In this paper, indium-doped zinc oxide (IZO) films were grown by spray pyrolysis, using zinc acetate and indium acetylacetonate precursors. The focus was on developing a solution recipe based on water as solvent, with only minor acetic acid content, as well as keeping the substrate temperature as low as possible—at 360 °C. The process is therefore environment friendly and energy efficient. Despite the challenging conditions, the resulting IZO films were highly transparent and conductive. Their texture deviates strongly from the (002) texture of ZnO and depends on the indium content, which also influences the resistivity. The latter attains its minimum for an indium concentration of 4 at.% in the solution and decreases for increasing film thickness, reaching the value of (5.0 ± 0.1) × 10⁻³ Ω cm, mainly due to the increase in carrier mobility. The stability of the resistivity after high dose of UV irradiation was found to increase with the carrier density and the film thickness. Thick, highly doped films show minimal resistivity modification even after a total dose of 12.1 kJ/cm² UVA/UVB irradiation. Finally, to demonstrate its applicability in devices, the IZO electrode was used for the fabrication of a lead-perovskite absorber solar cell, yielding an energy conversion efficiency of 6% and 910 mV open-circuit voltage.

High-quality Ga ₂ O ₃ films are obtained by spray pyrolysis from aqueous solutions through optimization of the solution composition and the spraying process parameters.

A comparative study is presented on chemical bath-deposited ZnO films, doped with the group-13 metals Al, Ga and In. The study reveals marked differences in dopant incorporation in the films, which increases in the order: In, Al and Ga. The presence of dopant in the solution induces significant modifications in the deposition rate, which varies between 110 and 40 nm min⁻¹. All films are (002)-textured, whereas the lattice stress evolution with the dopant type and concentration suggests that Ga has the highest degree of substitutional incorporation in Zn sites. The average visible transmittance is higher than 80%, while the infrared reflectivity depends on the free carrier density in the films, which is the lowest for undoped ZnO and increases in the order: In-, Al- and Ga-doped ZnO. Optical measurements also yield an inverse correlation between carrier density and mobility. Doping enlarges the bandgap, as well as the Urbach energy that is related to the films’ disorder. The lowest electrical resistivity, measured by four-point probe, is 1.7 × 10⁻² Ω cm and is obtained for In-doped films after being exposed to ultraviolet light. Ga-doped films are found to exhibit the highest stability of the conductivity upon ultraviolet exposure.