Physical Characteristics, Blue-Green Band Emission and Photocatalytic Activity of Au-Decorated ZnO Quantum Dots-Based Thick Films Prepared Using the Doctor Blade Technique

• Published in: Molecules (Basel, Switzerland) Switzerland), 2023-06, Vol.28 (12), p.4644
• Main Authors: Fatehmulla, Amanullah, Shamsan, Belqes A, El-Naggar, Ahmed M, Aldhafiri, Abdullah M, Qureshi, Nilam, Kim, Taesung, Atif, Muhammad, Mahmood, Asif, Asif, Mohammad
• Format: Article
• Language: English
• Subjects: Au nanoparticles; Biosensors; blue-green band emission; Catalysis; Catalysts; Catalytic activity; co-precipitation; Crystal structure; Crystals; Diffraction; Emissions; Environmental impact; Ethanol; Founding; Gas sensors; Gold; Grain size; Metals; Methods; Methylene blue; Nanocrystals; Nanoparticles; Noble metals; Optical properties; Oxytetracycline; photoactive; Photocatalysis; Photovoltaic cells; Physical characteristics; Physical properties; Physicians; Pollutants; Quantum dots; Semiconductor materials; Semiconductors; Structure; Thick films; Thin films; X-ray diffraction; X-rays; Zinc oxide; Zinc oxides; ZnO quantum dots
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28124644

Nanoscale ZnO is a vital semiconductor material whose versatility can be enhanced by sensitizing it with metals, especially noble metals, such as gold (Au). ZnO quantum dots were prepared via a simple co-precipitation technique using 2-methoxy ethanol as the solvent and KOH as the pH regulator for hydrolysis. The synthesized ZnO quantum dots were deposited onto glass slides using a simple doctor blade technique. Subsequently, the films were decorated with gold nanoparticles of different sizes using a drop-casting method. The resultant films were characterized via various strategies to obtain structural, optical, morphological, and particle size information. The X-ray diffraction (XRD) reveals the formation of the hexagonal crystal structure of ZnO. Upon Au nanoparticles loading, peaks due to gold are also observed. The optical properties study shows a slight change in the band gap due to Au loading. Nanoscale sizes of particles have been confirmed through electron microscope studies. P.L. studies display blue and blue-green band emissions. The significant degradation efficiency of 90.2% methylene blue (M.B.) was attained in natural pH in 120 min using pure ZnO catalyst while one drop gold-loaded catalysts, ZnO: Au 5 nm, ZnO: Au 7 nm, ZnO: Au 10 nm and ZnO: Au 15 nm, delivered M.B. degradation efficiency of 74.5% (in 245 min), 63.8% (240 min), 49.6% (240 min) and 34.0% (170 min) in natural pH, respectively. Such films can be helpful in conventional catalysis, photocatalysis, gas sensing, biosensing, and photoactive applications.