Synergistic design of processable Nb2O5-TiO2 bilayer nanoarchitectonics: enabling high coloration efficiency and superior stability in dual-band electrochromic energy storage.

This paper introduces a proof of concept for a dual-band electrochromic (EC) device to modulate solar light transmission across visible and near-infrared regions selectively. EC materials based on ion insertion/extraction mechanisms also present the possibility for energy storage, widening its functionality to the supercapacitor platform. The bi-functional performance of dual-band radiation control and energy storage was achieved by exploiting two earth-abundant metal oxides that could absorb two different spectral regions when electrochemically charged. The bilayer structure was prepared using a one-step hydrothermal method, which produced Nb2O5-TiO2 bilayer on fluorine-doped tin oxide (FTO) conducting glass substrates. The nano-dimensions of the active materials endorse the development of high-transparency thin film under open circuit conditions. The variations in the TiO2 annealing temperature influence the crystallinity and surface morphology of the thin films, which influence the performance of dual-band EC energy storage. The well-optimized NT-500 sample facilitated exclusive electron-charge transport, producing excellent electrochemical performance in dual-band EC and energy storage. A large optical modulation of 80.4 % and 89.8 % at 600 nm and 800 nm (near-infrared) was achieved with an enhanced areal capacitance of 88.1 mF/cm2 and excellent cycling stability after continuous coloring/bleaching cycles for 18,000 s. This paper presents a prototype bi-functional device based on NT-500, which showed independent control and modulation of visible and near-infrared transmittance. Notably, the device retained excellent energy storage performance alongside its advanced optical functionalities. This bilayer nanostructure capitalizes on the inherent electrochemical properties of both materials and introduces novel features that can potentially revolutionize the platform of EC-energy storage.

Plasmonic group IVB transition metal nitrides: Fabrication methods and applications in biosensing, photovoltaics and photocatalysis.

This review paper focuses on group IVB transition metal nitrides (TMNs) such as titanium nitride (TiN), zirconium nitride (ZrN), and hafnium nitride (HfN) and as alternative plasmonic materials to noble metals like gold and silver. It delves into the fabrication methods of these TMNs, particularly emphasizing thin film fabrication techniques like magnetron sputtering and atomic layer deposition, as well as nanostructure fabrication processes applied to these thin films. Overcoming the current fabrication and application-related challenges requires a deep understanding of the material properties, deposition techniques, and application requirements. Here, we discuss the impact of fabrication parameters on the properties of resulting films, highlighting the importance of aligning fabrication methods with practical application requirements for optimal performance. Additionally, we summarize and tabulate the most recent plasmonic applications of these TMNs in fields like biosensing, photovoltaic energy, and photocatalysis, contributing significantly to the current literature by consolidating knowledge on TMNs.

Role of growth temperature on microstructural and electronic properties of rapid thermally grown MoTe2 thin film for IR detection.

In the field of electronic and optoelectronic applications, two-dimensional materials are found to be the promising candidates for futuristic devices. For the detection of infrared light, MoTe2 possesses an appropriate bandgap for which p-MoTe2/n-Si heterojunctions are suits well for photodetectors. In this study, rapid thermal technique is used to grow MoTe2 thin films on silicon (Si) substrates. Molybdenum (Mo) thin films were deposited using sputtering system on Si substrate and Tellurium (Te) film was deposited on Mo film by thermal evaporation technique. The substrates with Mo/Te thin films are kept in a face-to-face manner inside the RTP furnace. The growth was carried out at a base pressure of 2 torr with the flow of 160 sccm argon gas at different temperatures ranging from 400 °C to 700 °C. The XRD peaks appeared around 2θ = 12.8°, 25.5°, 39.2°, 53.2° corresponding to (002), (004), (006) and (008) orientation of hexagonal 2H-MoTe2 structure. The characteristic Raman peaks of MoTe2,observed at ~119 cm-1 and ~172 cm-1,corresponds to in-plane E1g and out-of-plane A1g mode of MoTe2, whereas the prominent peaks of the in-plane E12g mode at ∼234 cm-1, and the out-of-plane B12g mode at ∼289 cm-1 are also observed. RMS roughness is found to be increasing with increasing growth temperature. The bandgap of MoTe2 is calculated using Tauc plot and found to be 0.91 eV. Electrical characterizations are carried out using current-voltage and current-time measurement, where the maximum responsivity and detectivity are found to be 127.37 mA/W and 85.21 × 107 Jones for growth temperature of 600 °C and IR wavelength illumination of 1060 nm. .

Sensing Interfaces Engineering for Organic Thin Film Transistors-Based Biosensors: Opportunities and Challenges.

Organic thin film transistors (OTFTs) enable rapid and label-free high-sensitivity detection of target analytes due to their low cost, large-area processing, biocompatibility, and inherent signal amplification. At the same time, the freedom of synthesis, tailorability, and functionalization of organic semiconductor materials and their ability to be combined with flexible substrates make them one of the ideal platforms for biosensing. However, OTFTs-based biosensors still face significant challenges, such as unexpected surface adsorption, disordered conformation, inhomogeneous graft density, and flexibility of probe molecules that biological sensing probes would face during immobilization. In this review, efficient immobilization strategies based on OTFTs biological sensing probes developed in the last 5 years are highlighted. First, the biosensors are classified according to their sensing interface. Second, a comprehensive discussion of the types of biological sensing probes is presented. Third, three commonly used methods for immobilizing biological sensing probes and their challenges are briefly described. Finally, the applications of OTFTs-based biosensors for liquid phase detection are summarized. This review provides a comprehensive and timely review of optimization in sensing interface engineering so that efficient immobilization of biological sensing probes with sensing interfaces will contribute to the development of high-performance OTFTs-based biosensors.

Optimization of the determination of volatile organic compounds in plant tissue and soil samples: Untargeted metabolomics of main active compounds.

This review critically assesses the determination of low molecular weight volatiles by different methods, providing context for the development of suitable techniques to determine volatile content in plant tissue and soil samples as well as the associated analytical challenges. Although sensitive analytical methods have been reported in recent decades, studies on their application in modern investigative techniques are lacking. Herein, the latest sampling methods in volatile biochemistry, current advancements in the understanding of these analytes, and the significance of these findings for other types of volatiles are summarized. Gas chromatography, high-performance liquid chromatography, ion chromatography, thin-film microextraction, and real-time monitoring techniques are discussed and critically determined. This review concerns the methods most suitable for future research in this area.

Enhanced Corrosion Protection of Printed Circuit Board Electronics using Cold Atmospheric Plasma-Assisted SiOx Coatings.

The miniaturization and widespread deployment of electronic devices across diverse environments have heightened their vulnerability to corrosion, particularly affecting copper traces within printed circuit boards (PCBs). Conventional protective methods, such as conformal coatings, face challenges including the necessity for a critical thickness to ensure effective barrier properties and the requirement for multiple steps of drying and curing to eliminate solvent entrapment within polymer coatings. This study investigates cold atmospheric plasma (CAP) as an innovative technique for directly depositing ultrathin silicon oxide (SiOx) coatings onto copper surfaces to enhance corrosion protection in PCBs. A systematic investigation was undertaken to examine how the scanning speed of the CAP deposition head impacts the film quality and corrosion resistance. The research aims to determine the optimal scanning speed of the CAP deposition head that achieves complete surface coverage while promoting effective cross-linking and minimizing unreacted precursor entrapment, resulting in superior electrical barrier and mechanical properties. The CAP coating process demonstrated the capability of depositing SiOx onto copper surfaces at various thicknesses ranging from 70 to 1110 nm through a single deposition process by simply adjusting the scanning speed of the plasma head (5-75 mm/s). Evaluation of material corrosion barrier characteristics revealed that scanning speeds of 45 mm/s of the plasma deposition head provided an effective coating thickness of 140 nm, exhibiting superior corrosion resistance (30-fold) compared to that of uncoated copper. As a proof of concept, the efficacy of CAP-deposited SiOx coatings was demonstrated by protecting an LED circuit in saltwater and by coating printed circuits for potential agricultural sensor applications. These CAP-deposited coatings offer performance comparable to or superior to traditional conformal polymeric coatings. This research presents CAP-deposited SiOx coatings as a promising approach for effective and scalable corrosion protection in miniaturized electronics.

Natural deep eutectic solvent-functionalized mesoporous graphitic carbon nitride-reinforced electrospun nanofiber: a promising sorbent in miniaturized on-chip thin film micro-solid-phase extraction prior to liquid chromatography-tandem mass spectrometry for measuring NSAIDs in saliva.

To meet the needs of developing efficient extractive materials alongside the evolution of miniaturized sorbent-based sample preparation techniques, a mesoporous structure of g-C3N4 doped with sulfur as a heteroatom was achieved utilizing a bubble template approach while avoiding the severe conditions of other methods. In an effort to increase the number of adsorption sites, the resultant exfoliated structure was then modified with thymol-coumarin NADES as a natural sorbent modifier, followed by introduction into a nylon 6 polymer via an electrospinning process. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis validated S-doped g-C3N4 and composite production. The prepared electrospun fiber nanocomposite, entailing satisfactory processability, was then successfully utilized as a sorbent in on-chip thin film micro-solid-phase extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from saliva samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Utilizing a chip device, a thin film µ-SPE coupled with LC-MS/MS analysis yielded promising outcomes with reduced sample solution and organic solvents while extending lifetime of a thin film sorbent. The DES-modified S-doped g-C3N4 amount in electrospun was optimized, along with adsorption and desorption variables. Under optimal conditions, selected NSAIDs were found to have a linear range of 0.05-100.0 ng mL-1 with an R2 ≥ 0.997. The detection limits were ranged between 0.02 and 0.2 ng mL-1. The intra-day and inter-day precisions obtained were less than 6.0%. Relative recoveries were between 93.3 and 111.4%.

SU-8-meta-phenylenediamine-conjugated thin film for temperature sensing.

Polymers have distinctive optical properties and facile fabrication methods that have been well-established. Therefore, they have immense potential for nanophotonic devices. Here, we demonstrate the temperature-sensing potential of SU8-meta-phenylenediamine (SU8-mPD), produced by epoxy amination of the SU-8 polymer. Its properties were examined through a series of molecular structural techniques and optical methods. Thin layers have demonstrated optical emission and absorption in the visible range around 420 and 520 nm, respectively, alongside a strong thermal responsivity, characterized by the 18 ppm °C-1 expansion coefficient. A photonic chip, comprising a thin 5-10 µm SU8-mPD layer, encased between parallel silver and/or gold thin film mirrors, has been fabricated. When pumped by an external light source, this assembly generates a pronounced fluorescent signal that is superimposed with the Fabry-Pérot (FP) resonant response. The chip undergoes mechanical deformation in response to temperature changes, thereby shifting the FP resonance and encoding temperature information into the fluorescence output spectrum. The time response of the device was estimated to be below 1 s for heating and a few seconds for cooling, opening a new avenue for optical sensing using SU8-based polymers. Thermoresponsive resonant structures, encompassing strong tunable fluorescent properties, can further enrich the functionalities of nanophotonic polymer-based platforms. This article is part of the theme issue 'Celebrating the 15th anniversary of the Royal Society Newton International Fellowship'.

Ultrahigh Stability and Operation Performance in Bi-doped GeTe/Sb2Te3 Superlattices Achieved by Tailoring Bonding and Structural Properties.

Changes in bond types and the reversible switching process between metavalent and covalent bonds are related to the operating mechanism of the phase-change (PC) behavior. Thus, controlling the bonding characteristics is the key to improving the PC memory performance. In this study, we have controlled the bonding characteristics of GeTe/Sb2Te3 superlattices (SLs) via bismuth (Bi) doping. The incorporation of Bi into the GeTe sublayers tailors the metavalent bond. We observed significant improvement in device reliability, set speed, and power consumption induced upon increasing Bi incorporation. The introduction of Bi was found to suppress the change in density between the SET and RESET states, resulting in a significant increase in device reliability. The reduction in Peierls distortion, leading to a more octahedral-like atomic arrangement, intensifies electron-phonon coupling with increased bond polarizability, which are responsible for the fast set speed and low power consumption. This study demonstrates how the structural and thermodynamic changes in phase change materials alter phase change characteristics due to systematic changes of bonding and provides an important methodology for the development of PC devices.

On the importance of crystal structures for organic thin film transistors.

Historically, knowledge of the molecular packing within the crystal structures of organic semiconductors has been instrumental in understanding their solid-state electronic properties. Nowadays, crystal structures are thus becoming increasingly important for enabling engineering properties, understanding polymorphism in bulk and in thin films, exploring dynamics and elucidating phase-transition mechanisms. This review article introduces the most salient and recent results of the field.

Tuning the Transparency Window of SrVO3 Transparent Conducting Oxide.

Correlated transparent conducting oxides (TCOs) have gained great attention, because of their unique combination of transparency and metallic character. SrVO3 (SVO) was identified as a high-performance TCO in the visible range. Few studies have investigated band structure engineering through chemical doping to enhance the optical properties of SVO. Here, we use two different strategies by exploiting the band-filling and width of the bands derived from Vanadium to tune the screened plasma frequency ωp* and the interband transition Ep-d energy, corresponding to the optical transparency window edges. For control of the band-filling strategy, it is found that Titanium doped SVO has a wide transparency window, but such a composition does not maintain the high electrical conductivity required for TCO applications. Concerning the bandwidth strategy, the doping of SrVO3 by Calcium shows that ωp* remains located in the IR range (1.12 eV), while Ep-d is blue-shifted into the UV region (3.43 eV) due to reinforced electronic correlations. By an appropriate choice of dopant, we successfully increased the size of the transparency window by around 11% from 1.94 eV (SVO) to 2.30 eV (Calcium-doped SVO), while retaining high conductivity of around 2.30 × 104 (S·cm-1) and high charge carrier density of 2.93 × 1022 cm-3.

High-Performance AgSbTe2 Thermoelectrics: Advances, Challenges, and Perspectives.

Environmental-friendless and high-performance thermoelectrics play a significant role in exploring sustainable clean energy. Among them, AgSbTe2 thermoelectrics, benefiting from the disorder in the cation sublattice and interface scattering from secondary phases of Ag2Te and Sb2Te3, exhibit low thermal conductivity and a maximum figure-of-merit ZT of 2.6 at 573 K via optimizing electrical properties and addressing phase transition issues. Therefore, AgSbTe2 shows considerable potential as a promising medium-temperature thermoelectric material. Additionally, with the increasing demands for device integration and portability in the information age, the research on flexible and wearable AgSbTe2 thermoelectrics aligns with contemporary development needs, leading to a growing number of research findings. This work provides a detailed and timely review of AgSbTe2-based thermoelectrics from materials to devices. Principles and performance optimization strategies are highlighted for the thermoelectric performance enhancement in AgSbTe2. The current challenges and future research directions of AgSbTe2-based thermoelectrics are pointed out. This review will guide the development of high-performance AgSbTe2-based thermoelectrics for practical applications.

Enhanced Second-Harmonic Generation in Thin-Film Lithium Niobate Circular Bragg Nanocavity.

Second-order nonlinearity gives rise to many distinctive physical phenomena, e.g., second-harmonic generation, which play an important role in fundamental science and various applications. Lithium niobate, one of the most widely used nonlinear crystals, exhibits strong second-order nonlinear effects and electro-optic properties. However, its moderate refractive index and etching sidewall angle limit its capability in confining light into nanoscales, thereby restricting its application in nanophotonics. Here, we exploit nanocavities formed by second-order circular Bragg gratings, which support resonant anapole modes, to achieve a 42 000-fold enhanced second-harmonic generation in thin-film lithium niobate. The nanocavity exhibits a record-high normalized conversion efficiency of 1.21 × 10-2 cm2/GW under the pump intensity of 1.9 MW/cm2. Besides, we also show s- and p-polarization-independent second-harmonic generation in elliptical Bragg nanocavities. This work could inspire the study of nonlinear optics at the nanoscale on thin-film lithium niobate, as well as other novel photonic platforms.

Emulating Low-Power Synaptic Plasticity in a Solution-Processed Oxide-Based Long Retention Memory Transistor with High Learning Accuracy.

The exploration of synaptic plasticity in metal-oxide-based ferroelectric thin-film transistors has been limited. As a perovskite ferroelectric material, LiNbO3 is widely studied; but its potential use as a neuromorphic device, like synaptic transistors, has not been realized. In this study, a solution-processed ferroelectric thin-film transistor (FeTFT) with an alternating layer of LiNbO3 and Li5AlO4 as a gate dielectric has been fabricated. This configuration reduces the depolarization field by leveraging the large ionic polarization of Li+ ions in the Li5AlO4 layer, while the wide bandgap helps mitigate the leakage current. FeTFT exhibits impressive transistor performance, including a saturation mobility of 0.478 cm2V-1 s-1, an on/off ratio of 3.08 × 103, and a low trap-state density of 1.3 × 1013 cm-2. Moreover, the device demonstrates good memory retention, retaining information for nearly 1 day. It successfully emulates synaptic plasticity, specifically short-term plasticity and long-term plasticity. Besides, a 94% training accuracy has been achieved through artificial neural network simulation. Notably, the FeTFT consumes minimal power, with energy consumption of approximately 3.09 nJ per synaptic event, which is remarkably low compared to other reported solution-processed FeTFT devices.

Effect of N2 reactive gas flow rate on the structural, optical and wettability properties of silicon carbon oxynitride thin films.

In the current research, the silicon carbon oxynitride (SiCON) thin film was deposited on the silicon (Si) substrate by radio frequency (RF) reactive magnetron sputtering method. To comprehensively assess the impact of nitrogen flux rate on thin film characteristics, a suite of advanced analytical methods was utilized. The GIXRD analysis confirmed that the SiCON thin film is amorphous in structure. Additionally, Raman spectroscopy detected no graphite nanocrystals within the film. Ellipsometry measurements further showed that the refractive index of the thin films rises with increased nitrogen flux in the reactive gas, indicating a direct correlation between nitrogen concentration during deposition and optical properties. Based on the designs made with McLeod's software, the amount of reflection can be reduced up to 5.7 % at the wavelength of 4 µm and up to 8.5 % in the wavelength range of 3-5 µm for an optimal thickness thin film. The atomic force microscopy (AFM) examination revealed that the surface roughness of the thin films decreases as the nitrogen flux in the reactive gas mixture increases. Additionally, measurements of the water contact angle (WCA) indicated that the SiCON thin films exhibit a hydrophilic state.

Sensing features, on-site detection and bio-imaging application of a tripodal tris(hydroxycoumarin) based probe towards Cu2+/His.

A new tripodal tris(hydroxycoumarin) based Schiff base, HCTN was synthesized and characterized by FT-IR, 1H NMR, 13C NMR and ESI-HRMS. The probe, HCTN exhibits cyan emission in DMSO/HEPES buffer (9:1, v/v) which selectively detects Cu2+ ion via turn-off fluorescence. The quenching of the fluorescence was due to the binding of the probe, HCTN towards paramagnetic Cu2+ ion resulting in chelation enhanced quenching effect (CHEQ). From the spectroscopic results, the limit of detection of Cu2+ ion was obtained as very low as 0.40 × 10-9 M. The complexation of the metal ion, Cu2+ towards the probe HCTN was confirmed by the ESI-HRMS and Job's plot analysis which supports 1:1 binding stochiometric ratio. In order to validate the affinity of Cu2+ ion towards histidine, the HCTN+Cu2+ system was utilized for the detection of histidine via turn-on mode by the metal displacement approach. The detection limit of His was found to be 7.31 × 10-10 M. In addition to the above, the probe was utilized for various detection applications such as paper strips, cotton swabs, logic gates and thin film applications. The probe, HCTN extends its application to the confocal bioimaging to sense the Cu2+ and Histidine intracellularly.

Pt Single Atoms Loaded on Thin-Layer TiO2 Electrodes: Electrochemical and Photocatalytic Features.

Recently, the use of Pt in the form of single atoms (SA) has attracted considerable attention to promote the cathodic hydrogen production reaction from water in electrochemical or photocatalytic settings. First, produce suitable electrodes by Pt SA deposition on Direct current (DC)-sputter deposited titania (TiO2) layers on graphene-these electrodes allow to characterization of the electrochemical properties of Pt single atoms and their investigation in high-resolution HAADF-STEM. For Pt SAs loaded on TiO2, electrochemical H2 evolution shows only a very small overpotential. Concurrent with the onset of H2 evolution, agglomeration of the Pt SAs to clusters or nanoparticles (NPs) occurs. Potential cycling can be used to control SA agglomeration to variable-size NPs. The electrochemical activity of the electrode is directly related to the SA surface density (up to reaching the activity level of a plain Pt sheet). In contrast, for photocatalytic H2 generation already a minimum SA density is sufficient to reach control by photogenerated charge carriers. In electrochemical and photocatalytic approaches a typical TOF of ≈100-150 H2 molecules per second per site can be reached. Overall, the work illustrates a straightforward approach for reliable electrochemical and photoelectrochemical investigations of SAs and discusses the extraction of critical electrochemical factors of Pt SAs on titania electrodes.

Direct Growth of Bi2SeO5 Thin Films for High-k Dielectrics via Atomic Layer Deposition.

This study describes a modified atomic layer deposition (ALD) process for fabricating BiOxSey thin films, targeting their application as high-k dielectrics in semiconductor devices, especially for two-dimensional semiconductors. Using an intermediate-enhanced ALD technique for Bi2Se3 and a plasma-enhanced ALD process for Bi2O3, a method for the sequential deposition of Bi2SeO5 ternary films has been established. The thin film has been deposited on SiO2 and TiN substrates, exhibiting growth rates of 0.17 to 0.16 nm·cycle-1 without an incubation period, thanks to facile nucleation characteristics. The resulting film exhibited high flatness and reached 96% of its theoretical density, forming a uniform nanocrystalline structure. Electrical evaluations using metal-insulator-metal capacitors indicated the dielectric constant (∼17.6) and electrical breakdown strength (2.6 MV·cm-1), demonstrating their potential as a dielectric layer.

Reliable Operation in High-Mobility Indium Oxide Thin Film Transistors.

Transparent oxide semiconductors (TOSs) based thin-film transistors (TFTs) that exhibit higher field effect mobility (µFE) are highly required toward the realization of next-generation displays. Among numerous types of TOS-TFTs, In2O3-based TFTs are the front-running candidate because they exhibit the highest µFE ≈100 cm2 V-1 s-1. However, the device operation of In2O3 TFTs is unreliable; a large voltage shift occurs especially when negative gate bias is applied due to adsorption/desorption of gas molecules. Although passivation of the TFTs is used to overcome such instability, previously proposed passivation materials do not improve the reliability. Here, it is shown that the In2O3 TFTs passivated with Y2O3 and Er2O3 films are highly reliable and do not show threshold voltage shifts when applying gate bias. Positive and negative gate bias is applied to the In2O3 TFTs passivated with various insulating oxides and found that only the In2O3 TFTs passivated with Y2O3 and Er2O3 films do not exhibit threshold voltage shifts. It is observed that only the Y2O3 grew heteroepitaxially on the In2O3 crystal. This is the origin of the high reliability of the In2O3 TFTs passivated with Y2O3 and Er2O3 films. This finding accelerates the development of next-generation displays using high-mobility In2O3 TFTs.

Wimpled thin films via multiple motions of a bubble decorated with surface-active molecules.

HYPOTHESIS: Thin liquid films play a crucial role in various systems and applications. Understanding the mechanisms that regulate their morphology is a scientific challenge with obvious implications for application optimization. Thin liquid films trapped between bubbles and air-liquid interface can show various configurations influenced by their deformation history and system characteristics. EXPERIMENTS: The morphology of thin liquid films formed in the presence of surface-active molecules is here studied with interferometric techniques. Three different systems with varying interfacial properties are investigated to understand their influence on film morphology. Specific deformation histories are applied to the films to generate complex film structures. FINDINGS: We achieve the creation of a rather stable wimple by implementing controlled bubble motions against the air-liquid interface. We provide a criterion for wimple formation based on lubrication theory. The long-term stability of the wimple is also investigated, and more complex multi-wimple structures are experimentally produced building upon the achieved wimple stability.