molecule passivation layer and a preparation method and application thereof, and belongs to the technical field of photovoltaic cells. By introducing a diisopropyl di (triethanolamine) titanate self-assembled molecular layer on the surface of the nickel oxide film, a stable molecular-level buffer interface is constructed between the nickel oxide and the perovskite light absorption layer. The titanate molecules can carry out coordination or condensation reaction with hydroxyl on the surface of nickel oxide, and interact with unsaturated nickel sites through a multidentate triethanolamine structure, so that the surface hydroxyl defects and the chemical activity of high-valence nickel ions are inhibited, and the interface defect state density and non-radiative recombination loss are obviously reduced. The passivation layer can be formed under mild conditions, the process is simple and is highly compatible with the preparation flow of the trans-device, and the photoelectric conversion efficiency and the long-term operation stability of the trans-perovskite solar cell can be synchronously improved on the premise of not increasing the structural complexity of the device.

Inventors

• HAO YAFENG
• LI TENGTENG
• LIANG TING
• WEI YUAN
• LEI CHENG

Assignees

• 中北大学

Dates

Publication Date

20260505

Application Date

20260330

Claims (10)

1. 1. A titanate self-assembled monomolecular passivation layer is characterized by being formed by self-assembling a titanate compound on the surface of a substrate through chemical bonding.
2. 2. The titanate self-assembled monomolecular passivation layer of claim 1, wherein the titanate compound is diisopropyl di (triethanolamine) titanate.
3. 3. A titanate self-assembled monomolecular passivation layer according to claim 2, wherein the diisopropyl di (triethanolamine) titanate molecule is bonded to the active group on the substrate surface via the titanate group and is multidentate via its triethanolamine group.
4. 4. The titanate self-assembled monolayer passivation layer of claim 1, wherein the substrate is a nickel oxide hole transport layer.
5. 5. The titanate self-assembled single molecule passivation layer of claim 1, wherein the titanate self-assembled single molecule passivation layer is disposed between the nickel oxide hole transport layer and the perovskite active layer of the trans-perovskite cell.
6. 6. A method of preparing a titanate self-assembled monomolecular passivation layer according to any one of claims 1 to 5, comprising the steps of: S1, providing a substrate; s2, dissolving titanate compounds in a solvent to prepare a precursor solution; s3, spin coating or knife coating the precursor solution on the surface of the substrate; S4, self-assembling the titanate compound on the surface of the substrate through heat treatment to form a single-molecule passivation layer.
7. 7. The method for preparing the titanate self-assembled monomolecular passivation layer according to claim 6, wherein the titanate compound is diisopropyl di (triethanolamine) titanate, the solvent is ethanol or isopropanol, and the concentration of the diisopropyl di (triethanolamine) titanate in the precursor solution is 1-5 μl/mL.
8. 8. The method for preparing a titanate self-assembled monomolecular passivation layer according to claim 6, wherein the heat treatment in step S4 is performed at a temperature of 60-80 ℃ for 2-5 minutes.
9. 9. Use of a titanate self-assembled single molecule passivation layer according to any of claims 1 to 5, in trans perovskite solar cells for modifying the interface between a hole transport layer and a perovskite active layer.
10. 10. The use of a titanate self-assembled monomolecular passivation layer according to claim 9, wherein the hole transport layer is a nickel oxide film, the perovskite active layer is a perovskite film, the perovskite film is ABX 3 , wherein a is Cs + 、CH 3 NH 3 + 、CH(NH 2 ) 2 + or mixed a-site, B is Pb 2+ 、Sn 2+ or mixed B-site, and X is Cl - 、Br - 、I - or mixed X-site.

Description

Titanate self-assembled monomolecular passivation layer and preparation method and application thereof Technical Field The invention relates to the technical field of photovoltaic cells, in particular to a titanate self-assembled single-molecule passivation layer, and a preparation method and application thereof. Background Organic-inorganic hybrid perovskite materials are widely regarded as a photovoltaic absorbing material with great potential because of a series of excellent photoelectric properties such as higher optical extinction coefficient, lower exciton binding energy, longer carrier life and the like. The photoelectric conversion efficiency of the perovskite solar cell constructed based on the material breaks through 26% in laboratory scale, and the perovskite solar cell shows a performance level exceeding that of the traditional silicon-based solar cell. Meanwhile, the perovskite solar cell has the remarkable advantages of relatively simplified preparation process, light weight, flexibility and the like, and is considered to be an important candidate for the next-generation commercial photovoltaic technology. The high efficiency of the perovskite solar cell is not only derived from the excellent electrical and optical properties of the hybrid perovskite material, but also is closely related to the reasonable selection and interface regulation of the materials of each functional layer in the device. Among them, nickel oxide (NiO x) is one of the commonly used hole transport layer materials in trans (p-i-n) perovskite solar cells, and is widely focused on in academia and industry because of its energy level position matching with perovskite valence band, high chemical stability, low raw material cost and suitability for solution method or low temperature process preparation. However, the nickel oxide hole transport layer still has a non-negligible limitation in practical applications. NiO with ideal stoichiometric ratio of 1:1 is intrinsically a Mort insulator, and in order to obtain sufficient hole conductivity, a practically prepared NiO x film usually introduces a higher concentration of nickel vacancy defects, so that high-valence nickel ions such as Ni 3+、Ni4+ are induced to be formed. The high-valence nickel species have strong chemical activity, are easy to carry out deprotonation reaction with organic cations (such as methylamine ions MA +, formamidine ions FA + and the like) in perovskite materials, accelerate interfacial chemical degradation, and introduce additional risk of device failure. In addition, the surface of NiO x thin films deposited by solution methods often contain a large number of reactive hydroxyl groups (from NiOOH and Ni (OH) 2 are equivalent). The surface hydroxyl groups can serve as negative charge centers electrically, so that the deprotonation reaction of organic cations in the perovskite layer is further aggravated, the surface hydroxyl groups can serve as carrier trapping centers easily in the hole transmission process, the probability of non-radiative recombination is remarkably improved, and the photovoltaic performance and the long-term stability of the perovskite solar cell are adversely affected. Therefore, a method for effectively performing chemical and electrical passivation on the surface of the nickel oxide hole transport layer is needed to inhibit the interface reaction, reduce the recombination loss and improve the extraction and transport efficiency of carriers. Disclosure of Invention The invention aims to provide a titanate self-assembled single-molecule passivation layer, a preparation method and application thereof, and aims to solve the problems that the nickel oxide hole transport layer in the existing trans-perovskite solar cell has high surface defect density, insufficient chemical stability, serious interface recombination and the like commonly existing in the nickel oxide hole transport layer by utilizing a passivation material di (triethanolamine) diisopropyl titanate to construct a stable molecular-level buffer interface between the nickel oxide hole transport layer and the perovskite active layer. Based on the above purpose, the invention provides a titanate self-assembled monomolecular passivation layer which is formed by self-assembling titanate compounds on the surface of a substrate through chemical bonding. Preferably, the titanate compound is diisopropyl di (triethanolamine) titanate (C 18H42N2O8 Ti). Preferably, the diisopropyl di (triethanolamine) titanate molecule is bonded to the active groups on the substrate surface via the titanate groups and is multidentate via its triethanolamine groups. Preferably, the substrate is a nickel oxide hole transport layer. Preferably, the titanate self-assembled monomolecular passivation layer is disposed between the nickel oxide hole transport layer and the perovskite light absorbing layer of the trans-perovskite cell. Preferably, the thickness of the titanate self-assembled monomolecular passi