In this work, a heterostructure-based thin film combining n-type α-Fe 2 O 3 with p-type CuO was fabricated by a dip-coating technique, the heterostructure was fabricated on fluorine-doped tin oxide (FTO) glass substrate. The synthesised sample was characterised by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectroscopy (UV-vis). XRD, FTIR, Raman, and XPS reveal the successful synthesis of α-Fe 2 O 3 /CuO composite and confirm the existence of hematite (α-Fe 2 O 3 ) and tenorite (CuO) phases in the heterostructure. AFM reveals the growth of CuO crystals in the heterostructure with superficial intermingled pointy shape, different than its pristine topography. The SEM images show that the α-Fe 2 O 3 /CuO heterostructure thickness was ∼880 nm. The optical band gap energies estimated from the optical transmittance spectra were 2.15, 2.00 and 1.77 eV for α-Fe 2 O 3 , CuO and α-Fe 2 O 3 /CuO heterostructure, respectively. The photoelectrochemical photocurrent effects (J-V curves) for the heterostructure were measured in a three-electrode cell in the dark and under illumination. The photocurrent density for heterostructure was improved mainly attributed to the enhanced visible light absorption, efficient charge carriers separation and transfer between α-Fe 2 O 3 and CuO.

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In this work, a self-made dip-coater equipment was developed for the fabrication of thin films. The assembly of the apparatus was carried out using simple mechanical and electronic pieces, recycle parts, and spending an inexpensive budget suitably. The production, software design, and features of the device were focused on the sol-gel dip-coating method, which involves gravitational draining and drying processes, as well as continued condensation reactions. The dip-coater was based on the Arduino microcontroller and a step motor. The immersion speed in the solution, the waiting time, and the withdrawal process were typed by a digital control panel, where the optimal range found for speed was 0.1 – 6.0 mm s-1 without vibration interferences. The total fabrication cost of the fabricated dip coater was less than 100 USD and the assembly process was not complicated. Finally, the performance of the dip-coater was evaluated through the deposit of copper oxide and iron oxide films on fluorine-doped tin oxide glass substrates layer by layer. The field emission scanning electron microscopy cross-section images confirm the formation of thin films with thickness in the nanoscale range, with good stability and sameness achieved through the control thickness during the dip-coating method under ambient conditions.

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In this work, self-made laboratory centrifuge equipment was developed for the separation of suspensions and immiscible liquids. This centrifuge was based on the Arduino microcontroller and fabricated from simple and recycled mechanical and electronic parts, spending an inexpensive budget suitably. The centrifuge frame and rotors were manufactured of Polylactic Acid (PLA) filaments, which were printed in a 3D printer. Two rotors labeled R50 and R15 were designed and fabricated to use tubes of 50 mL and 15 mL, respectively. The maximum speed reached, without vibration interferences, was 3350 and 3030 rpm for R50 and R15 rotors, respectively. The total fabrication cost of the fabricated centrifuge was less than 100 USD and the assembly process was not complicated. Finally, the centrifuge performance was evaluated through phases of separation of precipitate of CuCO3(s) and clinical blood samples. The obtained results showed achievement in components separation, entirely comparable with those obtained employing a commercial centrifuge.