One-step preparation of Cr2O3-based inks with long-term dispersion stability for inkjet applications

Inkjet printing of functional materials has shown a wide range of applications in advertising, OLED display, printed electronics and other specialized utilities that require high-precision, mask-free, direct-writing deposition techniques. Nevertheless, the sedimentation risk of the refractory functional materials dispensed in inks hinders their further implementation. Herein, we present a bottom-up ink preparation strategy based on Cr2O3 by a one-step solvothermal method. The obtained ink remained stable under an equivalent natural sediment test for 2.5 years. The chemical composition of the solvothermal product was characterized, and the mechanism of the superior dispersion stability of Cr2O3 particles was analysed. These amorphous Cr2O3 particles were capped by ligands generated via low-temperature solvothermal reactions. Ethanol and acetylacetone covering the particle surfaces play an essential role in enhancing the solubility of Cr2O3 particles in the solvent forming the ultrastable colloidal ink. Moreover, this ink was successfully printed using a direct-write inkjet system JetLab (R) II on nylon fabrics, and the printed area of the fabrics shows a spectral correlation coefficient of 0.9043 to green leaves. Finally, we believe that the one-step bottom-up fabrication method of Cr2O3-based pigment inks may provide a general approach for preparing metal oxide-based pigment inks with long-term dispersion stability.

Automated summary

A one-step solvothermal method was used to prepare Cr2O3-based pigment inks with long-term dispersion stability, demonstrating superior dispersion stability of the Cr2O3 particles capped by ligands. The ink remained stable under a natural sediment test for 2.5 years, and successful printing on nylon fabrics was achieved, showing a spectral correlation coefficient of 0.9043 to green leaves.