Flexible, textronic temperature sensors, based on carbon nanostructures

The paper presents a comparative analysis of two types of flexible temperature sensors, made of carbon-based nanostructures composites. These sensors were fabricated by a low-cost screen-printing method, which qualifies them to large scale, portable consumer electronic products. Results of examined measurements show the possibility of application for thick film devices, especially dedicated to wearable electronics, also known as a textronics. Apart from general characterisation, the influence of technological processes on specific sensor parameters were examined, particulary the value of the temperature coefficient of resistance (TCR) and its stability during the device bending

Review of Luminescence-Based Light Spectrum Modifications Methods and Materials for Photovoltaics Applications

The dynamic development of photovoltaic and photo-sensitive electronic devices is constantly stimulated by material and technological advances. One of the key concepts that is highly recommended for the enhancement of these device parameters is the modification of the insulation spectrum. Practical implementation of this idea, although difficult, may be highly beneficial for photoconversion efficiency, photosensitivity range extension, and their cost reduction. The article presents a wide range of practical experiments leading to the manufacturing of functional photoconverting layers, dedicated to low-cost and wide-scale deposition methods. Various active agents, based on different luminescence effects as well as the possible organic carrier matrixes, substrate preparation and treatment procedures, are presented. New innovative materials, based on their quantum effects, are examined. The obtained results are discussed in terms of the application in new generation photovoltaics and other optoelectronic elements

Renewable energy electric sources as a support for multilevel cellular communication networks in various environment conditions : case study

Cellular mobile communication networks are experiencing an important evolution with the emerging deployment of 5G networks and the successive decline in the use of previous generations in the years to come. In parallel, policies promoting ecological transition are gaining social impact and economic interest and this seems to be the trend in the near future. In the telecommunications market, the shift between two dominant generations could be an important opportunity to introduce renewable energy sources to green the sector, reducing the carbon footprint of the world-wide extended activity. This work analyses the current situation and provides an insight into the possibilities to incorporate renewable energy supplies, specifically photovoltaics (as it seems to be the most promising among clean electric sources), perhaps combined with small wind turbines in off-grid systems. Paper also compares the characteristics of standard facilities in Spain and Poland, two different European countries in terms of weather and insolation hours

Tests and theoretical analysis of a PVT hybrid collector operating under various insolation conditions

The main goal of the study was to investigate the relationship between the orientation of the PVT (PhotoVoltaic Thermal) collector and the thermal and electric power generated. Extensive research was performed to find optimal tilt angles for hybrid solar thermal collectors, which combine photovoltaic as well as thermal collection in a single unit, known as PVT (PhotoVoltaic Thermal) modules for an office building with working hours between 7.00 and 16.00. The comprehensive study included field measurements of the modules in central Poland and tests under AM (air mass) 1.5 conditions in a certified laboratory KEZO (Centre for Energy Conversion and Renewable Resources) Polish Academy of Sciences in Jablonna. Furthermore, a PVT system was investigated using the simulation method based on the dedicated Polysun software. The PV characteristics and efficiency of the PV module and the relation between power or efficiency of the PVT module and incidence angle of solar-irradiance were studied. Optimal work conditions for commercial PVT modules were ascertained. In addition, it was found that the maximum efficiencies of PV module (ηPV), solar thermal-collector (ηc) and PVT hybrid collector (ηPVT) registered under field conditions were higher than the ones measured under laboratory conditions.</p

Spray Coating Luminescence Layers on Glass for Si Solar Cells Efficiency Enhancement

The article presents experimental research focused on the improvement of solar cells efficiency using the photoluminescence down-shifting effect. In the paper, the authors present the results of solar cells performance enhanced with the proposed solution. As light energy converted active materials, rare earth elements of europium and dysprosium were implemented. In the experiments, luminescent layers were deposited on top of photovoltaic protective glass in order to absorb the highest possible amount of ultraviolet light from the incident solar spectrum. Spray coating deposition technology with various types of ink compositions was used for process optimization. It was observed that there are optimal concentrations and solvent types for the best conversion effect and consequently, the improvement of solar cell external quantum efficiency (EQE) together with the PV cell absolute efficiency enhancement

UV–visible silicon detectors with zinc oxide nanoparticles acting as wavelength shifters

International audienceBroad spectral response of photon detectors without cryogenic cooling is of great interest inmany fields of application like spectroscopy and high-energy particle physics. In order to achieve it,different approaches can be found in literature. One approach is the multijunction detectorincorporating different kind of absorbers. The drawback here is the fabrication cost as well ascomplicated fabrication technique [1]. Another approach is the application of wavelength shifterswhich absorb the UV light and re-emit it in the lower energy range which preferably matches thepeak sensitivity of the detector. The application of chemical wavelength shifters like e.g. TetraphenylButadiene (TPB) has been reported, but they posses some drawbacks like instability in contact withsome substances and photo-degradation behavior [2]. There is also a concept of the application ofluminescent nanoparticles on top of the detector, which act as wavelength shifters [3]. This approachhas several advantages such as little interference in the detector structure (even the UV-blockingwindow of the detector does not pose a problem), straightforward deposition technique and largepossibility of adjustment of the spectral regions depending on the kind of the nanoparticles. Thanksto the quantum confinement the absorption and emission properties of the material can be tuned.Other feature which has an impact on the emission and excitation properties are the defects, whichcan act as luminescent centers. The wavelength shifters considered for this application are two kindsof commercially available zinc oxide (ZnO) nanoparticles. The differences between them lay in thesize and the structural quality, which influence their optical properties like emission and excitationspectra as well as photoluminescence quantum yield. For the application they are distributed in thepoly (methyl methacrylate) – PMMA - matrix and spin-coated on the detector window. The workconsists of the analysis of the parameters of the zinc oxide nanopowders as well as the nanopowdersdispersed in the PMMA matrix. The problem has been investigated both theoretically andexperimentally. The experimental part involved examination of the samples deposited on thelaboratory glass and finally on the photodetector. Apart from the kind of zinc oxide nanoparticles, thetechnological parameters which were optimised was the concentration of ZnO in PMMA as well asthickness of the layer. Two types of photodetectors have been considered for modification: siliconphotodiodes with broad spectral response from 190 nm to 1000 nm and Multi Pixel Photon Counters(MPPC) sensitive in the range 270 – 900 nm. These latter ones are used for sophisticated applicationsas well as single-photon detection. The comparison of parameters of the detectors before and aftermodification is shown.References[1] Gessert, T.A., Colegrove, E., Stafford, B., Kodama, R., Gao, W., Moutinho, H.R., Kuciauskas, D., Reedy,R.C., Barnes, T.M., Sivananthan, S. MRS Advances 1, (50), pp. 3391-3402 (2016).[2] Álvarez, V. et al., Journal of Instrumentation 7, P02010 (2012).[3] Sahi, S., Magill, S., & Ma, L., Xie, J., Chen, W., Jones, B., Nygren, D., Scientific Reports 8, 10515 (2018)

Review on metallic oxide nanoparticles and their application in optoelectronic devices

Among the large family of metallic oxides, there is a considerable group possessing excellent semiconducting properties. What follows, they are promising materials for applications in the field of optoelectronics and photonics. Thanks to the development of nanotechnology in the last few decades, it is now possible to manufacture a great variety of different nanostructures. By controlling their size, shape, composition and crystallinity, one can influence such properties as band gap, absorption properties, surface to volume ratio, conductivity, and, as a consequence, tune the material for the chosen application. The following article reviews the research conducted in the field of application of the metallic oxide nanoparticles, especially ZnO, TiO2 and ITO (Indium-Tin Oxide), in such branches of optoelectronics as solid-state lightning, photodetectors, solar-cells and transparent conducting layers

Tests and theoretical analysis of a PVT hybrid collector operating under various insolation conditions

The main goal of the study was to investigate the relationship between the orientation of the PVT (PhotoVoltaic Thermal) collector and the thermal and electric power generated. Extensive research was performed to find optimal tilt angles for hybrid solar thermal collectors, which combine photovoltaic as well as thermal collection in a single unit, known as PVT (PhotoVoltaic Thermal) modules for an office building with working hours between 7.00 and 16.00. The comprehensive study included field measurements of the modules in central Poland and tests under AM (air mass) 1.5 conditions in a certified laboratory KEZO (Centre for Energy Conversion and Renewable Resources) Polish Academy of Sciences in Jablonna. Furthermore, a PVT system was investigated using the simulation method based on the dedicated Polysun software. The PV characteristics and efficiency of the PV module and the relation between power or efficiency of the PVT module and incidence angle of solar-irradiance were studied. Optimal work conditions for commercial PVT modules were ascertained. In addition, it was found that the maximum efficiencies of PV module (ηPV), solar thermal-collector (ηc) and PVT hybrid collector (ηPVT) registered under field conditions were higher than the ones measured under laboratory conditions