Inkjet printing of metal oxide coatings for enhanced photovoltaic soiling environmental applications

BACKGROUND AND OBJECTIVES: Global energy needs have gradually shifted toward photovoltaic solar energy, especially in the Gulf region because of the high solar-irradiance potential. However, one of the main challenges for this technology in the region is soiling, which has been reported to degrade the power output of photovoltaic modules significantly. Anti-soiling coatings are promising technologies to minimize the effect of dust on photovoltaic solar panels. Accordingly, this study aimed to synthesize aluminum, zinc, titanium, and tin oxides using mixed-based and nanoparticle-based precursors through inkjet printing techniques and investigate their potential in anti-soiling applications for PV panels. METHODS: Four metal oxides, namely, aluminum, zinc, titanium, and tin oxides, were synthesized and deposited using the inkjet printing technique for anti-soiling application. Ultraviolet-visible spectroscopy, field emission scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, and contact angle measurements were performed to characterize these thin films. FINDINGS: The optical transmittance of the substrate using the nanoparticle ink revealed better optical properties than that using the mixed-based ink. Compared with nanoparticle samples, a homogeneous crack and a defect-free layer were observed with dense nanoparticles in all mixed inks (except for aluminum oxide ink). The contact angles indicated that the synthesized films were super-hydrophilic/ hydrophilic coatings. The results of the outdoor testing revealed that up to 60% less dust was deposited on the best-performing film (aluminum oxide mixed-based ink) compared with bare glass. CONCLUSION: The outdoor experiment revealed that mixed-based thin films were better in reducing dust deposition than nanoparticle-based thin films and bare glass. This enhancement might be due to the decreased antireflection property along with a morphological contribution related to the presence of nanoparticle voids, which reduce the spectra scattering and minimize its deterioration, thus demonstrating better anti-soiling properties. The results of the outdoor test revealed that aluminum, zinc, and titanium oxides are promising materials for anti-soiling coating applications for both ink types. However, tin oxide coatings are not recommended for anti-soiling applications, as they showed the highest dust deposition rate near the bare glass performance.