An ultrathin Al layer was introduced into AZO/Cu/AZO films to further enhance the optoelectronic performance. The AZO/Al/Cu/AZO films were deposited on glass substrates by DC and RF magnetron sputtering; the microstructure and optoelectronic properties were analyzed by XRD, SEM, AFM, TEM, visible spectrophotometer, and Hall effect measurement system. The results indicated that the Al layer played a crucial role in modulating the crystallization behavior and optoelectronic properties of the films, exhibiting a distinct thickness-threshold effect. At an Al layer thickness of 1 nm, the film exhibited optimal optoelectronic performance, achieving a high F_OM of 0.71 Ω⁻¹, a high transmittance of 85%, and a low resistivity of 5.7 × 10⁻⁵ Ω·cm. However, when the Al layer thickness exceeded 1 nm, the crystallinity of the films deteriorated significantly, the grain boundary scattering and light absorption effect enhanced, leading to the deterioration of photoelectric properties. The introduction of the Al layer significantly improved the stability of the films, and the AZO/Al(2 nm)/Cu/AZO film exhibited the best temporal stability after being exposed to air for 20 months.

The TiAlMoN coatings were deposited by arc ion plating under different substrate bias voltages, and the effects of substrate bias on the composition, phase structure, microstructure, and mechanical properties of the coatings were systematically investigated. The results showed that, as the bias voltage increased from 0 V to −75 V, enhanced ion bombardment promoted coating densification, the N/(Ti + Al + Mo) atomic ratio decreased from 1.33 to 1.05, and the deposition rate increased from 124.7 nm/min to 138.2 nm/min. XRD peak fitting revealed that the TiAlMoN coatings may consist of three phases: c-TiN, fcc Mo-N, and c-AlN. With increasing negative bias voltage, the preferred (111) orientation became more pronounced, while the Mo-N phase gradually evolved from B1-MoN to γ-Mo₂N. As the substrate bias voltage increased, the grain size initially reduced and then slightly increased, and the compressive residual stress sharply increased from 0.68 GPa to 2.21 GPa. Owing to coating densification, grain refinement, and increased compressive residual stress, the hardness increased from 16.7 GPa to 33.9 GPa. The adhesion strength reached a maximum of 59.7 N at −25 V and decreased at higher bias voltages because of excessive residual stress. Appropriate control of the substrate bias voltage enables the synergistic optimization of structural strengthening and interfacial stability in TiAlMoN coatings.