An embedded system-based spin coating machine has been developed to grow thin films. Pure zinc oxide (ZnO) and magnesium-doped zinc oxide (ZnO: Mg) thin films with different doped samples have been prepared using the spin coating technique for LPG gas sensing application. The spin coating machine is fully controlled by a PIC microcontroller (PIC16f877A), which can drive a driver circuit to drive a spinning motor, and ZnO: Mg thin films are deposited using this machine. XRD results indicated that the movie has a hexagonal wurtzite structure with a preferred orientation, and the crystallite size increases with the increasing doping concentration of Mg. The surface morphology investigation shows that grains are irregular in shape, and doping concentrations do not influence the surface morphology. From the TEM image, particle sizes observed ranged between 23 and 28 nm, with an average value of ~25.8 nm. The maximum visible average transmittance was 96% for an optimum Mg doping concentration of 10 wt% %. The investigated DC electrical conductivity of Mg-doped ZnO thin films shows enhanced electrical conductivity compared to pure ZnO, and the AC conductivity is decreased with increasing Mg doping concentrations from 5 to 10 wt%. The operation and sensing mechanism of Pure ZnO and ZnO: Mg thin films behind their impressive results has been studied in depth.

Thin Film Transistors (TFTs) are increasingly prevalent electrical components in display products, ranging from smartphones to diagonal flat panel TVs. The limitations in existing TFT technologies, such as high-temperature processing, carrier mobility, lower ON/OFF ratio, device mobility, and thermal stability, result in the search for new semiconductor materials with superior properties. The main objective of this present work is to fabrícate the efficient Single-Walled Carbon Nanotube Thin Film Transistor (TFT) for flat panel display. Carbon Nano-Tubes (CNTs) are a promising semiconductor material for TFT devices due to their one-dimensional structure and exceptional characteristics. In this research work, the CNTTFTs have been fabricated using nano-fabrication techniques with a spin process. The fabricated devices have been characterized for structural, morphological, and electrical characteristics. The 20 μm channel length and 30 μm channel width fabricated device produces about 1.3 nA, which lies in the practical range of operating TFTs reported previously. Compared to reported patents and published works, this demonstrates a significant improvement. Further guidelines and limitations of this fabrication method are also discussed for future efficient device fabrication.

A broadband photodetector based on an Al/ZnO/WSe<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>: PCBM/Poly-TPD/ITO coated PET structure is proposed in this article. The Indium tin oxide (ITO) and Aluminum (Al) work as electrodes, WSe<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>: PCBM bulk heterojunction (BHJ) behaves as an active layer, while Poly-TPD and ZnO are utilized as HTL (hole transport layer) and ETL (electron transport layer) in the proposed photodetector. The low-cost dispersion technique and spin coater equipment is utilized for solution preparation and film deposition. The Al electrodes were deposited using shadow masking approach in a thermal evaporation unit. The proposed BHJ based photodetector displays maximum responsivity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{R}_S}$</tex-math></inline-formula>(A/W) of 2035 A/W, 2048 A/W, and 1833 A/W; at 300nm (UV), 450nm (visible) and 1300nm (NIR) at -1V bias. The interfacial layers ETL and HTL inclusion exhibits improved device performance and paves the way for the optoelectronic and real time applications.

The photolithographic patterning of heavy-metal-free InP quantum dots (QDs) is of significance for applications in high-resolution displays. Light-driven direct cross-linking of ligands from adjacent QDs, without introducing insulating photoresist, is a feasible strategy. Nonetheless, the randomly arranged, loosely stacked QDs generated by traditional deposition present significant interstitial voids, which hinder the effective cross-linking of ligands. In this study, close-packed monolayer InP QDs are assembled utilizing Langmuir-Blodgett (LB) technology to facilitate robust cross-linking. The QDs arranged side by side, followed by the photo-cross-linking process, demonstrate superior resistance to the developing process compared to those derived from spin-coated (SC) films. InP QD light-emitting diodes (QLEDs) with finely patterned pixels (average size of 3 μm × 3 μm) have been successfully fabricated, achieving a resolution exceeding 4000 pixels per inch. Additionally, the patterned monolayer QLEDs exhibit a high external quantum efficiency of 9.56%, considerably outperforming those of SC-based devices (4.99%). This work presents a promising approach for the lithographic fabrication of environment-friendly QLEDs.

As a great chelating agent, Coiandrum Sativum extract was used in the biosynthesis of NiO nanoparticles, which was an environmentally friendly process. The nanoparticles were then investigated by x-ray diffraction, FT-IR, and SEM. The result of SEM suggests that the nanoparticles have some agglomeration but are primarily spherical. After that, powdered nano-particles were used to make thin films, which were annealed for 60 minutes at (300 and 400) °C in the air. Atomic force microscopy (AFM) and X-ray diffraction (XRD) were utilized to determine the structural properties and composition of nickel oxide films, the films’ surfaces are smooth and that the crystalline geometry of the films is cubic. Following annealing at 400 °C, the nickel oxide layer’s surface profile is composed of uniformly sized ultrafine grains. The grain size increases from 39 to 46 nm with increasing the annealing temperature of the thin layer.

Octachlorinated metal phthalocyanines (MPcCl8, M = Co, Zn, VO) represent an underexplored class of functional materials with promising potential for chemiresistive sensing applications. This work is the first to determine the structure of single crystals of CoPcCl8, revealing a triclinic (P-1) packing motif with cofacial molecular stacks and an interplanar distance of 3.381 Å. Powder XRD, vibrational spectroscopy, and elemental analysis confirm phase purity and isostructurality between CoPcCl8 and ZnPcCl8, while VOPcCl8 adopts a tetragonal arrangement similar to its tetrachlorinated analogue. Thin films were fabricated via physical vapor deposition (PVD) and spin-coating (SC), with SC yielding highly crystalline films and PVD resulting in poorly crystalline or amorphous layers. Electrical measurements demonstrate that SC films exhibit n-type semiconducting behavior with conductivities 2-3 orders of magnitude higher than PVD films. Density functional theory (DFT) calculations corroborate the experimental findings, predicting band gaps of 1.19 eV (Co), 1.11 eV (Zn), and 0.78 eV (VO), with Fermi levels positioned near the conduction band, which is consistent with n-type character. Chemiresistive sensing tests reveal that SC-deposited MPcCl8 films respond reversibly and selectively to ammonia (NH3) and hydrogen sulfide (H2S) at room temperature. ZnPcCl8 shows the highest NH3 response (45.3% to 10 ppm), while CoPcCl8 exhibits superior sensitivity to H2S (LOD = 0.3 ppm). These results suggest that the films of octachlorinated phthalocyanines produced by the SC method are highly sensitive materials for gas sensors designed to detect toxic and corrosive gases.

This article demonstrates a broadband photodetector based on a ITO/Poly-TPD/WSe<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>: MXene/PCBM/Al architecture. The dispersion method prepared Poly-TPD (PTPD) and PCBM functions as hole transport layer (HTL) and electron transport layer (ETL) while WSe<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>: MXene nanocomposite (NC) serves as the active layer in the device. The film deposition is executed using spin coater whereas Al electrode deposition is performed in thermal evaporation chamber using shadow masking approach. At 350 nm (UV), 400 nm (visible), and 1450 nm (IR), the suggested photodetector shows maximum responsivity (A/W) of 2354, 2425, and 736.7 for -1V bias at a fixed optical power of 0.118 μW. The interfacial layers (ETL/HTL) and WSe<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>: MXene nanocomposite shows promising characteristic for the use in optoelectronic applications.

Sol-gel Spin Coating method for thin film deposition

This study investigates the structural and optical properties of zinc oxide thin films doped with 1% bismuth (Bi₀.₀₁Zn₀.₉₉O) and antimony (Sb₀.₀₁Zn₀.₉₉O), fabricated using the sol-gel spin coating technique. The influence of Bi and Sb incorporation on the morphological and optical behavior of ZnO nanostructures was systematically examined through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDAX), and UV-Vis spectrophotometry. XRD analysis confirmed that all films retained a hexagonal wurtzite structure with preferential orientation along the (002) plane. The introduction of dopants significantly reduced the average crystallite size from 33.3 nm in pure ZnO to 12.42 nm for Bi-doped and 14.097 nm for Sb-doped films, indicating inhibition of crystal growth along the c-axis. FESEM images revealed uniform, densely packed nanostructures with oval-shaped grains and the formation of nanorods in Bi-doped samples. Optical characterization demonstrated high visible-range transmittance, reaching 91.58% for Sb-doped films, compared to 80.63% for Bi-doped films. The optical bandgap increased from 3.217 eV for Bi-doped ZnO to 3.314 eV for Sb-doped ZnO. These findings underscore the potential of Bi and Sb-doped ZnO thin films as promising transparent conducting oxides for use in optoelectronic and electronic device applications.

The article presents the results of structural, corrosion, microbiological, biological, and genotoxicity studies on the effect of graphene oxide deposited on a flat titanium foil surface, intended for use, in general, implantology and other medical applications. The methodology of graphene oxide (GO) deposition involved a surface cleaning process combined with RF plasma activation, followed by the application of a thin layer of dispersed aqueous GO suspension using a spin coater. The graphene oxide layer was uniformly deposited on the surface, which was confirmed by SEM imaging. Corrosion studies were carried out in an electrochemical cell filled with a buffered solution prepared to mimic the composition of physiological intracellular fluids. It was demonstrated that the deposition of graphene oxide on the titanium surface limited the access of electrolyte and oxygen. Surface activation and deposition of the aqueous graphene oxide suspension contributed to improved adhesion, condition, growth, and proliferation of fibroblast cell lines Hs 895.T and Hs 895.Sk. The inhibition zone analysis revealed a bacteriostatic effect against Pseudomonas aeruginosa and Staphylococcus aureus. Moreover, no genotoxicity changes were observed.

ABSTRACT Perovskite solar cells often exhibit performance variability even under identical experimental conditions. One of the reasons of this inconsistency is attributed to manual interventions such as the application of antisolvents. To address these challenges, we develop an automated system to precisely control the solvent dropping and substrate heating processes. Spin‐coating is performed by using an automated system comprising a robot arm, spin coater, automatic solution dropping part, hot plate, and substrate storage area. Manual fabrication is conducted simultaneously to compare the outcomes. The reproducibility of devices fabricated by using the system and intrabatch and interbatch consistency are assessed. The automated system considerably diminishes performance fluctuations across batches conducted on different dates. Especially, the automated, uniform application of an antisolvent considerably minimizes surface roughness variability in perovskite films. X‐ray diffraction analyses further reveal differences between the residual PbI 2 contents of perovskite films fabricated via automated and manual methods. Additionally, grazing incidence wide‐angle X‐ray scattering measurements indicate that the residual PbI 2 depth distribution in the perovskite layer was influenced by the antisolvent drop rate and timing. The results suggest that precise control of antisolvent drop rates and drop timings can improve the reproducibility of perovskite solar cells.

This work presents a study on the fabrication of polymethyl methacrylate (PMMA) coatings on NiTi alloys using the spin-coating technique, combining numerical simulation with COMSOL Multiphysics 6.3 and experimental validation. This study provides a numerical framework and parametric study of a COMSOL-based simulation framework for estimating the PMMA coating thickness during the spin-coating process. We present an axisymmetric numerical framework, consistent with classical analytical trends; we provide parametric maps (viscosity, rpm, volume) to delimit thickness ranges (e.g., 100–300 μm). Limitations with no experimental validation are included and evaporation is not modeled; therefore, the figures are indicative estimates. The spin-coating parameters, such as the rotation speed, internal pressure, viscosity of the PMMA solution, and initial volume of the polymer solution, are considered important factors for the simulation process. The coating parameters determine the thickness of the coating layer achieved during the process of spin coating. The 2D axisymmetric flow considers internal factors of a surface tension of 0.07 N·m, a contact angle of 90°, and a density of 1150 kg/m3 for the coating process without evaporation effects. The moving mesh (coating layer) is considered a free surface without any slip boundary with the substrate surface. The coating thickness was determined by various rotations and dynamic viscosities, using a simulation method. The experimental findings and simulation output of the coating thickness as a function of various dynamic viscosities and rotations match well. The final coating thickness ranged from 100 to 300 μm, depending on a viscosity of 11 mPa·s and 100, 500 rpm.

A cost‐effective, thin‐film spin‐coating method for homogeneous matrix deposition in matrix‐assisted laser desorption/ionization mass spectrometry imaging (MALDI‐MSI) is presented. In this method, the matrix solution is nebulized directly onto the sample surface during continuous rotation in the spin coater, enabling simultaneous spraying and centrifugal spreading for uniform film formation. Although spin coating produces highly uniform matrix layers, its widespread adoption in MALDI‐MSI is hindered by the high cost of commercial instruments. To address this limitation, an in‐house spin coater is developed and optimized. A fractional factorial design identified flow rate, matrix volume, and rotation speed as the most critical parameters for achieving uniform deposition. Under optimal conditions (60 psi, 10 µL·min −1 , 400 µL, and 10 cm at 35 a.u.), the system produces homogeneous matrix films across entire glass slides. The effectiveness of this integrated spray during spin method is demonstrated by imaging the distinct spatial distributions of key lipids and metabolites in mouse brain, strawberry, and carrot tissues. This work establishes the in‐house spin coater as a feasible and robust tool for enhancing reproducibility and data quality in routine MALDI‐MSI workflows.

The technology of surface acoustic wave-based (SAW) sensors greatly depends on the performance of the resulting sensing layer. To ensure real applications, the sensors must be produced with reproducibility, as well as the statistical consistency of analytical sensor response results must be assured. In this work, we investigated the reproducibility and the statistical performance of the coating procedure used in previous works for the development of new polymeric coating materials, and the statistics of the respective sensor responses were analyzed. The polylaurylmethacrilate (PLMA) is used as an example of polymeric coating material. Two series of sensors coated with distinct quantities of the polymer were produced and analyzed. The statistical analysis of the ultrasonic parameters of the sensor production presented very low variability for both series of sensors. The respective sensor responses, obtained with a set of analytes with distinct chemical functions, presented, in the same way, excellent reproducibility for both series of sensors. The very good reproducibility and statistical robustness of the sensor production data and of the respective sensor responses confirm the reliability of the methodology to produce sensors for the SAW technology.

Abstract Adhesion behavior is a primary consideration when applying a coating to any substrate material. Polymer coatings have been applied to glass for enhanced surface properties and protection. Several research studies have been performed on how the solvent used affects the coating properties such as glass transition temperature, relaxation behavior, and surface morphology. While multiple experiments have been conducted to investigate the solvent effect on polymer adhesion to various substrate materials, research has not yet been substantially conducted using glass as the substrate material. Here, the effect of various solvents on poly (methyl methacrylate) (PMMA) adhesion to soda lime silicate glass is investigated. PMMA is dissolved in four different solvents, acetone, butyl acetate, ethyl acetate, and toluene and coated onto 20 × 20 mm2 glass substrates via spin coating. Four different methods for measuring coating thickness are explored including ellipsometry, profilometry, atomic force microscopy (AFM), and scanning electron microscopy (SEM). Adhesion is assessed qualitatively via the tape test, ASTM D3359-23. Thickness data showed conclusive proof that the spin coatings were nonuniform. Ultimately, results from the tape test show a solvent effect on PMMA adhesion to glass, establishing toluene to be the strongest out of the four for adhesion. Recommendations for experimental testing and characterization methods are presented.

This paper reports improvements made to the performance of single-walled carbon nanotube (SWNT) electrodes by integrating a glycerol-doped PEDOT:PSS (PEGL) layer, resulting in a novel material termed SWGL. The PEGL layer addresses key challenges in SWNT electrodes, including poor adhesion, low work function, and limited catalytic activity, by acting as an adhesive interface, carrier injection layer, and catalyst. Through a series of spin-coating and rinsing processes, SWGL films are prepared, exhibiting significantly improved adhesion to inorganic substrates, enhanced electrical conductivity, and stability under thermal treatment. The electronic structure, morphology, and performance of the SWGL films are characterized using techniques such as X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and scanning electron microscopy, revealing a gradual improvement in conductivity and work function with successive SWNT spin coatings. Optimized SWGL electrodes are evaluated by employing them in organic thin-film transistors (OTFTs) and dye-sensitized solar cells (DSSCs), which show substantial improvements in device performance. Specifically, SWGL-based electrodes exhibit excellent charge injection, reduced interface resistance, and comparable efficiency to conventional electrodes used in OTFTs or DSSCs. This work provides a versatile and cost-effective solution for the development of high-performance SWNT-based electrodes for use in diverse electronic devices.

Herein, Cu 2 BaSnSe 4 (CBTSe) thin films are fabricated via a two‐stage process combining spin coating and thermal evaporation, followed by rapid thermal annealing at selenization temperatures of 525, 550, and 575 °C. Cu–Ba–Sn precursor films are prepared by spin coating, and a Se‐cap layer is deposited by thermal evaporation. Structural, optical, and electrical properties are investigated using X‐ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), energy‐dispersive X‐ray spectroscopy, photoluminescence (PL), and Van der Pauw measurements. XRD confirms the formation of the hexagonal CBTSe phase, with the largest crystallite size (≈78 nm) at 575 °C. Minor SnSe and Ba–Sn–O secondary phases are also detected. SEM reveals dense polycrystalline structures with grain growth at higher temperatures. Surface morphology analysis shows that roughness increases from 34.90 nm (525 °C) to 84.30 nm (575 °C), consistent with SEM observations and literature trends indicating grain coarsening at higher annealing temperatures. PL spectra exhibit emission near 1.91–1.93 eV. All films display p‐type conductivity with carrier concentrations around 10 16 cm −3 . Among the investigated samples, the film selenized at 575 °C demonstrates superior crystallinity, enhances optical absorption, increases roughness, and improves electrical performance, making it a promising candidate for high‐efficiency solar cell applications.

A Numerical Study on PV Performance of the Modeled Solar Cell Based on Y-doped CuO Thin Film Produced by Spin Coating

ABSTRACT Lanthanide‐doped upconversion nanoparticles (UCNPs) exhibit unique luminescence properties, making them promising for applications in displays, sensors, security labels, and solar cells. Embedding UCNPs in polymer films can enhance their functionality; however, the properties of the polymer matrix significantly influence the dispersion and loading capacity of UCNPs, ultimately affecting optical performance. In this study, we investigate the incorporation of UCNPs into two distinct polymer matrices, poly(3‐hexylthiophene) (P3HT) and poly(methyl methacrylate) (PMMA), via spin coating at different speeds. Our findings demonstrate that UCNP dispersion and monodispersity are governed by polymer polarity, viscosity, and UCNP concentration in the suspension. To enhance UCNP loading, multiple spin coatings were explored. In UCNP−P3HT films, the volume fraction of UCNPs increased from 26.1% to 51.4% after three consecutive spin coatings, while maintaining a uniform distribution. In contrast, the lower miscibility and higher viscosity of PMMA restricted UCNP loading to 12.0% before significant clustering occurred. Although multiple spin coatings increased the total UCNP content in PMMA films, the volume fraction decreased to 8.0% due to film thickening. This comparative analysis highlights the critical role of polymer matrix properties in UCNP embedding and provides valuable insights for optimizing UCNP−polymer composites for advanced optical applications.

Abstract In this study, spray coating and spin coating methods for the titanium oxide (TiO2) layer used as the electron transfer layer (ETL) were compared to examine the performance parameters of organic solar cells. Despite the fact that there is no major change in the V OC value, with V OC measured at 0.589 V for the spray-coated device and 0.548 V for the spin-coated device, the device performance parameters of the device fabricated with TiO2 layer sharply increased, with the current density–voltage (J–V SC), fill factor (FF), and power conversion efficiency (PCE) values obtained by the spray coating method. We demonstrate that spray-coated c-TiO2 layers achieve a higher PCE of 2.92% compared to 2.32% for spin-coated devices. The PCE of the solar cell using TiO2 formed by spray coating is 25% higher than the device obtained by spin coating.