Construction of Zn ₂ SnO ₄ Solubility Phase Diagrams via Processing–Structure–Property Mapping for Precise Powder Synthesis

ABSTRACT Zn 2 SnO 4 (ZTO) is a promising indium‐free transparent conductive oxide for next‐generation display applications, where powder purity, stoichiometry, and phase stability are critical for sputtering‐target fabrication. This study establishes a processing framework that enables the controlled hydrothermal synthesis of high‐purity (∼99.95 wt%, 3N5), nanosized (∼60 nm) ZTO powders by correlating solution chemistry with phase formation. Systematic solubility–pH, solubility–concentration (Zn/Sn ratio), and solubility–temperature diagrams were experimentally constructed to define the thermodynamic and kinetic boundaries governing ZTO nucleation and growth. These diagrams reveal narrow synthesis windows that yield single‐phase ZTO through balanced supersaturation and controlled precipitation dynamics. The influence of synthesis conditions on phase purity, crystallinity, and morphology was further validated using XRD, FTIR, SEM, TEM, and EDX. The resulting three‐dimensional solubility map provides a predictive tool for reproducible and scalable ZTO powder production, enabling the design of powders suitable for densification into ceramic sputtering targets for transparent electronic applications.