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Different Methods and Technologies of Advanced Oxidation Processes Adopted in Industrial Wastewater Treatment
Published in Maulin P. Shah, Wastewater Treatment, 2022
Anitha Thulasisingh, Poojitha Nagapushnam, Yamunadevi Balakrishnan, Sathishkumar Kannaiyan
Semiconductor films and foams can also be synthesized for AOPs. Films can be formed by sol-gel processing, which allows the control of the microstructure of the film. But for the production of TiO2 particles, these may result in changes in crystalline structure and other properties. Thus to overcome this, semiconductor films can be formed by dip coating and spin coating. These methods utilize a much smaller quantity of raw materials and can be processed quickly without cracking. Spin coating can be done for flat substrates or objects, whereas dip coating is done by immersing the substrate into the sol and removing it with uniform velocity to achieve a uniform coating over it. Foams can also be formed that have a thickness of range 100–500 nm. They offer more diffusion pathways than that of films.
The Challenge of Realizing Nanothin Perovskite Single-Crystalline Wafers: Computational and Experimental Aspects
Published in Satya Bir Singh, Prabhat Ranjan, A. K. Haghi, Materials Modeling for Macro to Micro/Nano Scale Systems, 2022
M. Pratheek, T. A. Shahul Hameed, P. Predeep
The commonly used deposition techniques, briefed above, like solution processing and thermal evaporation are problematic in that, they directly affect the performance of the coated perovskite layer. Spin coating is preferred over other techniques because it is facile and of low cost. But the major issues of these methods are (1) poor morphology, (2) presence of pin holes, (3) requirement of scaffolding layer, (4) requirement of postannealing, (5) poor reproducibility, and (6) not suitable for large-area devices. A solution to these problems is to develop single-crystalline wafers of perovskite absorbers directly to the transparent anodes coated with transport layers. In the case of silicon solar cells, single-crystalline wafer solar cell show high efficiency and operational stability; however, in silicon technology, single-crystalline wafer production is rather easy. Wafers of mm size can easily be sliced out of large single-crystalline ingots by sawing. This is feasible just because the diffusion length of charge carriers in silicon is in the range of millimeters. However, for perovskites the diffusion length is only few tens of micrometers and therefore needs wafers of thickness around this thickness, which is not possible by slicing out as in the case of silicon wafers.
Oxide whisker growth mechanism of 304 stainless steel coated with hot-dipping pure Al and Si-modified aluminide coating
Published in Artde Donald Kin-Tak Lam, Stephen D. Prior, Siu-Tsen Shen, Sheng-Joue Young, Liang-Wen Ji, Innovation in Design, Communication and Engineering, 2020
The SIGMA D-Sorbitol (98%) doped the Clevios PH 500 PEDOT: PSS was used as solution for preparation of thin films by a spin-coating method. The Sorbitol was added to the PEDOT: PSS directly, and then the doped PEDOT: PSS was stirred for 30 min at room temperature. The mixed solution was doped again by adding different molar concentrations of H2SO4. At last, the mixed PEDOT: PSS solution is the so-called the double doped PEDOT: PSS solution. The double doped PEDOT: PSS solution was coated by spinner on 2 × 2 cm2 glass substrates and formed the double doped PEDOT: PSS film. The glass substrates were pre-cleaned with acetone, methanol and de-ionized (DI) water in an ultrasonic bath, sequentially. The spin-coating was performed at a rotation rate of 3500 rpm for 20 sec. The double doped PEDOT: PSS film was heated at 150 °C for 20 min on a hotplate in ambient lab conditions.
Rapid fabrication of colloidal crystal films by spin coating using polymeric particles synthesized by dispersion polymerization
Published in Particulate Science and Technology, 2023
Thi Thu Hien Nguyen, Hoai Han Nguyen, Young-Seok Kim, Young-Sang Cho
Though dip coating method to create colloidal crystal films on the glass substrate is a simple and convenient way, it is time-consuming manner which requires high-precision apparatus. On the contrary, spin coating method is not only easy to implement but also does not take much time (Moon et al. 2008). The spin coating is a way to deposit a uniform film onto a solid surface by using centrifugal force, by placing any liquid at the center of a substrate and rapidly rotating to produce uniform colloidal crystal layers. The entire process is shown schematically in Figure 1(a). Among the methods of fabricating colloidal crystal films, the spin coating process is convenient to produce functional films with smaller nanoparticle, which can be applied to nanolithography to form plasmonic metamaterials (Zhang, Cvetanovic, and Pearce 2017). The physical properties of colloidal crystal films of PS nanospheres are dependent on processing conditions such as solution quantity, rotation velocity, and spinning time (Jiang et al. 2006; Lubambo et al. 2011; Chen et al. 2013; Banik and Mukherjee 2018).
Dielectric and electro-optical properties of ferric oxide nanoparticles doped 4-octyloxy-4’ cyanobiphenyl liquid crystal-based nanocomposites for advanced display systems
Published in Liquid Crystals, 2021
Pankaj Kumar Tripathi, Aradhana Roy, Abhishek Kumar Misra, Kamal Kumar Pandey, Rajiv Manohar, Y. S. Negi
LC sample cells were prepared by using two indium tin oxide (ITO)-coated glass plates. The required pattern on ITO glass plates were fabricated by photolithography techniques. The thickness of the two ITO glass plates was uniformly sustained by placing a mylar spacer between them. The planar alignment on the striped glass plates was achieved by using regular rubbed polyimide techniques [23]. To obtain the cells with planar and homeotropic alignment, nylon, 6/6 and lecithin were spin coated on the substrate surfaces, respectively. Spin coating was done at 3000 RPM for 30 second. The coated substrates were prebaked at 100°C for 10 minutes on a hot plate and annealed at 180°C for 1 hour. The pristine and Fe2O3 NPs doped LC were filled into 6 µm thick aforementioned cell via capillary action. The structure was then sealed with epoxy, and placed inside an Instec (HCS-302) hot stage with a temperature precision of ±0.1°C. The temperature was adjusted to 80°C and to obtain isotropic phase. The samples cells were then cooled down with a rate of 0.2°C/min in the presence of the electric field. The LC director aligned along the electric field, and structural evolution was investigated systematically while cooling down to 66°C.
Electronic and optoelectronic applications of solution-processed two-dimensional materials
Published in Science and Technology of Advanced Materials, 2019
Compared with layer-by-layer and Langmuir–Blodgett methods, spin coating is a relatively convenient approach for large-scale fabrication of thin films. In this method, 2D materials suspension will be firstly dropped onto a target substrate. Then, a certain rotation speed and time will be used to spread the suspension and prepare a film with equal thickness around all substrate surfaces. Spin-coating method has several advantages like simplicity, fast, and high efficiency. Many 2D materials have been assembled by this method into thin films. For example, Vendamme et al. prepared ultra-thin films of titania (TiO2) and other metal oxides by spin-coating process [38]. Recently, Matsuba et al. developed a one-pot spin-coating method and fabricated dense monolayer thin films made of various 2D materials within 1 min over a very wide area (30-mm-diameter) [39]. The ultra-thin films prepared by spin-coating can be used to fabricate TFT devices. However, if one wants to prepare thick films, it is better to choose other assembly approaches rather than spin-coating, because it is difficult to ensure the uniformity of thick films in spin-coating method which would involve complicated cycling process and dispersion formula.