Organic-inorganic hybrid perovskite batteries After more than 10 years of rapid development, its photoelectric conversion efficiency has been comparable to that of monocrystalline silicon cells, while further improving the efficiency and stability of the battery, promoting its industrialization has been put on the agenda. Among them, in the process of expanding small-area devices to large-area modules, the loss of battery performance caused by energy loss is one of the core problems that need to be solved urgently in current scientific and industrial research, and it is of great significance for further improving the efficiency of perovskite battery modules and promoting its large-area and industrialization.
Figure 1. Performance characterization of small-area perovskite solar devices under material modification
The Meng Qingbo team of the Institute of Physics of the Chinese Academy of Sciences/Beijing National Research Center for Condensed Matter Physics is the earliest team in China to carry out research on perovskite batteries, and has carried out systematic research on the preparation of high-quality perovskite films, battery efficiency and stability improvement, and developed a series of bulk phases, interface regulation methods and related stability studies. For example, the stability of interfacial passivation is proposed for the first time to be crucial to the overall stability of the device, and the intermolecular π-π conjugate of tribenzylphosphine oxide (TBPO) is used to induce the formation of surface molecular superstructures, and the coordination and passivation of highly stable TBPO-perovskite are obtained, which significantly improves battery efficiency, interfacial stability and battery device stability (Adv. Mater., 2020, 20, 1907356) Developed a method to quantify the interfacial defects of perovskite batteries by introducing hydrophobic polystyrene materials into perovskite films and anterior interface, respectively, the former can effectively inhibit the volatilization and phase separation of perovskite film components, and the latter can release interfacial stresses and can also be used as an internal packaging material to further improve device stability (Adv. Energy Mater., 2019, 9, 1901352；Nano Energy, 2018, 43, 383; Adv. Funct. Mater., 2019, 29, 1905336）。 At present, the team has obtained 18 national authorized invention patents and 5 utility model patents in the field of key materials and technologies for perovskite solar cells.
Figure 2. Schematic diagram of the mechanism of anionic bifunctional molecules regulating the crystallization and defect of perovskite thin films
Figure 3. Device stability and performance characterization of large-area modules
Recently, in response to the problem that the crystallization process is prone to lattice distortion, phase separation and defect centers due to the mismatch of FA and Cs ions in the FA-Cs perovskite system, which is not conducive to obtaining a large-area uniform perovskite film due to the mismatch of FA and Cs ions, Dr. Li Yiming, a clean energy materials testing and diagnosis and R&D platform of the Clean Energy Research Department of the Clean Energy Laboratory/ Huairou Research Department, cooperated with Shi Jiangjian, Li Dongmei and Meng Qingbo to design a bifunctional material isobutylamine dithiocarbamate ( iBA-iBDTC)。 It is directly introduced into the perovskite precursor solution, and the CSS-anionic group and Pb coordination in iBA-iBDTC during the growth of perovskite crystals can improve Pb-I nucleation and FA-Cs perovskite crystallization, while long-chain iBA+ cations are distributed on the surface and grain boundaries of perovskite films, which can passivate defects, reduce surface energy and stabilize the surface interface structure. The small area perovskite solar cell achieves a photoelectric conversion efficiency of 24.25%, and > 20.5% certification efficiency on the 10 cm battery module, which is one of the high efficiencies of the currently reported perovskite module. This synergistic effect of crystallization regulation and surface interface passivation provides a more feasible technical route for promoting the development and industrialization of perovskite photovoltaics.
Figure 4. Battery module certification efficiency
The findings were published in Joule 6 (2022) 676 under the title "Efficient, stable formamidinium-cesium perovskite solar cells and minimodules enabled by crystallization regulation" This study was supported by the National Natural Science Foundation of China (51872321, 11874402, 52172260, 52072402, 52102332, 51627803).
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