Method for improving light absorption layer of battery by using melamine as additive

Abstract

The invention discloses a method for improving a light absorption layer of a battery by taking melamine as an additive, which comprises the following steps of: dissolving tin iodide, formamide, melamine and tin fluoride in a mixed solvent of DMF and DMSO in proportion to prepare a precursor solution, spin-coating the precursor solution on a hole transport layer for 30 seconds, dripping anti-solvent chlorobenzene after spin-coating for 12 seconds, and then performing annealing treatment to obtain the light absorption layer. Due to the reduction performance of melamine, Sn <2+> can be inhibited from being oxidized into Sn <4+>, the formation of Sn vacancies is reduced, the generation of defects such as pinholes in the surface of the perovskite thin film is prevented, the surface appearance of the perovskite thin film is improved, and the power conversion efficiency of the battery is improved; nitrogen ions in the chemical structure have lone pair electrons and can form coordinate bonds with Sn<2+>, so that the crystallization rate in the perovskite forming process is slowed down and controlled, perovskite film coverage is more uniform and compact, and the efficiency and stability of the cell are improved.

Description

technical field [0001] The invention belongs to the technical field of solar cells, and in particular relates to a method for improving a light-absorbing layer of a cell by using melamine as an additive. Background technique [0002] In recent years, organic-inorganic hybrid solar cells have attracted much attention due to their simple structure, low preparation cost, suitable and adjustable bandgap, high extinction coefficient, bipolar carrier transport, and the ability to prepare flexible devices. The conversion efficiency has been increased from 3.8% to 25.2%. However, at this stage, such high-performance perovskite cells mainly use lead-halide perovskite materials as the light-absorbing layer, which seriously endangers the ecological environment and personal safety. Therefore, there is an urgent need to seek a non-toxic lead-free perovskite battery. [0003] In lead-free perovskite solar cells, germanium ions (Ge 2+ ), tin ions (Sn 2+ ), antimony ions (Sb 3 + ), bi...

AI Technical Summary

Problems solved by technology

However, due to the low vacancy formation energy of Sn, the Sn 2+ Very easily oxidized to Sn 4+ , and as one of the perovskite precursor materials, tin iodide (SnI 2 ) and organic amine salts are too fast, making the crystallization rate of perovskite so fast that it is difficult to obtain a uniform and dense perovskite film, which limits the improvement of the efficiency and stability of tin-based perovskite solar cells

[0004] Chinese patent CN 111952455 A discloses an ionic liquid type organic bulky amine molecular salt to prepare low-dimensional tin-based perovskite thin films and its solar cells and applications. It mainly uses a special ionic liquid type organic bulky amine molecular salt butylamine As the precursor liquid, the crystallization process of the low-dimensional tin-based perovskite is controlled by the strong interaction between the amine molecular salt and the tin-based perovskite framework, and then a thin film with a low defect state density and a smooth and dense surface is obtained. Improve the photoelectric conversion efficiency and device stability of solar cells, but this solution cannot effectively prevent Sn 2+ Oxidation, and the preparation of the precursor solution is relatively cumbersome, the source of the ionic liquid-type organic bulky amine molecular salt butylamine acetate is narrow, and it is difficult to obtain, which affects the overall preparation efficiency and is not conducive to large-scale production and application

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