High-performing superconducting YBa₂Cu₃O_7–x (YBCO) films are fabricated by a chemical solution deposition methodology through novel barium-deficient low-fluorine solutions. The precursor solutions, distinguished for being straightforward, inexpensive and eco-friendly, allow us to reduce the growing temperature of YBCO down to 750 °C. We investigated the influence of the growing temperatures on both the microstructure and superconducting properties of YBCO films by using conventional thermal annealing and flash-heating approaches. A clear correlation between the growing temperature (T_g) and the superconducting performance of the films was obtained with improved performances observed at low T_g.