Coating liquid for forming piezoelectric thin film, method of producing coating liquid for forming piezoelectric thin film, piezoelectric thin film, method of manufacturing piezoelectric thin film, and liquid ejection head

A method of producing a coating liquid for forming a piezoelectric thin film, comprising:

• heating at least three raw material compounds containing each of Pb, Ti, and Zr, or at least two raw material compounds including a complex raw material compound containing any two of Pb, Ti, and Zr and a raw material compound containing the remaining one of Pb Ti, and Zr, at a temperature of 120° C. or more in an organic solvent, to thereby form a complex metal compound containing Pb, Ti, and Zr;
• and
• hydrolyzing the complex metal compound by adding water to a system after the heating, to thereby form a complex precursor containing Pb, Ti, and Zr;
• wherein the heating is performed in the presence of at least one selected from the group consisting of 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-ene, and 1,4-diazabicyclo[2.2.2]octane, and
• wherein an exothermic peak of the coating liquid formed after the hydrolyzing is at a temperature of 400° C. to 450° C. in differential thermal analysis of the coating liquid.

A method of manufacturing a piezoelectric thin film, comprising:

• applying a coating liquid for forming a piezoelectric thin film containing lead zirconate titanate onto a substrate, the coating liquid comprising a complex precursor containing Pb, Ti, and Zr, and at least one selected from the group consisting of 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]non-5-ene, and 1,4-diazabicyclo[2.2.2]octane;
• and
• forming the piezoelectric thin film containing lead zirconate titanate by a sol-gel method,
• wherein an exothermic peak of the coating liquid is at a temperature of 400° C. to 450° C. in differential thermal analysis of the coating liquid.