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Possible application of mixed (thick/thin film) thermopiles to supply autonomous microsystems.

PdAg/AG or PdAg/TSG thermocouples were deposited onto a circular alumina or LTCC substrates. Their thermoelectric power, resistance as well as output electrical power were characterized vs temperature gradient and chosen parameters of thermopile fabrication process.

Semiconductors have high Seebeck coefficient, so investigated kind of thermopile has high output electrical power E_T. It achieves 50 mV per single junction for temperature difference of about 200°C.

The problem is very high resistivity of germanium alloys, even after burn‐in process. Therefore output electrical power P is seriously reduced. To improve thermocouples properties, optimization process is required. For example, thin film layers quality can be improved, semiconductive arms width can be increased or shorter arms can be used.

Application of mixed thick/thin film technology for fabrication of miniaturized thermoelectric generators.

In the past several years, CH₃NH₃PbI₃ perovskite material has been extensively evaluated as an absorber layer of perovskite solar cells due to its excellent structural and optical properties, and greater than 22% conversion efficiency. However, improvement and future commercialization of solar cells based on CH₃NH₃PbI₃ encountered restrictions due to toxicity and instability of the lead element. Recently, studies on properties of lead-free and mixture of lead with other cations perovskite thin films as light absorber materials have been reported. The purpose of this paper was the fabrication of CH₃NH₃Sn₁-xPbxI₃ thin films with different SnI₂ concentrations in ambient condition, and study on the structural, morphological, optical, and photovoltaic performance of the studied solar cells. The X-ray diffraction studies revealed the formation of both CH₃NH₃PbI₃ and CH₃NH₃SnI₃ phases with increasing the Sn concentration, and improvement in crystallinity and morphology was also observed. All perovskite layers had a relatively high absorption coefficient >104 cm⁻¹ in the visible wavelengths, and the bandgap values varied in the range from 1.46 to 1.63 eV. Perovskite solar cells based on these thin films have been fabricated, and device performance was investigated. Results showed that photo-conversion efficiency (PCE) for the pure CH₃NH₃PbI₃sample was 1.20%. With adding SnI₂, PCE was increased to 4.48%.

In this work, the author mixed tin and lead with different percentages in the perovskite thin film. Also, the preparation of these layers and also other layers to fabricate solar cells based on them were conducted in an open and non-glove box environment. Finally, the effect of [Sn/Pb] ratio in the CH₃NH₃Sn₁-xPbxI₃ layers on the structural, morphological, optical, electrical and photovoltaic performance have been investigated.

CH₃NH₃Sn₁-xPbxI₃ (x = 0.0, 0.25, 0.50, 0.75, 1.0) perovskite thin films have been grown by a spin-coating technique. It was found that as tin concentration increases, the X-ray diffraction and FESEM images studies revealed the formation of both CH₃NH₃PbI₃ and CH₃NH₃SnI₃ phases, and improvement in crystallinity, and morphology; all thin films had high absorption coefficient values close to 104 cm⁻¹ in the visible region, and the direct optical bandgap in the layers decreases from 1.63 eV in pure CH₃NH₃SnI₃ to 1.46 eV for CH₃NH₃Sn0.0.25Pb0.75I3 samples; all thin films had p-type conductivity, and mobility and carrier density increased; perovskite solar cells based on these thin films have been fabricated, and device performance was investigated. Results showed that photo-conversion efficiency (PCE) for the pure CH₃NH₃PbI₃sample was 1.20%. With adding SnI2, PCE was increased to 4.48%.

The preparation method seems to be interesting as it is in an ambient environment without the protection of nitrogen or argon gas.

The purpose of this paper is to focus on the technology and performance of the miniature microfluidic module for urea determination. The presented module was made using low-temperature co-fired ceramics (LTCC). It shows the possibility for the integration of the bioreceptor layers with structures that have been fabricated using modern microelectronic technology.

The presented microfluidic module was fabricated using LTCC technology. The possibility for the fabrication of an enzymatic microreactor in a multilayer ceramic substrate, made of CeramTec glass ceramic (GC) material systems with an integrated thick-film heater, is studied. Different configurations of the LTCC/heater materials (gold, silvers and palladium-silver) are taken into account. The performance of the LTCC-based microfluidic module with the integrated heater and immobilized enzyme was examined experimentally.

A compatible material for the heater embedded in the CeramTec GC-based structures was found. The preliminary measurements made for the test solution containing various concentrations of urea have shown stability (for seven days of operation) and a relatively high signal-to-noise ratio (above 3 pH units) for the microreactor’s output signal.

The presented research is a preliminary work which is focused on the fabrication of the LTCC-based microfluidic module, with an integrated heater and immobilized enzyme for urea determination. The device was positively tested using a model reaction of the hydrolysis of urea. However, urea concentration in real (biological) fluid should also be measured.

The development of the LTCC-based microfluidic module for urea determination provides opportunity for the construction of a lab-on-chip, or μTAS-type system, for fast medical diagnoses and the continuous monitoring of various biochemical parameters, e.g. for estimating the effectiveness of hemodialysis.

This paper shows the design, fabrication and performance of the novel microfluidic module for urea determination, made with LTCC technology.

Aluminium-doped zinc oxide thin films exhibit interesting optoelectronic properties, which make them suitable for fabrication of photovoltaic cell, flat panel display electrode, etc. It has been shown that aluminium dopant concentration and annealing treatment in reduced atmosphere are the major factors affecting the electrical and optical properties of aluminium doped zinc oxide (AZO) film. Here, the authors report the structural, optical and electrical properties of aluminium-doped zinc oxide thin films fabricated by dip coating technique and annealed in air atmosphere, thereby avoiding hazardous environments such as hydrogen. The aim of this paper was to systematically investigate the effect of annealing temperature on the electrical properties of dip-coated film.

Aluminium-doped ZnO thin films were prepared on corning substrates by dip coating method. Aluminium concentration in the film varied from 0.8 to 1.4 mol per cent. Films have been characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, UV-visible spectroscopy and Hall measurements. The deposited films were heat treated at 450-600°C, in steps of 50°C for 1 h in air to study the improvement in electrical properties. Films were also prepared by annealing at 600°C in air for durations of 1, 2, 4 and 6 h. Envelope method was used to calculate the variation of the refractive index and extinction coefficient with wavelength.

The electrical resistivity is found to decrease considerably when the annealing time is increased from 1 to 4 h. The films exhibited high transmittance (>90 per cent) in the visible range, and the optical band gaps were found to change as per the Moss–Burstien effect, and this was consistent with the observed changes in the carrier concentration.

The study shows the effect of annealing in air, avoiding hazardous reduced environment, such as hydrogen, to study the improvement in electrical and optical properties of aluminum-doped zinc oxide films. Envelope method was used to calculate the variation of optical constants with wavelength.

This paper aims to develop a low-cost hot-point which can facilitate the conductivity type of N-type and P-type zinc oxide (ZnO) films. In this study, a diode was made out of the N-type and P-type ZnO films, and current-voltage (I-V) characteristic measurements were conducted.

A low-cost hot-point probe consists of a soldering iron station, digital multimeter and a pair of probes. The setup is adopted to identify N-type and P-type ZnO films. In particular, P-type films have been deployed for the first time.

Hot-point probe setup has been successfully developed. Measurements of N-type films give a positive voltage reading, whereas P-type films give a negative voltage reading. The measured voltage dominates at 1 per cent for N-type Ga and at 15 per cent for P-type Na. I-V characteristics of the fabricated diode showed a similar trend to the conventional diode.

N-type has been often attempted. However, P-type has rarely been attempted because of the self-compensation effect in ZnO. There is a need to verify the conductivity type of ZnO films, especially P-type, as P-type films are not stable. The hot-point probe setup serves as a quick means to verify P-type ZnO films.

To the best of the authors’ understanding, this verification tool was developed and deployed to verify the N-type and P-type ZnO films. The P-type films are coated on top of the N-type films for diode I-V measurements.

This paper aims to present a research on utilization of an irreversible bonding between non-transparent low temperature co-fired ceramics (LTCC) and transparent poly(dimethylsiloxane) (PDMS). The research presented in this paper is focused on the technology and performance of the miniature microfluidic module for fluorescence measurement.

The chemical combination of both materials is achieved through surface modification using argon-oxygen dielectric barrier discharge (DBD) plasma. According to the performed spectroscopic analyses (X-ray photoelectron spectroscopy, XPS; attenuated total reflection-Fourier infrared spectroscopy, ATR-FTIR) and contact angle measurements, the LTCC and PDMS surfaces are oxidized during the process. The presented microfluidic module was fabricated using LTCC technology. The possibility for the fabrication of LTCC-PDMS microfluidic fluorescent sensor is studied. The performance of the sensor was examined experimentally.

As a result of DBD plasma oxidation, the LTCC and PDMS surfaces change in character from hydrophobic to hydrophilic and were permanently bonded. The presented LTCC-PDMS bonding technique was used to fabricate a microfluidic fluorescent sensor. The preliminary measurements of the sensor have proven that it is possible to observe the fluorescence of a liquid sample from a very small volume.

The presented research is a preliminary work which is focused on the fabrication of the LTCC-PDMS fluorescent sensor. The microfluidic device was positively tested only for ethanolic fluorescein solutions. Therefore, fluorescence measurements should be performed for biological specimen (e.g. DNA).

The LTCC-PDMS bonding technology combines the advantages of both materials. One the one hand, transparent PDMS with precise, transparent three-dimensional structures can be fabricated using hot embossing, soft lithography or laser ablation. On the other hand, rigid LTCC substrate consisting of microfluidic structures, electric interconnections, heaters and optoelectronic components can be fabricated. The development of the LTCC-PDMS microfluidic modules provides opportunity for the construction of a lab-on-chip, or micro-total analysis systems-type system, for analytical chemistry and fast medical diagnoses.

This paper shows utilization of the PDMS-LTCC bonding technology for microfluidics. Moreover, the design, fabrication and performance of the PDMS-LTCC fluorescent sensor are presented.

This paper aims to investigate different properties of synthesized perovskite Sm_0.9Sr_0.1CoO_3-δ and its potential for application in potentiometric oxygen sensors.

The powder was obtained through solid-state reaction method and characterized by thermogravimetric/differential thermal analyzer and X-ray diffraction. It was used for both making a paste and pressing into rods for sintering. The prepared paste was deposited on alumina and yttria-stabilized zirconia substrates, by screen printing. Thick film conductivity, bulk conductivity and Seebeck coefficient of sintered rods were measured as a function of temperature. An oxygen concentration cell was fabricated with the screen-printed perovskite material as electrodes.

Electrical conductivity of the bulk sample and thick film increases with the increase in temperature, showing semiconductor-like behavior, which is also indicated by relatively high values of the measured Seebeck coefficient. Estimated values of the activation energy for conduction are found to be of the same magnitude as those reported in the literature for similar composition. An investigation of Nernstian behavior of the fabricated cell confirmed that Sm_0.9Sr_0.1CoO_3-δ is a promising material for application in oxygen potentiometric sensors.

Gas sensor research is focused on the development of new sensitive materials. Although there is scarce information on SmCoO_3-δ in the literature, it is mostly investigated for fuel cell applications. Results of this study imply that Sr-doped SmCoO_3-δ is a good candidate material for oxygen potentiometric sensor.

This paper aims to present a comparison between three types of manufacturing techniques, namely, screen-printed, inkjet and gravure, using different types of inks, for the implementation of concentric ring electrodes which permit estimation of Laplacian potential on the body surface.

Flexible concentric ring electrodes not only present lower skin–electrode contact impedance and lower baseline wander than rigid electrodes but are also less sensitive to interference and motion artefacts. The above three techniques allow printing of conductive inks on flexible substrates, and with this work, the authors aim to study which is the best technique and ink to obtain the best electrode response.

From the results obtained regarding ink thickness, resistivity, electrode resistance and other performance parameters derived from electrocardiographic signal recording tests, it can be said that concentric electrodes using the screen-printing and inkjet techniques are suitable for non-invasive bioelectric signal acquisition.

The development of new types of inks and substrates for the electronics industry and the adaptation of new manufacturing techniques allow for an improvement in the development of electrodes and sensors.

This paper aims to present a prototype of the diagnostic system for the examination of the distribution of the force applied by foot to substrate during usual human moving. Presented system is competitive to other currently available devices, thanks to sensors reliability, user-friendly operation manner and design based on cheap parts. The results of examinations are transmitted by radiomodem. Its recording and visualization are possible on either personal or mobile computers.

During selection of the sensors substrate, many polymeric electrets were examined. Polyvinylidene fluoride films were selected, because they have good charge uniformity across the surface, wide range of acceptable temperatures, linear relation between mechanical stress and output signal and high resistance for squeezing. The system measures the charge generated in film.

The pressures are recorded in relation to maximum value; therefore, measuring system does not require calibration. The simultaneous recording of data from all eight sensors allows tracking the signal without distortion.

An array of sensors is installed in the shoe insole. The measuring device is fixed to the outer surface of the shoe. Its weight is 75 g. The range of transmission is suitable for examination in the natural environment, outside traditional consulting room. Software is dedicated for analysis of the pressure distribution in every moment of the foot movement. The system is suitable for examination of flat feet, diabetic foot and recovery progress after injures.

The purpose of this research is to study the effect of thickness and surface properties of ZnO solid thin film for heat dissipation application in LED. Heat dissipation in electronic packaging can be improved by applying a thermally conductive interface material (TIM) and hence the junction temperature will be maintained. ZnO is one of the oxide materials and used as a filler to increase the thermal conductivity of thermal paste. The thickness of these paste-type material cannot be controlled which restricts the heat flow from the LED junction to ambient. The controlled thickness is only possible by using a solid thin-film interface material.

Radio Frequency (RF)-sputtered ZnO thin film on Cu substrates were used as a heat sink for high-power LED and the thermal performance of various ZnO thin film thickness on changing total thermal resistance (R _th-tot) and rise in junction temperature were tested. Thermal transient analysis was used to study the performance of the given LED. The influence of surface roughness profile was also tested on the LED performance.

The junction temperature was high (6.35°C) for 200 nm thickness of ZnO thin film boundary condition when compared with bare Cu substrates. Consecutively, low R _th-tot values were noticed with the same boundary condition. The 600 nm thickness of ZnO thin film exhibited high R _th-tot and interface resistance than the other thicknesses. Bond Line Thickness of the interface material was influenced on the interface thermal resistance which was decreased with increased BLT. Surface roughness parameter showed an immense effect on thermal transport, and hence, low R _th (47.6 K/W) value was noticed with low film roughness (7 nm) as compared with bare Cu substrate (50.8 K/W) where the surface roughness was 20.5 nm.

Instead of using thermal paste, solid thin film ZnO is used as TIM and coated Cu substrates were used as a heat sink. The thickness can be controlled, and it is a new approach for reducing the BLT between the metal core printed circuit board and heat sink.