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Polydimethylsiloxane: Optical properties from 191 to 1688?nm (0.735–6.491?eV) of the liquid material by spectroscopic ellipsometry
摘要： Polydimethylsiloxane (PDMS) is an important polymer with numerous applications. Herein, the authors report the optical function(s) of PDMS from 191 to 1688 nm as determined from reflection spectroscopic ellipsometry (SE) and transmission ultraviolet-visible data. Two commercial samples of liquid PDMS (PDMS700 and PDMS2000) with molecular weights of 700–1500 g/mol and 2000–3500 g/mol, respectively, were analyzed. Both samples were linear polymers terminated with silanol groups. The optical functions determined from the two materials were essentially identical. Both the reflection and transmission measurements obtained from these materials required special experimental considerations. For the reflection SE measurements, these included roughening (frosting) the inside of the vessel that held PDMS and the need to level the instrument instead of the samples. The transmission measurements were obtained via a dual cuvette approach that eliminated the effects of the cuvettes and their interfaces. In addition to analyzing the data from the individual samples, the SE data from the samples were considered together in a multisample analysis (MSA). Because both samples of PDMS were transparent over the measured wavelength range, and because of the relatively wide wavelength range considered, the optical functions here were fit with Sellmeier models. This produced a good fit for the MSA with a mean squared error value of 1.68. The optical functions obtained in this work agreed well with previously reported values. For example, for the MSA, the authors obtained the following nx values, where x is the wavelength in nanometers: n300 = 1.443, n500 = 1.407, and n1000 = 1.393.
关键词： spectroscopic ellipsometry,optical properties,Sellmeier,transmission,optical function,polydimethylsiloxane (PDMS)
更新于2025-09-23 15:22:29
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Miniaturized Planar Sensor Development
摘要： This paper describes the process of developing a miniature device with planar sensors utilizing electrical capacitance measurement. The project investigates the feasibility and characterization of a miniaturized planar sensor integrated on a polydimethylsiloxane (PDMS) chamber. A 16-planar-electrodes array, with each dimension of the electrode, 4 mm × 2 mm (length × width) was fabricated using a printed circuit board (PCB) technology due to its low cost advantage. The measurement chamber for the sensing area was fabricated using PDMS. The PDMS chamber was bonded on the PCB with a semi cured PDMS to create a round sensing area for sample loading. The mould to develop the PDMS chamber was designed using AutoCAD 2010 and was fabricated using a 3D printer. Capacitance measurement of the planar electrodes was carried out using water as the sample and was validated using a theoretical calculation. Experimental result shows that the distance of the measured electrodes is inversely proportional to the capacitance value. The range of the measured capacitances of the measurement varies from 10 pF to 20 pF. The result shows that the planar sensors are able to provide capacitance measurement within the miniaturized platform where the measured capacitance showed good agreement with the theoretical calculation.
关键词： printed circuit board (PCB),Planar sensors,capacitance measurement,polydimethylsiloxane (PDMS)
更新于2025-09-23 15:21:21
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Study of solar irradiance and performance analysis of submerged monocrystalline and polycrystalline solar cells
摘要： Underwater photovoltaic (PV) systems supported with modern-day technology can lead to possible solutions for the lack of long-term power sources in marine electronics, navy corps, and many other remotely operated underwater power systems. Currently, most of these systems are powered by conventional batteries, which are bulky, costly, and require periodic maintenance and replacement. Harnessing the underwater Solar energy by using Solar PV cells is simple, reliable, and leads to tremendous advantageous as water itself provides cooling, cleaning, and avoid challenges due to land constraints. The present work encompasses an experimental study on Solar radiation in water and its changes with varying water conditions. Accordingly, the performance of monocrystalline and polycrystalline silicon solar cells with different submerged water conditions and water depths up to 20 cm has been studied. Most importantly, these studies have been carried out with different types of water conditions, consisting of salinity, bacteria, algae, and other water impurities. These investigation results manifest that the percentage decrease of maximum power output in monocrystalline and polycrystalline Solar cells is 65.85% and 62.55%, respectively, in the case of ocean water conditions, whereas in deionized (DI) water conditions, it is 63.06% and 60.72% up to 20 cm. Such results conclude that valuable amount of Solar energy is can be explored underwater. These experimental studies pave the way to explore further to utilize Solar PV cells efficiently in underwater conditions.
关键词： monocrystalline Solar cell,underwater Solar radiation,photovoltaic (PV) technology,PDMS (polydimethylsiloxane),water salinity,polycrystalline Solar cell
更新于2025-09-23 15:21:01
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Flexible Capacitive Pressure Sensor Based on PDMS Substrate and Ga-In Liquid Metal
摘要： A novel flexible pressure sensor, based on polydimethylsiloxane (PDMS) and eutectic gallium indium (EGaIn) liquid metal, was developed for detecting various applied pressures. The sensor was fabricated with PDMS polymer based electrode channels that are filled with EGaIn liquid metal. The liquid metal based electrodes were designed to form four capacitors (C1, C2, C3 and C4). Conventional PCB technology was used to manufacture the master mold to form the PDMS based electrode channels. Corona discharge treatment was employed to bond the PDMS layers at room temperature, under atmospheric pressure. The capability of the fabricated pressure sensor was demonstrated by investigating the capacitive based response of the device for varying applied pressures. Average capacitance changes ranging from 2.3% to 12.0%, 2.6% to 11.8%, 2.5% to 12.2% and 2.7% to 13.1% when compared to the based capacitance of 14.1 pF, 15.1 pF, 13.8 pF and 13.3 pF was obtained for C1, C2, C3 and C4, respectively, for applied pressures ranging from 0.25 MPa to 1.10 MPa. A linear relationship was obtained for the average capacitance change with a sensitivity of 0.11%/MPa, and a correlation coefficient of 0.9975. The results obtained thus demonstrate the feasibility of employing liquid metal based electrodes for the fabrication of flexible pressure sensing devices.
关键词： Corona treatment,Polydimethylsiloxane (PDMS),Eutectic Gallium - Indium (EGaIn),Printed circuit board (PCB),Pressure Sensor
更新于2025-09-23 15:21:01
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Shaping Metallic Nanolattices: Design by Microcontact Printing from Wrinkled Stamps
摘要： A method for the fabrication of well-defined metallic nanostructures is presented here in a simple and straightforward fashion. As an alternative to lithographic techniques, this routine employs microcontact printing utilizing wrinkled stamps, which are prepared from polydimethylsiloxane (PDMS), and includes the formation of hydrophobic stripe patterns on a substrate via the transfer of oligomeric PDMS. Subsequent backfilling of the interspaces between these stripes with a hydroxyl-functional poly(2-vinyl pyridine) then provides the basic pattern for the deposition of citrate-stabilized gold nanoparticles promoted by electrostatic interaction. The resulting metallic nanostripes can be further customized by peeling off particles in a second microcontact printing step, which employs poly(ethylene imine) surface-decorated wrinkled stamps, to form nanolattices. Due to the independent adjustability of the period dimensions of the wrinkled stamps and stamp orientation with respect to the substrate, particle arrays on the (sub)micro-scale with various kinds of geometries are accessible in a straightforward fashion. This work provides an alternative, cost-effective, and scalable surface-patterning technique to fabricate nanolattice structures applicable to multiple types of functional nanoparticles. Being a top-down method, this process could be readily implemented into, e.g., the fabrication of optical and sensing devices on a large scale.
关键词： metallic nanolattices,oligomeric polydimethylsiloxane,microcontact printing,hydroxyl-functional poly(2-vinyl pyridine),gold,wrinkled stamps,nanoparticle assembly,polydimethylsiloxane wrinkles
更新于2025-09-23 15:19:57
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Analysing consequence of solar irradiance on amorphous silicon solar cell in variable underwater environments
摘要： Harvesting underwater Solar energy using photovoltaic (PV) technology leads to an innovative approach to utilize it in monitoring various underwater sensors, devices, or other autonomous systems using modern-day power electronics. Another huge advantage of placing PV cells underwater comes from the fact that the water itself can provide cooling and cleaning for the cells. Such advantages come with many challenges and constraints due to the underwater spectral change and decrease in Solar radiation with an increase in water depth. In this work, an experimental set-up has been realized to create an underwater environment and further characterized in the indoor environment using the Solar simulator. Moreover, the transfer of Solar radiation through water and the performance of amorphous silicon Solar cell underwater up to 0.2 m has been analysed in changing underwater environments. This investigation shows a better understanding of solar radiation underwater and the amorphous silicon solar cell underwater at shallow depths with considering the water depth up to 0.2 m, salinity 3.5%, total dissolved salts, and other impurities affecting the solar radiation and the performance of amorphous silicon Solar cell in underwater conditions. In addition to that, the maximum power output Pmax of amorphous silicon Solar cell is 0.0367 W at 0.2 m in the case of DI water. In contrast, in real seawater and artificial seawater with 3.5% salinity, it shows 0.0337 W and 0.0327 W, respectively.
关键词： water salinity,amorphous silicon Solar cell,photovoltaic (PV) technology,underwater Solar energy,Solar radiation,PDMS (polydimethylsiloxane)
更新于2025-09-23 15:19:57
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Omni-direction PERC solar cells harnessing periodic locally focused light incident through patterned PDMS encapsulation
摘要： Photovoltaic panels based on crystalline Si solar cells are the most widely utilized renewable source of electricity, and there has been a significant effort to produce panels with a higher energy conversion efficiency. Typically, these developments have focused on cell-level device modifications to restrict the recombination of photo-generated charge carriers, and concepts such as back surface field, passivated emitter and rear contact (PERC), interdigitated back contact, and heterojunction with intrinsic thin layer solar cells have been established. Here, we propose quasi-Fermi level control using periodic local focusing of incident light by encapsulation with polydimethylsiloxane to improve the performance of solar cells at the module-level; such improvements can complement cell-level enhancements. Locally focused incident light is used to modify the internal quasi-Fermi level of PERC solar cells owing to the localized photon distribution within the cell. Control of the local focusing conditions induces different quasi-Fermi levels, and therefore results in different efficiency changes. For example, central focusing between fingers enhances the current density with a reduced fill factor, whereas multiple local focusing enhances the fill factor rather than the current density. Here, these effects were explored for various angles of incidence, and the total electrical energy production was increased by 3.6% in comparison to a bare cell. This increase is significant as conventional ethylene vinyl acetate-based encapsulation reduces the efficiency as short-wavelength light is attenuated. However, this implies that additional module-scale studies are required to optimize local focusing methods and their synergy with device-level modifications to produce advanced photovoltaics.
关键词： quasi-Fermi level control,module-level enhancements,energy conversion efficiency,Photovoltaic panels,crystalline Si solar cells,local focusing,polydimethylsiloxane,PERC solar cells
更新于2025-09-23 15:19:57
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IR ns pulsed laser irradiation of Polydimethylsiloxane in vacuum
摘要： Polydimethylsiloxane (PDMS) has been irradiated by a ns pulsed IR laser in vacuum and the radiation effects induced by the coherent radiation, above a threshold fluence, produce a non-equilibrium plasma and material ablation. The laser absorption can be enhanced using gold nanoparticles (AuNPs) embedded in the polymer. The laser-generated plasma has been characterized, whereas the ion emission from both the virgin PDMS and the PDMS t AuNPs sheets has been analysed both in mass and energy. Morphological investigations, optical spectroscopy and compositional analyses have been performed. The adopted laser treatment can be employed to modify the properties of PDMS with and without AuNPs inducing a local enrichment of microcrystalline silicon in both cases.
关键词： Laser ablation,PDMS,TOF,Laser-generated plasma,Polydimethylsiloxane
更新于2025-09-19 17:13:59
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Laser-Assisted Fabrication of a Highly Sensitive and Flexible Micro Pyramid-Structured Pressure Sensor for E-Skin Applications
摘要： A novel capacitive pressure sensor based on micro-structured polydimethylsiloxane (PDMS) dielectric layer was developed for wearable E-skin and touch sensing applications. The pressure sensor was fabricated on a flexible polyethylene terephthalate (PET) substrate, using PDMS and silver (Ag) as the dielectric and electrode layers, respectively. A set of PDMS films with pyramid shaped micro-structures were fabricated using a laser engraved acrylic mold. The electrodes (top and bottom) were fabricated by depositing Ag on PET films using additive screen-printing process. The pressure sensor was assembled by attaching the top and bottom Ag electrodes to the smooth side of pyramid shaped micro-structured PDMS (PM-PDMS) films. The top PM-PDMS was then placed on the bottom PM-PDMS. The capability of the fabricated pressure sensor was investigated by subjecting the sensor to pressures ranging from 0 to 10 kPa. A sensitivity of 0.221% Pa-1, 0.033% Pa-1 and 0.011% Pa-1 along with a correlation coefficient of 0.9536, 0.9586 and 0.9826 was obtained for the pressure sensor in the pressure range of 0 Pa to 100 Pa, 100 Pa to 1000 Pa, and 1 kPa to 10 kPa, respectively. The pressure sensor also possesses a fast response time of 50 ms, low hysteresis of 0.7%, recovery time of 150 ms and excellent cycling stability over 1000 cycles. The results demonstrated the efficient detection of pressure generated from various activities such as hand gesture and carotid pulse measurement. The PM-PDMS based pressure sensor offers a simple and cost-effective approach to monitor pressure in E-skin applications.
关键词： E-skin,Laser patterning,Pressure sensor,Micro-pyramid structure,Polydimethylsiloxane (PDMS),Screen printing process,Polyethylene terephthalate (PET)
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - In-fiber Surface Plasmon Resonance Temperature Sensor Based on PDMS Infiltrated Hollow Core Fiber
摘要： An in-fiber surface plasmon resonance temperature sensor based on Polydimethylsiloxane infiltrated hollow core fiber was experimentally proposed and demonstrated. Results demonstrated that the proposed sensor behaved high sensitivity of -1.05nm/℃, small size, and good stability.
关键词： Surface plasmon resonance,Hollow core fiber,Polydimethylsiloxane,Temperature sensor
更新于2025-09-16 10:30:52