A Strategy for Inkjet Printing of Two-Dimensional Potassium Molybdate Patch Array as the Precursor for Controlled MoO2 Growth

Journal article, 2025

Molybdenum dioxide (MoO2) has shown promise in flexible electronics and optoelectronic devices due to its good electrical conductivity and optical transparency. However, the precisely controlled growth of MoO2 remains challenging. High-quality MoO2 single crystals with lateral sizes up to 100 μm have been previously obtained by the molten-salt method using potassium molybdate as the precursor. Continuing that route, in order to achieve the controlled fabrication of MoO2 precursor arrays, this study employs inkjet printing to systematically regulate the composition and drying conditions of potassium molybdate (K2MoO4) inks. By introducing 30% ethylene glycol as a cosolvent, the coffee-ring effect is significantly suppressed through enhanced Marangoni flow. Quantitative image analysis further confirms that the deposition uniformity is maximized at 30 vol% ethylene glycol, where both edge and central width ratios reach their lowest levels. Additionally, performing inkjet printing on substrates heated to 85 °C effectively reduces droplet shrinkage, minimizing array misalignment and improving both pattern regularity and deposition uniformity. This solvent–temperature combined strategy provides a practical and scalable approach for the precise deposition of MoO2 precursors, offering new insights for the patterned construction of 2D materials.