Four low-fluorine solutions with different stoichiometry of Y: Ba: Cu= 1: 2: ξ (ξ= 3, 3.5, 4, 4.5) were prepared using Ba-TFA, yttrium and copper acetate as precursors. YBa2Cu3O7− δ (YBCO) films derived from these low-fluorine solutions were coated on LaAlO3 (LAO) single crystal substrates by dip-coating process. The effect of copper stoichiometry in precursor solution on the microstructure and superconductivity of YBCO films was studied. The ...