A Universal Strategy of Intermolecular Exchange to Stabilize α‐FAPbI₃ and Manage Crystal Orientation for High‐Performance Humid‐Air‐Processed Perovskite Solar Cells

Abstract

preparing PSCs out of the glovebox to eliminate expensive costs is necessary for further commercialization. [8][9][10][11][12][13] Even the well-studied methylamine lead iodine (MAPbI 3 ) perovskites exhibit uncontrollable crystallization in humid air, resulting in rough and pinhole-containing perovskite films with multiple defects and thus limiting their performance. [14][15][16][17] Formamidine (FA)-based perovskites have a narrower bandgap and superior stability than MAPbI 3 and have been widely applied in the preparation of high-performance PSCs. [18][19][20] However, it is more difficult to obtain FA-based high-quality perovskite films in humid air, because moisture not only does harm to the quality of the perovskite films but also blocks the formation of the perovskite black phase. Photoactive black α-FAPbI 3 has difficulty forming in humid air and easily transforms to photoinactive yellow δ-FAPbI 3 when exposed to moisture. [21][22][23][24][25][26][27][28] Due to these adverse effects of moisture, humid-air-processed PSCs exhibit a greatly reduced PCE compared to inert-gas-processed PSCs. Perovskite films are commonly prepared by solution methods. Polar solvents such as dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or N-methyl pyrrolidone (NMP) are used to dissolve perovskite components, and they can easily bond with perovskite precursors. [29][30][31][32] Therefore, the crystallization and properties of perovskite films are closely related to the state of the solvent. High-quality perovskite films have frequently been obtained under inert gas. However, these polar solvents are sensitive to moisture, and their properties, such as volatility or solubility, [33,34] easily change in humid air, which makes the crystallization of perovskite films uncontrollable and causes inevitable problems, including carrier recombination or instability. Previous works have made great efforts to negate the negative effects of solvent changes in humid air. [9,35] Huang and co-workers reported that ionic liquid solvents have great potential for preparing different types of PSCs in humid air. [36][37][38] Increasing the temperature of the substrate is proven to be an efficient method to tune the crystallization kinetics by speeding up the volatilization of solvents in humid air, and this approach has been applied in several perovskite types. [12,39,40] In addition, Preparation of high-performance perovskite solar cells without strict environmental control is an inevitable trend of commercialization. Humidity is considered the main factor hindering perovskite performance. Formamidine (FA)-based perovskites suffer from the instability of photoactive black α-FAPbI 3, especially in humid air, and numerous defects in the surface and bulk of perovskite films limit their performance. In this work, long-chain n-heptylamine (nHA) is introduced via antisolvent engineering into an FA-based perovskite film. nHA removes the negative intermediate adduct and promotes the formation of α-FAPbI 3 at room temperature in humid air via intermo...

Constructing Efficient Hole Transport Material through π-Conjunction Extension for Perovskite Solar Cell

“…Detailed information on synthesis of materials, 1 H NMR, 13 C NMR, and HRMS spectra; density functional theory calculation, mobility and conductivity measurements, cyclic voltammetry measurement detail, calculation of HOMO and LUMO energy levels, the steadystate PL and TRPL measurements, and the electrochemical impedance spectroscopy (PDF)…”

Modulating preferred crystal orientation for efficient and stable perovskite solar cells—From progress to perspectives

“…The champion cell delivered a PCE of 23.7% with excellent stability. 162 Meng et al 161 employed a conjugated donor polymer (PTQ10) as an interfacial layer for the perovskite intermediate phase before thermal annealing. The PTQ10 treatment can significantly suppress the volatilization of the surface organic cations during thermal annealing.…”

“…At the same time, the nHA in the film can also reduce the defects and suppress ion migration. The champion cell delivered a PCE of 23.7% with excellent stability 162 . Meng et al 161 employed a conjugated donor polymer (PTQ10) as an interfacial layer for the perovskite intermediate phase before thermal annealing.…”

面向高稳定性太阳能电池开发的卤化物钙钛矿稳定 性提升策略

“…The additives can enhance the stability of precursor solution and reduce the crystal nucleus, getting large-size high-quality perovskite single crystals. Wang et al [14] demonstrated an intermolecular exchange strategy to prepare stable FA-based perovskites under an air environment, by introducing a longchain n-heptylamine (nHA) additive via antisolvent engineering. This strategy prompts the formation of α-FAPbI 3 and optimizes the grain orientation.…”