Search

Covid is giving us many lessons among which one must be to realize that this is the time to act for sustainable future. The smart world around us has made it inevitable to have an alarming situation regarding the uncontrolled growth of waste products such as plastic and electronic wastes. Both are immense threats to the health of human, wildlife and environment, that eventually affect the societal and economic structures as evident from recent Covid-crisis. The proper management of these wastes and innovating ideas for new sustainable technologies are the need of the hour. Circular economy act with green technology (green economy) is the way to tackle this challenge. Current perspective presents the overview of the scenario regarding these burgeoning issues and demonstrates some measures that are taken or being considered to depend on to come out of them. [Display omitted] • Zero Waste Challenge is the idea to guide people in changing their lifestyles and practices to minimize the negative environmental impacts. • Most of the three challenging sectors in waste stream is plastics, electronics and medical. • The main three criteria to adopt green economy is reduce, reuse and recycling of manufacturing products. [ABSTRACT FROM AUTHOR]

The energy band alignments at interfaces often determine the electrical functionality of a device. Along with the size reduction into the nanoscale, functional coatings become thinner than a nanometer. With the traditional analysis of the energy band alignment by in situ photoelectron spectroscopy, a critical film thickness is needed to determine the valence band offset. By making use of the Auger parameter, it becomes possible to determine the energy band alignment to coatings, which are only a few Ångström thin. This is demonstrated with experimental data of Cu2O on different kinds of substrate materials. [ABSTRACT FROM AUTHOR]

In the last decade the use of field-effect-based devices has become a basic structural element in a new generation of biosensors that allow label-free DNA analysis. In particular, ion sensitive field effect transistors (FET) are the basis for the development of radical new approaches for the specific detection and characterization of DNA due to FETs' greater signal-to-noise ratio, fast measurement capabilities, and possibility to be included in portable instrumentation. Reliable molecular characterization of DNA and/or RNA is vital for disease diagnostics and to follow up alterations in gene expression profiles. FET biosensors may become a relevant tool for molecular diagnostics and at point-of-care. The development of these devices and strategies should be carefully designed, as biomolecular recognition and detection events must occur within the Debye length. This limitation is sometimes considered to be fundamental for FET devices and considerable efforts have been made to develop better architectures. Herein we review the use of field effect sensors for nucleic acid detection strategies--from production and functionalization to integration in molecular diagnostics platforms, with special focus on those that have made their way into the diagnostics lab. [ABSTRACT FROM AUTHOR]

Abstract: ZnO is a natural n-type widespread semiconductor with wide direct bandgap of 3.37eV, large exciton bending energy (60meV) and high optical gain (300cm−1). One dimensional ZnO nanomaterials such as nanowires or nanorods have focused much attention due to their multifunctionality in optoelectronic devices, gas sensing, piezoelectricity and thin film transistors for transparent and flexible electronics. Solution-phase chemical synthesis of nanomaterials has several important advantages, as low temperatures, high versatility, low cost, simple equipments and handling. The paper presents the chemical bath deposition synthesis and characterization of ZnO 1D nanostructures grown on glass substrates seeded with gold layer, pre-prepared ZnO nanoparticles or sol–gel derived ZnO layer. The obtained ZnO nanowires/nanorods were structurally and morphologically characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and the growth mechanism is discussed. The seed layer significantly affects the surface distribution and orientation of the grown 1D nanostructures. The diameter of the nanowires is mainly controlled by the concentration and temperature of the growth solution. The effect of growth conditions on the surface chemical composition and surface states/defects of semiconducting 1D nanostructures was investigated using X-ray photoelectron spectroscopy. The optical and electrical properties are presented. [Copyright &y& Elsevier]

This work describes the fabrication and characterization of an improved version of large area (5 mm×80 mm with an active length of 70 mm) flexible position sensitive detectors deposited onto polymeric substrates (polyimide–Kapton® VN). The new configuration presented by the sensor is based on a heterostructure of a-Si:H/ZnO:Al. The sensors were characterized by spectral response, photocurrent dependence as a function of light intensity and position detection measurements. The set of data obtained on one-dimensional position sensitive detectors based on the heterostructure show excellent performances with a maximum spectral response of 0.12 A/W at 500 nm and a non-linearity of ±10% over 70 mm length. The produced sensors present a non-linearity higher than those ones produced on glass substrates, due to the different thermal coefficients exhibited by the polymer and the amorphous silicon film. In order to prove this behaviour, it was measured the defect density obtained by the constant photocurrent method on amorphous silicon deposited on polymeric substrates bended with different radius of curvature. [Copyright &y& Elsevier]

In this work, we show the possibility to use undoped porous silicon (PS) thin films produced by hot wire chemical vapour deposition technique (HW-CVD) as ethanol detector. Silicon thins films produced by HW-CVD technique, under certain deposition conditions, have a porous structure . Therefore, in the presence of an alcohol, the OH group is adsorbed by the uncompensated bonds behaving as donor-like carriers leading to an increase in the current flowing through the material. This current enhancement is bias dependent in glass/ITO/i-a-Si:H/Al sensor and increases as the ethanol vapour pressure increases from 10-1 mbar to atmospheric pressure. The response time of the current of the sensor and its recovery time are in the range of 10–50 s at room temperature. Ethanol quantities above 50 ppm can be detected. [Copyright &y& Elsevier]

In this paper, we present the preliminary results concerning the deposition of highly transparent and conductive gallium-doped zinc oxide (GZO) deposited on transparent flexible substrate based on cellulose derivatives. Prior to the deposition of the GZO film, the surface of the polymer have been coated with a thin silicon dioxide (SiO2) layer deposited by thermal evaporation assisted by an electron gun. By doing this surface treatment, we succeeded in depositing highly conductive and transparent GZO with an electrical resistivity of 2.0×10−3 Ω cm and an average optical transmittance in the visible part of the spectrum (400–700 nm) of 70% by r.f. magnetron sputtering at room temperature. Besides the optoelectronic properties, the films are mechanically stable with a polycrystalline structure with a strong preferred (002) orientation, parallel to the substrate. [Copyright &y& Elsevier]

In this paper, we present results concerning the thickness dependence (from 70 to 890 nm) of electrical, structural, morphological and optical properties presented by gallium-doped zinc oxide (GZO) deposited on polyethylene naphthalate (PEN) substrates by r.f. magnetron sputtering at room temperature. For thicknesses higher than 300 nm an independent correlation between the electrical, morphological, structural and optical properties are observed. The lowest resistivity obtained was 5×10−4 Ω cm with a sheet resistance of 15 Ω/□ and an average optical transmittance in the visible part of the spectra of 80%. It is also shown that by passivating the surface of the polymer by depositing a thin silicon dioxide layer the electrical and structural properties of the films are improved nearly by a factor of two. [Copyright &y& Elsevier]

Gallium-doped zinc oxide films were prepared by r.f. magnetron sputtering at room temperature as a function of the substrate–target distance. The best results were obtained for a distance of 10 cm, where a resistivity as low as 2.7×10−4 Ω cm, a Hall mobility of 18 cm2/Vs and a carrier concentration of 1.3×1021 cm−3 were achieved. The films are polycrystalline presenting a strong crystallographic c-axis orientation (002) perpendicular to the substrate. The films present an overall transmittance in the visible part of the spectra of approximately 85%, on average. [Copyright &y& Elsevier]

Extensive research into green technologies is driven by the worldwide push for eco‐friendly materials and energy solutions. The focus is on synergies that prioritize sustainability and environmental benefits. This study explores the potential of abundant, non‐toxic, and sustainable resources such as paper, lignin‐enriched paper, and cork for producing laser‐induced graphene (LIG) supercapacitor electrodes with improved capacitance. A single‐step methodology using a CO2 laser system is developed for fabricating these electrodes under ambient conditions, providing an environmentally friendly alternative to conventional carbon sources. The resulting green micro‐supercapacitors (MSCs) achieve impressive areal capacitance (≈7–10 mF cm−2) and power and energy densities (≈4 μW cm‐2 and ≈0.77 µWh cm−2 at 0.01 mA cm−2). Stability tests conducted over 5000 charge–discharge cycles demonstrate a capacitance retention of ≈80–85%, highlighting the device durability. These LIG‐based devices offer versatility, allowing voltage output adjustment through stacked and sandwich MSCs configurations (parallel or series), suitable for various large‐scale applications. This study demonstrates that it is possible to create high‐quality energy storage devices based on biodegradable materials. This development can lead to progress in renewable energy and off‐grid technology, as well as a reduction in electronic waste. [ABSTRACT FROM AUTHOR]

Presents a model to interpret the steady-state and the dynamic detection limits of one dimensional thin film position sensitive detectors based on p-i-n a-Si:H devices. Description of the theoretical model; Potential and lateral current static distributions; Determination of the device transient response; Experimental setup.

P-type thin-film transistors (TFTs) using room temperature sputtered SnOx (x<2) as a transparent oxide semiconductor have been produced. The SnOx films show p-type conduction presenting a polycrystalline structure composed with a mixture of tetragonal β-Sn and α-SnOx phases, after annealing at 200 °C. These films exhibit a hole carrier concentration in the range of ≈1016–1018 cm-3; electrical resistivity between 101–102 Ω cm; Hall mobility around 4.8 cm2/V s; optical band gap of 2.8 eV; and average transmittance ≈85% (400 to 2000 nm). The bottom gate p-type SnOx TFTs present a field-effect mobility above 1 cm2/V s and an ON/OFF modulation ratio of 103. [ABSTRACT FROM AUTHOR]

Copper oxide (Cu2O) thin films were used to produce bottom gate p-type transparent thin-film transistors (TFTs). Cu2O was deposited by reactive rf magnetron sputtering at room temperature and the films exhibit a polycrystalline structure with a strongest orientation along (111) plane. The TFTs exhibit improved electrical performance such as a field-effect mobility of 3.9 cm2/V s and an on/off ratio of 2×102. [ABSTRACT FROM AUTHOR]

High mobility bottom gate thin film transistors (TFTs) with an amorphous gallium tin zinc oxide (a-GSZO) channel layer have been produced by rf magnetron cosputtering using a gallium zinc oxide (GZO) and tin (Sn) targets. The effect of postannealing temperatures (200, 250, and 300 °C) was evaluated and compared with two series of TFTs produced at room temperature (S1) and 150 °C (S2) during the channel deposition. From the results, it was observed that the effect of postannealing is crucial for both series of TFTs either for stability as well as for improving the electrical characteristics. The a-GSZO TFTs (W/L=50/50 μm) operate in the enhancement mode (n-type), present a high saturation mobility of 24.6 cm2/V s, a subthreshold gate swing voltage of 0.38 V/decade, a turn-on voltage of -0.5 V, a threshold voltage of 4.6 V, and an Ion/Ioff ratio of 8×107, satisfying all the requirements to be used as active-matrix backplane. [ABSTRACT FROM AUTHOR]

Electronic skin (e-skin), which is an electronic surrogate of human skin, aims to recreate the multifunctionality of skin by using sensing units to detect multiple stimuli, while keeping key features of skin such as low thickness, stretchability, flexibility, and conformability. One of the most important stimuli to be detected is pressure due to its relevance in a plethora of applications, from health monitoring to functional prosthesis, robotics, and human-machine-interfaces (HMI). The performance of these e-skin pressure sensors is tailored, typically through micro-structuring techniques (such as photolithography, unconventional molds, incorporation of naturally micro-structured materials, laser engraving, amongst others) to achieve high sensitivities (commonly above 1 kPa−1), which is mostly relevant for health monitoring applications, or to extend the linearity of the behavior over a larger pressure range (from few Pa to 100 kPa), an important feature for functional prosthesis. Hence, this review intends to give a generalized view over the most relevant highlights in the development and micro-structuring of e-skin pressure sensors, while contributing to update the field with the most recent research. A special emphasis is devoted to the most employed pressure transduction mechanisms, namely capacitance, piezoelectricity, piezoresistivity, and triboelectricity, as well as to materials and novel techniques more recently explored to innovate the field and bring it a step closer to general adoption by society. [ABSTRACT FROM AUTHOR]

We report high-perfomance ZnO thin-film transistor (ZnO-TFT) fabricated by rf magnetron sputtering at room temperature with a bottom gate configuration. The ZnO-TFT operates in the enhancement mode with a threshold voltage of 19 V, a saturation mobility of 27 cm2/V s, a gate voltage swing of 1.39 V/decade and an on/off ratio of 3 × 105. The ZnO-TFT presents an average optical transmission (including the glass substrate) of 80% in the visible part of the spectrum. The combination o f transparency, high mobility, and room-temperature processing makes the ZnO-TFT a very promising low-cost optoelectronic device for the next generation of invisible and flexible electronics. [ABSTRACT FROM AUTHOR]

Exploitation of low‐dimensional metal‐oxide semiconductor nanowires (MOS NWs) with peculiar and radial coaxial architectures is of great significance for constructing nanoscale, high‐performance, multi‐module integrable functional electronic products. Here, highly ordered In2O3@ZnO coaxial NW arrays (CNWA) using a simple and economical electrospinning technique are synthesized and assembled into field‐effect transistors (FETs). Featuring strong carrier effusion efficiency at the In2O3@ZnO circular heterogeneous interface, the field effect mobility (εFE) gets an intrinsic improvement and can reach as high as 202.3 cm2 V‒1 s‒1 for high‐k‐based CNWA FETs, which exceeds the performance of oxide‐based FETs devices reported by far. Furthermore, the unique structural advantages endowing In2O3@ZnO CNWA FETs with excellent optoelectronic coupling capabilities are identified, for which further optoelectronic detection and artificial photonic synaptic devices are constructed and functional simulations are implemented. This work offers new insights in designing optoelectronics and artificial synapses to process and recognize information for neuromorphic computing and artificial intelligence applications. [ABSTRACT FROM AUTHOR]

The application of hydrogenated amorphous silicon (a-Si:H) to optoelectronic devices are now well established as a viable low cost technology and is presently receiving much interest. Taking advantage of the properties of a-Si:H based devices, single and dual axis large area (up to 80×80 mm²) thin film position sensitive detectors (TFPSD) based on a-Si:H p-i-n diodes have been developed, produced by plasma enhanced chemical vapor deposition. In this study, the main optoelectronic properties presented by the TFPSD as well as their behavior under operation conditions, concerning its linearity and signal to noise ratio, are reported. [ABSTRACT FROM AUTHOR]

In this study, a novel approach was used for the preparation of α-Fe2O3 films via electrodeposition followed by hydrothermal treatment for different time periods. The impacts of the time taken for hydrothermal treatment on the structure and morphology of the electrodeposited films were investigated. According to the X-ray diffraction and Raman spectroscopy results, the alpha structure type showed a unique pure phase. The α-Fe2O3 possessing two phases was revealed for the nanoparticles coated with nanorods by scanning electron microscopy. The energy dispersive X-ray microscopy displayed a remarkable decrease in the intensity of the Tin element due to the formation of nanorods on the nanoparticles. The results showed that the ascending increase in the time for hydrothermal treatment led to significant changes in film morphology and chemical composition with a direct consequence on the photocatalytic performance. The α-Fe2O3 films exhibited high efficiency towards the degradation of methylene blue, which was attributed to its structure. [ABSTRACT FROM AUTHOR]

Metal oxide field‐effect transistors (MOFETs) represent a promising technology for applications in existing but alsoemerging large‐area electronics. Simultaneously, the rise of 1D nanomaterials with unique properties, represented by nanofibers (NFs), has also energized research. Thus, developing 1D nanofiber networks (NFNs) to act as the potential building blocks for use in fundamental elements of transistors is considered to be a promising approach torealize high‐performance 1D electronics. However, high processing temperatures and disordered nanofiber distribution represent two remaining technical challenges. Here, electrospun highly aligned IGZO (a‐IGZO) nanofiber arrays with low‐thermal‐budget of 350 °C and impressive device characteristics are achieved, including a μFE of 5.63 cm2 V–1 s–1 and superior on/off current ratio of ≈107. When ALD‐derived high‐k HfAlOx thin films are employed as gate dielectrics, the source/drain voltage (VDS) can be substantially reduced by ten times to a range of only 03 V, along with a three times improvement in mobility to a respectable value of 15.9 cm2 V–1 s–1. Successful integrations of logic operation, sensor, and flexible devices implies the potential prospect of a‐IGZO NFN FETs in multifunctional electronics. The strategy for combining cryogenic processes and parallel arrays provides a feasible and reliable route in building future low‐power, high‐performance flexible electronics. [ABSTRACT FROM AUTHOR]

The effect of substrate temperature on the direct current magnetron‐sputtered zirconium oxide (ZrO2) dielectric films was investigated. Stoichiometric of the ZrO2 thin films was obtained at an oxygen partial pressure of 4.0 × 10−2 Pa. X‐ray diffraction studies revealed that the crystallite size in the layer was increased from 4.8 to 16.1 nm with increase of substrate temperature from 303 to 673 K. Metal‐oxide‐semiconductor devices were fabricated on ZrO2/Si stacks with Al gate electrode. The dielectric properties of ZrO2 layer and interface quality at ZrO2/Si were significantly influenced by the substrate temperature. The dielectric constant increased from 15 to 25, and the leakage current density decreased from 0.12 × 10−7 to 0.64 × 10−9 A cm−2 with the increase of substrate temperature from 303 to 673 K. [ABSTRACT FROM AUTHOR]

Solution combustion synthesis (SCS) has been widely used to produce simple and complex oxides with a desired morphology (size and shape). SCS is valuable due to low cost, simplicity and energy efficient synthesis. To guarantee the best molecular‐level mixing of reactants in an aqueous or solvent‐based solution some parameters need to be controlled, such as fuel type, metal cations precursors, stoichiometry ratio (φ), pH effect, atmosphere and initiation type. These determine the final properties of the oxide materials, providing the potential to reach different morphologies, which are essential for their final applications. This Review article focuses on the crucial parameters in SCS and how these affect the overall materials properties from nanostructures to thin films. To finalize, special attention is given to the application of SCS to form metal oxide thin films at low temperature and their application in thin film transistors (TFTs). [ABSTRACT FROM AUTHOR]

[Display omitted] • Extensive characterization of gold nanoparticles for photothermal therapy. • The effect of the gold salt on physicochemical and optical properties. • Gold atoms face-centered cubic structure confirmed by microscopy. • Photothermal conversion efficiency calculated by theoretical/experimental data. • In vivo local retention of nanoparticles confirmed by computerized tomography. Among the unique characteristics associated to gold nanoparticles (AuNPs) in biomedicine, their ability to convert light energy into heat opens ventures for improved cancer therapeutic options, such as photothermal therapy (PTT). PTT relies on the local hyperthermia of tumor cells upon irradiation with light beams, and the association of AuNPs with radiation within the near infrared (NIR) range constitutes an advantageous strategy to potentially improve PTT efficacy. Herein, it was explored the effect of the gold salt on the AuNPs' physicochemical and optical properties. Mostly spherical-like negatively charged AuNPs with variable sizes and absorbance spectra were obtained. In addition, photothermal features were assessed using in vitro phantom models. The best formulation showed the ability to increase their temperature in aqueous solution up to 19 °C when irradiated with a NIR laser for 20 min. Moreover, scanning transmission electron microscopy confirmed the rearrangement of the gold atoms in a face-centered cubic structure, which further allowed to calculate the photothermal conversion efficiency upon combination of theoretical and experimental data. AuNPs also showed local retention after being locally administered in in vivo models. These last results obtained by computerized tomography allow to consider these AuNPs as promising elements for a PTT system. Moreover, AuNPs showed high potential for PTT by resulting in in vitro cancer cells' viability reductions superior to 70 % once combine with 5 min of NIR irradiation. [ABSTRACT FROM AUTHOR]

Early and accurate detection of infection by pathogenic microorganisms, such as Plasmodium, the causative agent of malaria, is critical for clinical diagnosis and ultimately determines the patient's outcome. We have combined a polystyrene-based microfluidic device with an immunoassay which utilises Surface-Enhanced Raman Spectroscopy (SERS) to detect malaria. The method can be easily translated to a point-of-care testing format and shows excellent sensitivity and specificity, when compared to the gold standard for laboratorial detection of Plasmodium infections. The device can be fabricated in less than 30 min by direct patterning on shrinkable polystyrene sheets of adaptable three-dimensional microfluidic chips. To validate the microfluidic system, samples of P. falciparum-infected red blood cell cultures were used. The SERS-based immunoassay enabled the detection of 0.0012 ± 0.0001% parasitaemia in a P. falciparum-infected red blood cell culture supernatant, an ∼7-fold higher sensitivity than that attained by most rapid diagnostic tests. Our approach successfully overcomes the main challenges of the current Plasmodium detection methods, including increased reproducibility, sensitivity, and specificity. Furthermore, our system can be easily adapted for detection of other pathogens and has excellent properties for early diagnosis of infectious diseases, a decisive step towards lowering their high burden on healthcare systems worldwide. [ABSTRACT FROM AUTHOR]

Advanced light management via front‐coated photonic nanostructures is a promising strategy to enhance photovoltaic (PV) efficiency through wave‐optical light‐trapping (LT) effects, avoiding the conventional texturing processes that induce the degradation of electrical performance due to increased carrier recombination. Titanium dioxide (TiO2) honeycomb arrays with different geometry are engineered through a highly‐scalable colloidal lithography method on flat crystalline silicon (c‐Si) wafers and tested on standard planar c‐Si interdigitated back‐contact solar cells (pIBCSCs). The photonic‐structured wafers achieve an optical photocurrent of 36.6 mA cm−2, mainly due to a broad anti‐reflection effect from the 693 nm thick nanostructured coatings. In contrast, the pIBCSC test devices reach 14% efficiency with 679 nm thick TiO2 nanostructures, corresponding to a ≈30% efficiency gain relative to uncoated pIBCSCs. In addition, several designed structures show unmatched angular acceptance enhancements in efficiency (up to 63% gain) and photocurrent density (up to 68% gain). The high‐performing (yet electrically harmless) LT scheme, here presented, entails an up‐and‐coming alternative to conventional texturing for c‐Si technological improvement that can be straightforwardly integrated into the established PV industry. [ABSTRACT FROM AUTHOR]

An overview of the last trends in lab-on-chip technology highlights the continuous development of biosensing approaches in terms of simplicity, low-cost, and quick response, with a higher sensitivity and selectivity. In this context, electrochemical sensors arrived to overcome the need to develop small, accurate, portable and compact sensing devices, compatible with routine use in loco analysis, especially in point-of-care (POC) assessment. Herein, we have presented the first paper-based electrochemical sensor towards the detection of 3-nitrotyrosine (3-NT), a relevant oxidative stress biomarker. This innovative sensor was designed by, first, modifying paper to become a hydrophobic support and, second applying carbon and silver conductive inks to generate a three electrode-system on a small spot. An intensive voltammetric investigation of the paper-based screen-printed electrodes (SPEs), including the study of different redox-probes, scan-rate values, probe concentrations and supporting electrolyte solutions, confirmed their suitable and reliable electrochemical performance. Square wave voltammetry (SWV) was employed to assess the sensitivity of the proposed sensor at various concentrations of 3-NT, ranging from 500 nM to 1 mM, enabling a low detection limit (LOD) of 49.2 nM. The interference of co-existing species was also tested and good selectivity against 3-NT was accomplished. Overall, this flexible paper-based platform constitutes a promising sensor material towards a quick, sensitive, cost-effective, sustainable and reproducible detection of 3-NT biomarker. [ABSTRACT FROM AUTHOR]

Droplet-based microfluidic technology is a powerful tool for generating large numbers of monodispersed nanoliter-sized droplets for ultra-high throughput screening of molecules or single cells. Yet further progress in the development of methods for the real-time detection and measurement of passing droplets is needed for achieving fully automated systems and ultimately scalability. Existing droplet monitoring technologies are either difficult to implement by non-experts or require complex experimentation setups. Moreover, commercially available monitoring equipment is expensive and therefore limited to a few laboratories worldwide. In this work, we validated for the first time an easy-to-use, open-source Bonsai visual programming language to accurately measure in real-time droplets generated in a microfluidic device. With this method, droplets are found and characterized from bright-field images with high processing speed. We used off-the-shelf components to achieve an optical system that allows sensitive image-based, label-free, and cost-effective monitoring. As a test of its use we present the results, in terms of droplet radius, circulation speed and production frequency, of our method and compared its performance with that of the widely-used ImageJ software. Moreover, we show that similar results are obtained regardless of the degree of expertise. Finally, our goal is to provide a robust, simple to integrate, and user-friendly tool for monitoring droplets, capable of helping researchers to get started in the laboratory immediately, even without programming experience, enabling analysis and reporting of droplet data in real-time and closed-loop experiments. [ABSTRACT FROM AUTHOR]

Microfluidic-based platforms have become a hallmark for chemical and biological assays, empowering micro- and nano-reaction vessels. The fusion of microfluidic technologies (digital microfluidics, continuous-flow microfluidics, and droplet microfluidics, just to name a few) presents great potential for overcoming the inherent limitations of each approach, while also elevating their respective strengths. This work exploits the combination of digital microfluidics (DMF) and droplet microfluidics (DrMF) on a single substrate, where DMF enables droplet mixing and further acts as a controlled liquid supplier for a high-throughput nano-liter droplet generator. Droplet generation is performed at a flow-focusing region, operating on dual pressure: negative pressure applied to the aqueous phase and positive pressure applied to the oil phase. We evaluate the droplets produced with our hybrid DMF–DrMF devices in terms of droplet volume, speed, and production frequency and further compare them with standalone DrMF devices. Both types of devices enable customizable droplet production (various volumes and circulation speeds), yet hybrid DMF–DrMF devices yield more controlled droplet production while achieving throughputs that are similar to standalone DrMF devices. These hybrid devices enable the production of up to four droplets per second, which reach a maximum circulation speed close to 1540 µm/s and volumes as low as 0.5 nL. [ABSTRACT FROM AUTHOR]

Poly(p-xylylene) derivatives, widely known as Parylenes, have been considerably adopted by the scientific community for several applications, ranging from simple passive coatings to active device components. Here, we explore the thermal, structural, and electrical properties of Parylene C, and further present a variety of electronic devices featuring this polymer: transistors, capacitors, and digital microfluidic (DMF) devices. We evaluate transistors produced with Parylene C as a dielectric, substrate, and encapsulation layer, either semitransparent or fully transparent. Such transistors exhibit steep transfer curves and subthreshold slopes of 0.26 V/dec, negligible gate leak currents, and fair mobilities. Furthermore, we characterize MIM (metal–insulator–metal) structures with Parylene C as a dielectric and demonstrate the functionality of the polymer deposited in single and double layers under temperature and AC signal stimuli, mimicking the DMF stimuli. Applying temperature generally leads to a decrease in the capacitance of the dielectric layer, whereas applying an AC signal leads to an increase in said capacitance for double-layered Parylene C only. By applying the two stimuli, the capacitance seems to suffer from a balanced influence of both the separated stimuli. Lastly, we demonstrate that DMF devices with double-layered Parylene C allow for faster droplet motion and enable long nucleic acid amplification reactions. [ABSTRACT FROM AUTHOR]

Digital Microfluidics (DMF) has emerged as a disruptive methodology for the control and manipulation of low volume droplets. In DMF, each droplet acts as a single reactor, which allows for extensive multiparallelization of biological and chemical reactions at a much smaller scale. DMF devices open entirely new and promising pathways for multiplex analysis and reaction occurring in a miniaturized format, thus allowing for healthcare decentralization from major laboratories to point-of-care with accurate, robust and inexpensive molecular diagnostics. Here, we shall focus on DMF platforms specifically designed for nucleic acid amplification, which is key for molecular diagnostics of several diseases and conditions, from pathogen identification to cancer mutations detection. Particular attention will be given to the device architecture, materials and nucleic acid amplification applications in validated settings. [ABSTRACT FROM AUTHOR]

An innovative biosensor assembly relying on a simple and straightforward in-situ construction is presented to monitor urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) down to the pmol/L level. The sensing film of the biosensor consisted of a molecularly imprinted polymer (MIP) layer for 8-OHdG assembled on a gold electrode through electropolymerization of monomer combined with the template. The analytical features of the resulting biosensor were assessed by Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). Some experimental parameters such as the initial concentration of the monomer and the ratio template-monomer were investigated and optimized in order to finely tune the performance of the MIP-based sensor. Under optimal conditions, the developed biosensor was able to rebind 8-OHdG with a linear response against EIS from 0.1 to 100 pg/ml 3.5-3500 pM. The interference of coexisting species was tested, also with calibrations on urine samples, and good selectivity towards 8-OHdG was obtained. RAMAN spectroscopy, FTIR and SEM evaluations of the prepared films confirmed the formation of a polyphenol thin-film on the electrode surface. The presence and distribution of the imprinted cavities on the MIP layer was confirmed by confocal microscopy imaging of the film, after a post-treatment with Fluorescein Isothiocyanate (FITC) labeled 8-OHdG antibody. Overall, this label-free biosensor for urinary 8-OHdG detection constitutes a promising low-cost alternative to the conventional immunoassay approaches, due to its simplicity, stability, high sensitivity and selectivity for biological sample assays, opening new doors for other applications. [ABSTRACT FROM AUTHOR]

Background: Diabetes is a heterogeneous and multifactorial disease. However, glycemia and glycated hemoglobin have been the focus of diabetes diagnosis and management for the last decades. As diabetes management goes far beyond glucose control, it has become clear that assessment of other biochemical parameters gives a much wider view of the metabolic state of each individual, enabling a precision medicine approach. Methods: In this review, we summarize and discuss indexes that have been used in epidemiological studies and in the clinical practice. Results: Indexes of insulin secretion, sensitivity/resistance and metabolism have been developed and validated over the years to account also with insulin, C‐peptide, triglycerides or even anthropometric measures. Nevertheless, each one has their own objective and consequently, advantages and disadvantages for specific cases. Thus, we discuss how new technologies, namely new sensors but also new softwares/applications, can improve the diagnosis and management of diabetes, both for healthcare professionals but also for caretakers and, importantly, to promote the empowerment of people living with diabetes. Conclusions: In long‐term, the solution for a better diabetes management would be a platform that allows to integrate all sorts of relevant information for the person with diabetes and for the healthcare practitioners, namely glucose, insulin and C‐peptide or, in case of need, other parameters/indexes at home, sometimes more than once a day. This solution would allow a better and simpler disease management, more adequate therapeutics thereby improving patients' quality of life and reducing associated costs. [ABSTRACT FROM AUTHOR]

The preparation of visible-light-driven photocatalysts has become highly appealing for environmental remediation through simple, fast and green chemical methods. The current study reports the synthesis and characterization of graphitic carbon nitride/titanium dioxide (g-C3N4/TiO2) heterostructures through a fast (1 h) and simple microwave-assisted approach. Different g-C3N4 amounts mixed with TiO2 (15, 30 and 45 wt. %) were investigated for the photocatalytic degradation of a recalcitrant azo dye (methyl orange (MO)) under solar simulating light. X-ray diffraction (XRD) revealed the anatase TiO2 phase for the pure material and all heterostructures produced. Scanning electron microscopy (SEM) showed that by increasing the amount of g-C3N4 in the synthesis, large TiO2 aggregates composed of irregularly shaped particles were disintegrated and resulted in smaller ones, composing a film that covered the g-C3N4 nanosheets. Scanning transmission electron microscopy (STEM) analyses confirmed the existence of an effective interface between a g-C3N4 nanosheet and a TiO2 nanocrystal. X-ray photoelectron spectroscopy (XPS) evidenced no chemical alterations to both g-C3N4 and TiO2 at the heterostructure. The visible-light absorption shift was indicated by the red shift in the absorption onset through the ultraviolet-visible (UV-VIS) absorption spectra. The 30 wt. % of g-C3N4/TiO2 heterostructure showed the best photocatalytic performance, with a MO dye degradation of 85% in 4 h, corresponding to an enhanced efficiency of almost 2 and 10 times greater than that of pure TiO2 and g-C3N4 nanosheets, respectively. Superoxide radical species were found to be the most active radical species in the MO photodegradation process. The creation of a type-II heterostructure is highly suggested due to the negligible participation of hydroxyl radical species in the photodegradation process. The superior photocatalytic activity was attributed to the synergy of g-C3N4 and TiO2 materials. [ABSTRACT FROM AUTHOR]

A correction to the article "Thin-film transistors based on p-type Cu22O thin films produced at room temperatures" that was published in the letters 96, 19210 in 2010 issue is presented.

Polymer material provides significant advantages over the conventional inorganic material-based electronics due to its attractive features including miniaturized dimension and feasible improvisations in physical properties through molecular design and chemical synthesis. In particular, conjugate polymers are of great interest because of their ability to control the energy gap and electronegativity through molecular design that has made possible the synthesis of conducting polymers with a range of ionization potentials and electron affinities. Polyaniline (PANI) is one of the most popular conjugated polymers that has been widely explored so far for its multifunctionality in diverse potential applications. This review is focusing on the recent advances of PANI for smart energy applications including supercapacitors, batteries, solar cells and nanogenerators and the development in its synthesis, design, and fabrication processes. A details investigation on the different types of chemical process has been discussed to fabricate PANI in nanostructures, film, and composites form. The paper includes several studies which are advantageous for understanding: the unique chemical and physical properties of this polymer; and the easily tunable electrical properties along with its redox behavior; and different processes to develop nanostructures, film, or bulk form of PANI that are useful to derive its applicability in smart objects or devices. Polyaniline can be fabricated and engineered in different forms (bulk-nanostructures-nanocomposites) via variety of synthesis techniques while having unique properties to be used in smart energy applications. [Display omitted] • Description of different synthesis methods for polyaniline and its composites. • Enlightens a wide range of knowledge, research progress and scope of polyaniline based smart energy applications. • Polyaniline as a new emerging material for mechanical energy harvester [ABSTRACT FROM AUTHOR]

Two di-ureasils incorporating oxyethylene segments with average molecular weights Y = 600 and 900 g mol−1, prepared by the sol-gel method, and doped with the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and lithium tetrafluoroborate (LiBF4) salt were prepared. The as-obtained films are translucent, flexible, and hydrophobic, and have a low level of nanoscale surface roughness. The ionic conductivity values exhibited by an optimized sample are 8.10 × 10−5 and 2.8 × 10−4 S cm−1 at room temperature and 55 °C, respectively. The main goal of the work was to employ the electrolytes in prototype electrochromic devices (ECDs) with the [glass/a-IZO/a-WO3/d-U(Y)LiBF4-[Bmim]Cl/c-NiO/a-IZO/glass], noted as ECD1 for Y = 600 and ECD2 for Y = 900, where a-WO3 and c-NiO stand for amorphous tungsten oxide and crystalline nickel oxide, respectively. At 555 nm the ECD1 device exhibited the highest coloration efficiency for coloring (CEin = −420.621 cm2·C−1), the highest optical density value (∆(OD) = 0.13) and good cycling stability. In this article, the results of a preliminary evaluation of hybrid electrolytes, produced by a sol-gel process, as multi-functional components in prototype electrochromic devices are reported. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) is as a promising material for flexible microsupercapacitors (MSCs) due to its simple and cost-effective processing. However, LIG-MSC research and production has been centered on non-sustainable polymeric substrates, such as polyimide. In this work, it is presented a cost-effective, reproducible, and robust approach for the preparation of LIG structures via a one-step laser direct writing on chromatography paper. The developed strategy relies on soaking the paper in a 0.1 M sodium tetraborate solution (borax) prior to the laser processing. Borax acts as a fire-retardant agent, thus allowing the laser processing of sensitive substrates that other way would be easily destroyed under the high-energy beam. LIG on paper exhibiting low sheet resistance (30 Ω sq−1) and improved electrode/electrolyte interface was obtained by the proposed method. When used as microsupercapacitor electrodes, this laser-induced graphene resulted in specific capacitances of 4.6 mF cm−2 (0.015 mA cm−2). Furthermore, the devices exhibit excellent cycling stability (> 10,000 cycles at 0.5 mA cm−2) and good mechanical properties. By connecting the devices in series and parallel, it was also possible to control the voltage and energy delivered by the system. Thus, paper-based LIG-MSC can be used as energy storage devices for flexible, low-cost, and portable electronics. Additionally, due to their flexible design and architecture, they can be easily adapted to other circuits and applications with different power requirements. [ABSTRACT FROM AUTHOR]

Since the discovery of laser-induced graphene (LIG), significant advances have been made to obtain green LIG (gLIG) from abundant, eco-friendly, natural, and organic renewable bio-based carbon sources. Recently, some sustainable and cost-effective electronic devices have been designed with gLIG, resulting in diverse solutions to the environmental impact caused by electronic waste (e-waste). However, there are still several challenges that must be addressed regarding the widespread market implementation of gLIG-based products, from synthesis to practical applications. In this review, we focus on sustainable precursor sources, their conversion mechanisms, physical and chemical properties and applications, along with the challenges related to its implementation, showing the future opportunities and perspectives related to this promising new material. Various systems based on gLIG for energy storage, electrocatalysis, water treatment, and sensors have been reported in the literature. Additionally, gLIG has been proposed for ink formulation or incorporation into polymer matrices, to further expand its use to non-carbon-based substrates or applications for which pristine LIG cannot be directly used. In this way, it is possible to apply gLIG on diverse substrates, aiming at emerging wearable and edible electronics. Thus, this review will bring an overview of gLIG developments, in accordance with the European Green Deal, the United Nations Sustainable Development Goals and the new era of internet-of-things, which demands cost-effective electronic components based on the principles of energy efficiency and sustainable production methods. [ABSTRACT FROM AUTHOR]

FucoPol is an acylated polysaccharide with demonstrated valuable functional properties that include a shear thinning fluid behaviour, a film-forming capacity, and an emulsion forming and stabilizing capacity. In this study, the different conditions (concentration, temperature, and time) for alkaline treatment were investigated to deacylate FucoPol. Complete deacetylation and desuccinylation was achieved with 0.02 M NaOH, at 60 °C for 15 min, with no significant impact on the biopolymer's sugar composition, pyruvate content, and molecular mass distribution. FucoPol depyruvylation by acid hydrolysis was attempted, but it resulted in a very low polymer recovery. The effect of the ionic strength, pH, and temperature on the deacetylated/desuccinylated polysaccharide, d-FucoPol, was evaluated, as well as its emulsion and film-forming capacity. d-FucoPol aqueous solutions maintained the shear thinning behaviour characteristic of FucoPol, but the apparent viscosity decreased significantly. Moreover, contrary to FucoPol, whose solutions were not affected by the media's ionic strength, the d-FucoPol solutions had a significantly higher apparent viscosity for a higher ionic strength. On the other hand, the d-FucoPol solutions were not affected by the pH in the range of 3.6–11.5, while FucoPol had a decreased viscosity for acidic pH values and for a pH above 10.5. Although d-FucoPol displayed an emulsification activity for olive oil similar to that of FucoPol (98 ± 0%) for an oil-to-water ratio of 2:3, the emulsions were less viscous. The d-FucoPol films were flexible, with a higher Young′s modulus (798 ± 152 MPa), a stress at the break (22.5 ± 2.5 MPa), and an elongation at the break (9.3 ± 0.7%) than FucoPol (458 ± 32 MPa, 15.5 ± 0.3 MPa and 8.1 ± 1.0%, respectively). Given these findings, d-FucoPol arises as a promising novel biopolymer, with distinctive properties that may render it useful for utilization as a suspending or emulsifier agent, and as a barrier in coatings and packaging films. [ABSTRACT FROM AUTHOR]

This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (ΔEab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7–6.1 × 10−11 mol m−1 s−1 Pa−1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (ε) (35.6–47.0%), low tensile strength at break (Ꞇ) (4.55–11.7 MPa) and low Young's modulus (εm) (10–93 MPa), whereas the other three were stiffer and more resistant with a higher Ꞇ (16.6–23.6 MPa), lower ε (2.80–5.58%), and higher εm (597–1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging. [ABSTRACT FROM AUTHOR]

The inexorable increase of energy demand and the efficiency bottleneck of monocrystalline silicon solar cell technology is promoting the research and development of alternative photovoltaic materials. Copper-arsenic-sulfide (CAS) compounds are still rather unexplored in the literature, yet they have been regarded as promising candidates for use as p-type absorber in solar cells, owing to their broad raw material availability, suitable bandgap and high absorption coefficient. Here, a comprehensive study is presented on the structural and optoelectronic properties of CAS thin-films deposited via radio-frequency magnetron co-sputtering, using a commercial Cu target together with a Cu-As-S target with material obtained from local resources, specifically from mines in the Portuguese region of the Iberian Pyrite Belt. Raman and X-ray diffraction analysis confirm that the use of two targets results in films with pronounced stoichiometry gradients, suggesting a transition from amorphous CAS compounds to crystalline djurleite (Cu31S16), with the increasing proximity to the Cu target. Resistivity values from 4.7 mΩ·cm to 17.4 Ω·cm are obtained, being the lowest resistive films, those with pronounced sub-bandgap free-carrier absorption. The bandgap values range from 2.20 to 2.65 eV, indicating promising application as wide-bandgap semiconductors in third-generation (e.g., multi-junction) photovoltaic devices. [ABSTRACT FROM AUTHOR]

The present study is focused on the synthesis of zirconium dioxide (ZrO2) nanomaterials using the hydrothermal method assisted by microwave irradiation and solution combustion synthesis. Both synthesis techniques resulted in ZrO2 powders with a mixture of tetragonal and monoclinic phases. For microwave synthesis, a further calcination treatment at 800 °C for 15 min was carried out to produce nanopowders with a dominant monoclinic ZrO2 phase, as attested by X-ray diffraction (XRD) and Raman spectroscopy. The thermal behavior of the ZrO2 nanopowder was investigated by in situ XRD measurements. From the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images, the presence of near spherical nanoparticles was clear, and TEM confirmed the ZrO2 phases that comprised the calcinated nanopowders, which include a residual tetragonal phase. The optical properties of these ZrO2 nanopowders were assessed through photoluminescence (PL) and PL excitation (PLE) at room temperature (RT), revealing the presence of a broad emission band peaked in the visible spectral region, which suffers a redshift in its peak position, as well as intensity enhancement, after the calcination treatment. The powder resultant from the solution combustion synthesis was composed of plate-like structures with a micrometer size; however, ZrO2 nanoparticles with different shapes were also observed. Thin films were also produced by solution combustion synthesis and deposited on silicon substrates to produce energy storage devices, i.e., ZrO2 capacitors. The capacitors that were prepared from a 0.2 M zirconium nitrate-based precursor solution in 2-methoxyethanol and annealed at 350 °C exhibited an average dielectric constant (κ) of 11 ± 0.5 and low leakage current density of 3.9 ± 1.1 × 10−7 A/cm2 at 1 MV/cm. This study demonstrates the simple and cost-effective aspects of both synthesis routes to produce ZrO2 nanomaterials that can be applied to energy storage devices, such as capacitors. [ABSTRACT FROM AUTHOR]

Laser-induced graphene from paper (paper-LIG) was applied in non-enzymatic electrochemical sensing of uric acid (UA) in human urine. Paper-LIG was formed by CO 2 laser modification of paper into a 3D graphene arrangement. Kinetic analysis of paper-LIG electrodes returned effective heterogeneous electron transfer standard rate constants of 1.4 × 10−3 cm s−1 and 7.8 × 10−4 cm s−1 for [Ru(NH 3) 6 ]2+/3+ and [Fe(CN) 6 ]4−/3− redox probes, respectively. These electrodes were able to detect and quantify uric acid in PBS within the 10–300 μM range at pH between 5.6 and 7.4. At pH 7.4, a linear response (R2 = 0.999) from 10 to 250 μM was achieved, with a limit of detection of 3.97 μM and a sensitivity of 0.363 μA cm−2 μM−1. Paper-LIG electrodes denoted adequate selectivity in synthetic urine as well as in ascorbic acid (AA) and dopamine (DA)-containing electrolytes. Determination of urinary UA content in human samples returned a concentration of c.a. 1.8–1.9 mM, within the range for healthy individuals. Recoveries of samples spiked with 50 and 100 μM UA were 100.6% and 95.4%, respectively, with satisfactory reproducibility and stability. These cheap, lightweight, flexible, and eco-friendly paper-LIG biosensors for non-enzymatic quantification of UA in human urine pave the way to widespread application in the detection of other important biomarkers. [Display omitted] • "Green" graphene electrodes by CO 2 laser irradiation of paper ("paper-LIG"). • Uric acid (UA) quantification at clinically relevant concentrations and pH (5.6–7.4). • Limit of detection of 3.97 μM and a sensitivity of 0.363 μA cm−2 μM−1 (pH = 7.4). • Adequate selectivity in synthetic urine, as well as in ascorbic acid and dopamine-containing electrolytes. • Recoveries of 100.6% and 95.4% for human urine samples spiked with 50 and 100 μM UA. [ABSTRACT FROM AUTHOR]

Encapsulins are protein nanocages capable of harboring smaller proteins (cargo proteins) within their cavity. The function of the encapsulin systems is related to the encapsulated cargo proteins. The Myxococcus xanthus encapsulin (EncA) naturally encapsulates ferritin-like proteins EncB and EncC as cargo, resulting in a large iron storage nanocompartment, able to accommodate up to 30,000 iron atoms per shell. In the present manuscript we describe the binding and protection of circular double stranded DNA (pUC19) by EncA using electrophoretic mobility shift assays (EMSA), atomic force microscopy (AFM), and DNase protection assays. EncA binds pUC19 with an apparent dissociation constant of 0.3 ± 0.1 µM and a Hill coefficient of 1.4 ± 0.1, while EncC alone showed no interaction with DNA. Accordingly, the EncAC complex displayed a similar DNA binding capacity as the EncA protein. The data suggest that initially, EncA converts the plasmid DNA from a supercoiled to a more relaxed form with a beads-on-a-string morphology. At higher concentrations, EncA self-aggregates, condensing the DNA. This process physically protects DNA from enzymatic digestion by DNase I. The secondary structure and thermal stability of EncA and the EncA−pUC19 complex were evaluated using synchrotron radiation circular dichroism (SRCD) spectroscopy. The overall secondary structure of EncA is maintained upon interaction with pUC19 while the melting temperature of the protein (Tm) slightly increased from 76 ± 1 °C to 79 ± 1 °C. Our work reports, for the first time, the in vitro capacity of an encapsulin shell to interact and protect plasmid DNA similarly to other protein nanocages that may be relevant in vivo. [ABSTRACT FROM AUTHOR]

Indium oxide (In2O3)-based transparent conducting oxides (TCOs) have been widely used and studied for a variety of applications, such as optoelectronic devices. However, some of the more promising dopants (zirconium, hafnium, and tantalum) for this oxide have not received much attention, as studies have mainly focused on tin and zinc, and even fewer have been explored by solution processes. This work focuses on developing solution-combustion-processed hafnium (Hf)-doped In2O3 thin films and evaluating different annealing parameters on TCO's properties using a low environmental impact solvent. Optimized TCOs were achieved for 0.5 M% Hf-doped In2O3 when produced at 400 °C, showing high transparency in the visible range of the spectrum, a bulk resistivity of 5.73 × 10−2 Ω.cm, a mobility of 6.65 cm2/V.s, and a carrier concentration of 1.72 × 1019 cm−3. Then, these results were improved by using rapid thermal annealing (RTA) for 10 min at 600 °C, reaching a bulk resistivity of 3.95 × 10 −3 Ω.cm, a mobility of 21 cm2/V.s, and a carrier concentration of 7.98 × 1019 cm−3, in air. The present work brings solution-based TCOs a step closer to low-cost optoelectronic applications. [ABSTRACT FROM AUTHOR]

Laser‐induced graphene (LIG) produced by irradiation of paper (paper‐LIG)holds substantial promise for flexible devices. This article presents paper‐LIG humidity and temperature sensors fabricated by single‐step irradiation of common filter paper with a pulsed UV laser (355 nm). The influence of the process parameters on the conversion of cellulose fibers into LIG is discussed based on the resulting morphology, structure, conductivity, and chemical composition, revealing a distinct barrier to transformation and a propagation behavior not seen under CO2 laser irradiation. The obtained material is constituted by a porous, electrically conductive network of fibers. The paper‐LIG relative humidity (RH) and temperature sensors with sensitivities of up to 1.3 × 10−3%RH−1 and ‐ 2.8 × 10−3 °C−1, respectively, are examined in terms of their linearity, reproducibility, and response time. A detailed discussion on the response mechanism is presented in the context of literature, pointing towards the absorption of water molecules in the interlayer spacing of graphene as the main reason for the increase in resistance with RH. Additionally, a contribution from variable range hopping along the ab plane of graphene at high RH is suggested. These results demonstrate the potential of paper‐LIG for low‐cost, sustainable, and environmentally friendly sensing. [ABSTRACT FROM AUTHOR]

The contamination of water resources by pollutants resulting from human activities represents a major concern nowadays. One promising alternative to solve this problem is the photocatalytic process, which has demonstrated very promising and efficient results. Oxide nanostructures are interesting alternatives for these applications since they present wide band gaps and high surface areas. Among the photocatalytic oxide nanostructures, zinc tin oxide (ZTO) presents itself as an eco-friendly alternative since its composition includes abundant and non-toxic zinc and tin, instead of critical elements. Moreover, ZTO nanostructures have a multiplicity of structures and morphologies possible to be obtained through low-cost solution-based syntheses. In this context, the current work presents an optimization of ZTO nanostructures (polyhedrons, nanoplates, and nanoparticles) obtained by microwave irradiation-assisted hydrothermal synthesis, toward photocatalytic applications. The nanostructures' photocatalytic activity in the degradation of rhodamine B under both ultraviolet (UV) irradiation and natural sunlight was evaluated. Among the various morphologies, ZTO nanoparticles revealed the best performance, with degradation > 90% being achieved in 60 min under UV irradiation and in 90 min under natural sunlight. The eco-friendly production process and the demonstrated ability of these nanostructures to be used in various water decontamination processes reinforces their sustainability and the role they can play in a circular economy. [ABSTRACT FROM AUTHOR]

In 2 S 3 / branched TiO 2 nanorods (br-TiO 2) heterostructure was prepared by a simple route using three-step methods as a visible and solar light photocatalyst for water treatment applications. Structural properties have been carried out by X-ray diffraction and Raman spectroscopy. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and atomic force microscopy has been used to determine the morphology and the surface roughness of samples. The In 2 S 3 / br-TiO 2 heterojunction confirm the presence of both structures of Rutile TiO 2 and cubic β-In 2 S 3. Optical results showed that the heterojunction exhibited increased absorption ability in the visible light, indicating an increased photoactivity for In 2 S 3 / br-TiO 2 in the visible light. Wettability studies reveal that In 2 S 3 / br-TiO 2 film is superhydrophilic with water contact angle of 0°. Photocatalytic activity of heterojunction In 2 S 3 / br-TiO 2 was assessed with remarkable degradability performance of 85% after 80 min under solar irradiation. The reusability test highlighted that the In 2 S 3 / br-TiO 2 still maintained high photocatalytic activity over five cycles. The photoelectrochemical activity was evaluated. The results showed the successful development of In 2 S 3 / br-TiO 2 heterostructure with better photoactivity properties. The In 2 S 3 / br-TiO 2 electrode achieved remarkably improved current density (0.59 mA.cm2 at 0.6 V vs Ag/AgCl) compared to br-TiO 2 and In 2 S 3. These results reveal that In 2 S 3 / br-TiO 2 thin films being excellent photoactivity along with its superhydrophilic nature which it is possesses great potential toward the development of newly synthesizable catalysts in the field of water purification. • br-TiO 2 , In 2 S 3 , In 2 S 3 / br-TiO 2 thin films were prepared by a cost-effective hydrothermal method and chemical bath deposition • Excellent light harvesting capabilities of In 2 S 3 br-TiO 2 heterostructure • In 2 S 3 / br-TiO 2 thin films show superhydrophilic character • High performance photocatalytic activity of heterostructure up to 85% after 80 min under solar irradiation. • The PEC performance of In 2 S 3 / br-TiO 2 is greatly improved compared to those of br-TiO 2 and In 2 S 3. [ABSTRACT FROM AUTHOR]

In this study, polyethylene glycol-modified titanium dioxide (PEG-modified TiO2) nanopowders were prepared using a fast solvothermal method under microwave irradiation, and without any further calcination processes. These nanopowders were further impregnated on porous polymeric platforms by drop-casting. The effect of adding iron with different molar ratios (1, 2, and 5%) of iron precursor was investigated. The characterization of the produced materials was carried out by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Optical characterization of all the materials was also carried out. SEM showed that pure TiO2 and Fe-TiO2 nanostructures presented similar nanosized and spherical particles, which uniformly covered the substrates. From XRD, pure TiO2 anatase was obtained for all nanopowders produced, which was further confirmed by Raman spectroscopy on the impregnated substrates. XPS and UV–VIS absorption spectroscopy emission spectra revealed that the presence of Fe ions on the Fe-TiO2 nanostructures led to the introduction of new intermediate energy levels, as well as defects that contributed to an enhancement in the photocatalytic performance. The photocatalytic results under solar radiation demonstrated increased photocatalytic activity in the presence of the 5% Fe-TiO2 nanostructures (Rhodamine B degradation of 85% after 3.5 h, compared to 74% with pure TiO2 for the same exposure time). The photodegradation rate of RhB dye with the Fe-TiO2 substrate was 1.5-times faster than pure TiO2. Reusability tests were also performed. The approach developed in this work originated novel functionalized photocatalytic platforms, which were revealed to be promising for the removal of organic dyes from wastewater. [ABSTRACT FROM AUTHOR]