Dispersion Behavior of High- <i>k</i> Perovskite Nanosheets for Ink Formulation and Device Printing

Solution-processable high-k perovskite nanosheets show considerable potential for applications in printed electronics due to their unique structural properties and exceptional physical characteristics. However, their dispersibility and compatibility in various organic solvents remain insufficiently understood, with a lack of systematic investigation, which restricts their broader application potential. In this study, the dispersion behavior of high-k perovskite nanosheets, specifically Ca2Nb3O10 (CNO) and Ca2NaNb4O13 (CNNO), was examined in 20 different organic solvents. By correlating the physicochemical properties of these solvents, including surface tension, dielectric constant, and empirical solvent parameters, with Hildebrand and Hansen solubility models, we identified the underlying solvent–nanosheet interaction mechanisms responsible for dispersion stability. Polar protic solvents, such as water and methanol (MeOH), as well as polar aprotic solvents, like dimethyl sulfoxide (DMSO), acetonitrile (ACN), N,N-dimethylformamide (DMF), propylene carbonate (PC), and N-methyl-2-pyrrolidone (NMP), facilitate uniform and stable nanosheet dispersions. These solvents promote dispersion stability through strong dipole–dipole interactions and moderate surface tension matching. Based on these findings, we developed a series of organic solvent-based inks incorporating high-k perovskite nanosheets, demonstrating excellent printing adaptability for electrical device fabrication, and achieving stable device performance. This work provides a comprehensive library of organic solvents that effectively disperse high-k perovskite nanosheets, thereby broadening their potential applications in printed electronic devices.