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There is a notable shift toward organic functional materials for their advantages in terms of availability, processability and biodegradability. Solid‐state organic emitters, though rare, are fascinating with diverse range of applications. In this work we utilize crystal engineering principles to design Schiff bases 1 and 2, to realize solid state emission and its tuning. The products have been characterized and studied through crystallographic, Hirshfeld, and optical studies. Structural studies validate crystallization of 1 and 2 with a molecule of methanol and water, respectively, and their packing is predominantly aided by solvent assisted hydrogen bonding, while the π‐π stacking interactions are absent. Crystalline solids are emissive: 1 (λmax 474 nm, τ 0.35 ± 0.04 ns) and 2 (481 nm, 1.80 ± 0.07 ns) and aggregation induced emission (AIE) active. Mechano and thermo‐fluorochromic responses of the products are attributed to phase changes triggered by grinding and desolvation, respectively. The nonemissive solutions of 1 and 2 detect presence of Pb(II) /Hg(II) through emission turn‐on, with limit of detection (LOD) values in the range of 0.0017–0.0022 ppb, while picric acid sensing is reported by their AIE luminogen (AIEgen) forms with LOD values of 0.0017 ppb and 0.0034 ppb, respectively. [ABSTRACT FROM AUTHOR]

The preparation of highly efficient photoluminescent rare‐earth based coordination compounds, characterized by photoluminescence quantum yield (PLQY) over 90% and thermal/chemical stability that allows their processing in various media (aqueous solutions, polymeric films, etc.) holds enormous significance in their applicability. Herein, a family of isostructural coordination polymers (CPs) with 6‐methyl‐2‐oxonicotinate (6m2onic) ligand, chemically and structurally characterized as {[M(6m2onic)4Na(H2O)3]·8H2O}n [where M(III) = Eu (1Eu), Tb (2Tb), Gd (3Gd), Y (4Y) and Eu0.5Tb0.5 (5Eu‐Tb)], are reported. Their peculiar crystal structure, based on a hydrogen‐bonded framework of 1D arrays in which octacoordinated metal centers (established by four chelating 6m2onic ligands) and Na centers are sequentially linked, gives rise to an excellent metal–organic system benefitting from not only bright PL emissions in solid state but also enough chemical and thermal stability as to yield PL water‐soluble complexes and photostable thin‐films. In particular, the terbium(III)‐based counterpart highlights for its first‐in‐class PLQY and versatility, which imbues the compound with efficiencies of 97% in bulk state, 35% in aqueous solution, 85% in polymer‐based thin‐films and 15% after its calcination at 250 °C. The experimental photophysical characterization in those media, involving also pH‐responsive behavior, is well supported by a solid theoretical analysis of their intramolecular transfers and electronic transitions. [ABSTRACT FROM AUTHOR]

Abstract The demand for modern electronics and semiconductors has increased throughout the years, which has enabled the innovation and exploration of solution-processed deposition. Solution-based processes have gained a lot of interest due to the low-cost fabrication and the large fabrication areas without the need for high-vacuum equipment. In this study, we utilized the ZnO ink for inkjet printer ink to fabricate a thin film via Electrohydrodynamic printing. Three different ink solutions were prepared for experimentation. The EHD printing technique demonstrated the ink’s compatibility with and without the modifications. The outcomes of the EHD printed materials were comparable with the spin-coated thin films. The EHD-printed films demonstrated better results in comparison to spin-coated films. Ra and Rq of the EHD film measured at 3.651 nm and 4.973 nm, respectively. It improved the absorbance up to two-fold at 360 nm wavelength and electrical conductivity up to 40% compared to the spin-coated films. Furthermore, the optimization of the printing parameters can lead to the improved morphology and thickness of the EHD thin films.

Organic semiconductors still lag behind their inorganic counterparts in terms of mobility due to their lower structural order, in particular in thin films. Here, the highly ordered phase of triclinic rubrene – characterized by high vertical hole mobility – grown from a vacuum‐deposited thin film is used by post‐annealing and implemented into organic photodetectors. Since the triclinic rubrene exhibits a high roughness with a peak‐to‐valley value of 250 nm, which is detrimental to the dark current, strategies to control the crystal growth are developed. These investigations show that a suppression layer of 20 nm C60 is the most promising approach to successfully reduce the surface roughness while maintaining the triclinic phase, proven by grazing‐incidence wide‐angle X‐ray scattering (GIWAXS). With the smoothened active layer, the dark current density is reduced by three orders of magnitude compared to the neat rubrene layer. It is as low as 2.5 × 10−10 A cm−2 at −0.1 V bias, reflected in an overall specific detectivity of 6 × 1011 Jones at zero bias (based on noise measurements) and a high linear dynamic range of 170 dB. This strategy using a suppression layer thus proves successful and is very promising to be applied to other crystalline materials. [ABSTRACT FROM AUTHOR]

Thin film solar cells are gaining popularity as an affordable, efficient, and flexible substitute for traditional silicon solar cells . This success is closely tied to the deposition techniques used to fabricate their layers. This review explores and analyzes the advances in the major deposition techniques for solar cell applications, offering insights into their underlying principles, associated advantages, drawbacks, and suitability for diverse materials and device architectures. The two primary deposition for thin film solar cells are PVD and CVD. In PVC materials are physically ejecting from a target, and depositing it onto a substrate. While, CVD entails the reaction of gases or vapour precursors to creating film on a substrate. The ability to achieve high purity, control over film properties, scalability, and compatibility with flexible substrates are notable advantages. However, challenges such as high costs and complexity can impact the commercial viability of certain techniques. Recent advancements in the technology of thin film deposition for solar cells include the discovery of novel materials with enhanced light absorption and electronic charge transport capabilities, emerging deposition processes such as pulsed laser deposition, and atomic layer deposition scalable and low-cost processes like roll-to-roll processing, and integration with other technologies like perovskite solar cells and tandem devices. Understanding these techniques and staying informed about recent advancements and future directions empowers researchers and engineers to innovate and create improved thin film solar cells, contributing significantly to a more sustainable future through enhanced solar energy harvesting technologies. [ABSTRACT FROM AUTHOR]

The demand for modern electronics and semiconductors has increased throughout the years, which has enabled the innovation and exploration of solution-processed deposition. Solution-based processes have gained a lot of interest due to the low-cost fabrication and the large fabrication areas without the need for high-vacuum equipment. In this study, we utilized the ZnO ink for inkjet printer ink to fabricate a thin film via Electrohydrodynamic printing. Three different ink solutions were prepared for experimentation. The EHD printing technique demonstrated the ink's compatibility with and without the modifications. The outcomes of the EHD printed materials were comparable with the spin-coated thin films. The EHD-printed films demonstrated better results in comparison to spin-coated films. Ra and Rq of the EHD film measured at 3.651 nm and 4.973 nm, respectively. It improved the absorbance up to two-fold at 360 nm wavelength and electrical conductivity up to 40% compared to the spin-coated films. Furthermore, the optimization of the printing parameters can lead to the improved morphology and thickness of the EHD thin films. [ABSTRACT FROM AUTHOR]

In this work, copper oxide (CuO) thin films were prepared using the pulsed laser deposition (PLD) technique. The effect of laser beam energy and pulse number on the structural, morphological, and topographical characteristics was investigated. X-ray diffraction (XRD) results indicate the presence of characteristic peaks for CuO with a crystalline growth orientation at the (111) plane and an increase in crystallite size (D) when the laser power and number of pulses increase. EDX results indicate the presence of distinct energy peaks for the copper and oxygen elements that form CuO, and the weight percentage (wt.%) of Cu increases with increasing laser energy. The atomic force microscope (AFM) results showed the dependence of the roughness on the laser energy used, as the roughness decreased from 31.18 to 20.89 nm when the energy increased from 700 to 820 mJ. It increases with the increase in the number of laser pulses at the same energy (700 mJ). Field emission scanning electron microscopy (FESEM) confirms the presence of sub-spherical nanoparticles, and increasing laser energy and pulses increases nanoparticle size. [ABSTRACT FROM AUTHOR]

Solid oxide cell technologies play a pivotal role in the realm of renewable energy storage, guiding us through the journey toward decarbonization. Understanding how electrocatalytic materials behave under high‐temperature conditions is an absolute necessity to push these technologies forward. Operando spectroscopic investigations, such as near‐ambient pressure X‐ray photoelectron spectroscopy (NAP–XPS), offer insights into the chemical nature of active working electrodes, including the dynamic response of redox states and adsorbate chemistry to changing electrochemical conditions. Mixed ceramic–metallic electrodes exhibit a limited region with electrochemically active triple‐phase‐boundary (TPB) sites, which are located close to the electrolyte/electrode interface. To monitor this specific region spectroscopically, metallic (Ni) and bimetallic (NiCu) network‐like structures are synthesized on a yttria‐stabilized zirconia electrolyte and the electrochemical state and performance are studied by using operando NAP–XPS. In the experiments, the surface oxidation states under different polarizations are revealed, the gas composition dependent Nernst shift is confirmed, electrocatalytic activities are unraveled, and hydrogen evolution is correlated with the applied potential. The findings demonstrate, the effectiveness of thin‐film model cells with spectroscopically accessible TPB regions for probing interfacial states and electrochemical processes. The obtained fundamental knowledge can provide valuable insights for the advancement of renewable energy storage technologies. [ABSTRACT FROM AUTHOR]

Aluminum has demonstrated compelling attributes over decades of research, encompassing affordability, abundance, and a high specific energy density when utilized as a fuel in energetic materials such as nanothermites. However, fully realizing the ignition and combustion performance of Al poses a significant challenge, primarily due to its high ignition point and sintering tendency, the latter being hypothesized to be the rate-limiting step in Al-based nanothermite combustion. Herein, we examine the influence of nano-TiB2 addition on the ignition and combustion properties of CuO/Al by adjusting the Al-TiB2 binary fuel distribution. Magnetron-sputtered CuO/Al-TiB2 multilayers were prepared, and their ignition and combustion characteristics were studied. It was found that all configurations of the CuO/Al-TiB2 system outperform CuO/Al. Notably, 62.5% loading demonstrated the most significant improvement in the ignition delay, with a decrease of ∼100%. Furthermore, each nano-TiB2-loaded CuO/Al thermite exceeded the propagation rate of CuO/Al by a factor of 2. Differential scanning calorimetry, high-speed videography, spectroscopy, and microscopy were instrumental in elucidating the factors contributing to this improvement and understanding the role of TiB2. While low-temperature TiB2 oxidation contributed to shorter ignition delays, the combustion characteristics were found to be highly controlled by a heterogeneous gas condensed-phase reaction rather than the flame temperature and materials' thermal properties. This study demonstrates that the addition of nano-TiB2 to Al-based thermites holds a significant potential in applications where it is necessary to either lower or finely tune the ignition times. From a manufacturing perspective, this integration technique provides a straightforward approach to enhance the ignition and combustion performance of CuO/Al nanothermites. [ABSTRACT FROM AUTHOR]

Solid oxide cell technologies play a pivotal role in the realm of renewable energy storage, guiding us through the journey toward decarbonization. Understanding how electrocatalytic materials behave under high‐temperature conditions is an absolute necessity to push these technologies forward. Operando spectroscopic investigations, such as near‐ambient pressure X‐ray photoelectron spectroscopy (NAP–XPS), offer insights into the chemical nature of active working electrodes, including the dynamic response of redox states and adsorbate chemistry to changing electrochemical conditions. Mixed ceramic–metallic electrodes exhibit a limited region with electrochemically active triple‐phase‐boundary (TPB) sites, which are located close to the electrolyte/electrode interface. To monitor this specific region spectroscopically, metallic (Ni) and bimetallic (NiCu) network‐like structures are synthesized on a yttria‐stabilized zirconia electrolyte and the electrochemical state and performance are studied by using operando NAP–XPS. In the experiments, the surface oxidation states under different polarizations are revealed, the gas composition dependent Nernst shift is confirmed, electrocatalytic activities are unraveled, and hydrogen evolution is correlated with the applied potential. The findings demonstrate, the effectiveness of thin‐film model cells with spectroscopically accessible TPB regions for probing interfacial states and electrochemical processes. The obtained fundamental knowledge can provide valuable insights for the advancement of renewable energy storage technologies.

Ferroelectric (piezoelectric) lead-free K 0.1 Na 0.9 Nb 0.97 Sb 0.03 O 3 (KNNS) thin films were grown on (111) Pt/Ti/SiO 2 /Si substrates, using radio frequency sputtering. The aim of this work is to determine both the ferroelastic and piezoelectric behaviors associated with the redirection of domains in the lead-free piezoelectric KNNS material. The d 33 piezoelectric coefficient was measured using Piezoresponse Force Microscopy (PFM). The value of the piezoelectric parameter (d 33 = 73 pm/V) observed for KNNS films is more than 25% higher than d 33 values for other lead-free piezoelectric materials reported in the literature. The value of the yield point for the tetragonal KNNS films is Y = 3,83 ± 0.5 GPa. The Elastic modulus is E f = 122 GPa, and the hardness is H f = 8.95 GPa. The scratch hardness of the KNNS thin films is H scr = 5.45 ± 0.2 GPa. Resistance to abrasion is less affected by surface morphological changes than by the indentation measurements. [ABSTRACT FROM AUTHOR]

Hafnium zirconium oxide (HZO) is an ideal candidate for the implementation of ferroelectric memristive devices, due to its compatibility with the complementary metal‐oxide‐semiconductor technology. Ferroelectricity in HZO films is significantly influenced by the properties of electrode/HZO interfaces. Here, the impact of the interfacial microstructure and chemistry on the ferroelectricity of 6 nm‐thick HZO‐based capacitors, realized by sputtering, with titanium nitride or tungsten electrode materials, is investigated. The results highlight a strong correlation between the structural properties of electrode/HZO interfaces and the HZO ferroelectric performance. Interface effects become significant at low HZO thickness, thus the precise control over the quality of electrode/HZO interfaces allows the remarkable improvement of HZO ferroelectric properties. A double remanent polarization of 40 µC cm−2 is achieved. This work is a new step towards high quality ultra‐thin HZO films with enhanced ferroelectricity for the implementation of ferroelectric tunnel junctions for brain‐inspired computing. [ABSTRACT FROM AUTHOR]

Despite enormous progress in the field of surface plasmon resonance (SPR) imaging sensor technology in the past three decades, noble metals like Au and Ag, despite their drawbacks, continue to be the metals of choice for plasmonic sensing layers. The conventional architecture of the SPR sensor based on gold/silver and glass prism hinders scaling, portability, and industrial manufacturing. In this contribution, we present a novel architecture of SPR sensor using copper on polycarbonate prism as a cost-effective, scalable, and mass-producible alternative. Various optimization techniques, such as interface layer, protective encapsulation, and 2D affinity layer are explored to address the challenges related to the practical application of copper in a plasmonic sensor. Our results show that optimized architectures of SPR sensor based on copper has a sensitivity of 235.01°/RIU. From a quantitative analysis of the interrelationships among various performance parameters, we have derived a comprehensive sensing parameter that integrates signal quality and sensitivity. The proposed architecture of the copper based SPR sensor can lead to inexpensive, compact, and handy probes that do not sacrifice accuracy or reliability.

Abstract Hafnium zirconium oxide (HZO) is an ideal candidate for the implementation of ferroelectric memristive devices, due to its compatibility with the complementary metal‐oxide‐semiconductor technology. Ferroelectricity in HZO films is significantly influenced by the properties of electrode/HZO interfaces. Here, the impact of the interfacial microstructure and chemistry on the ferroelectricity of 6 nm‐thick HZO‐based capacitors, realized by sputtering, with titanium nitride or tungsten electrode materials, is investigated. The results highlight a strong correlation between the structural properties of electrode/HZO interfaces and the HZO ferroelectric performance. Interface effects become significant at low HZO thickness, thus the precise control over the quality of electrode/HZO interfaces allows the remarkable improvement of HZO ferroelectric properties. A double remanent polarization of 40 µC cm−2 is achieved. This work is a new step towards high quality ultra‐thin HZO films with enhanced ferroelectricity for the implementation of ferroelectric tunnel junctions for brain‐inspired computing.

The continuously increasing interest in flexible and integrated photonics requires new strategies for device manufacturing on arbitrary complex surfaces and with smallest possible size, respectively. Terahertz (THz) technology can particularly benefit from this achievement to make compact systems for emission, detection and on-demand manipulation of THz radiation. Here, we present a novel fabrication method to realize conformable terahertz metasurfaces. The flexible and versatile character of polymeric nanomembranes is combined with direct laser writing via two-photon polymerization to develop free-standing ultra-thin quasi-perfect plasmonic absorbers with an unprecedentedly high level of conformability. Moreover, revealing new flexible dielectric materials presenting low absorption and permittivity in the THz range, this work paves the way for the realization of ultra-thin, conformable hybrid or all-dielectric devices to enhance and enlarge the application of THz technologies, and flexible photonics in general.

Erbium-doped silica films were synthesized using a two-step sol–gel methodology that involved acid and base catalysts, with erbium concentration ranging from 0.2% to 6% and annealing temperatures varying from 500 °C to 900 °C. The photoluminescence spectra showed that the samples exhibiting efficient emission were annealed at 800 °C and 900 °C and doped with 3% and 6% erbium. The X-ray diffraction analysis revealed that the internal structure of the films was influenced by the different annealing temperatures and the doping concentrations. Samples with dominant 4f transitions were modelled. The results suggest that the proposed method is a promising approach for the synthesis of erbium-doped silica films with potential applications in optical devices. [ABSTRACT FROM AUTHOR]

The effect of nitrogen (N2) partial pressure on the structure and bandgap tunability of RF magnetron sputtered Cadmium Sulphide (CdS) thin films is investigated by varying N2 partial pressure in Ar/N2 mixture. In presence of N2, films have a polycrystalline structure with (002) preferential orientation, which leads to defect-free, continuous, dense, and fibrous structures with increased roughness. The average optical transmittance increased to > 80 at 500–2500 nm for 30 % N2 partial pressure, whereas the band gap decreases from 2.45 eV to 2.30 eV with increasing N2 concentration. This work shows that the bandgap of sputtered CdS thin films can be tuned with the variation of N2 concentration for customized applications.

Carbon black nanocomposites are complex systems that show potential for engineering applications. Understanding the influence of preparation methods on the engineering properties of these materials is critical for widespread deployment. In this study, the fidelity of a stochastic fractal aggregate placement algorithm is explored. A high-speed spin-coater is deployed for the creation of nanocomposite thin films of varying dispersion characteristics, which are imaged via light microscopy. Statistical analysis is performed and compared to 2D image statistics of stochastically generated RVEs with comparable volumetric properties. Correlations between simulation variables and image statistics are examined. Future and current works are discussed. [ABSTRACT FROM AUTHOR]

Due to their high optical efficiency, low-cost fabrication and wide variety in composition and bandgap, halide perovskites are recognized nowadays as real contenders for the development of the next generation of optoelectronic devices, which, among others, often require high quality over large areas which is readily attainable by vacuum deposition. Here, we report the amplified spontaneous emission (ASE) properties of two CsPbBr3 films obtained by single-step RF-magnetron sputtering from a target containing precursors with variable compositions. Both the samples show ASE over a broad range of temperatures from 10 K up to 270 K. The ASE threshold results strongly temperature dependent, with the best performance occurring at about 50 K (down to 100 µJ/cm2), whereas at higher temperatures, there is evidence of thermally induced optical quenching. The observed temperature dependence is consistent with exciton detrapping up to about 50 K. At higher temperatures, progressive free exciton dissociation favors higher carrier mobility and increases trapping at defect states with consequent emission reduction and increased thresholds. The reported results open the way for effective large-area, high quality, organic solution-free deposited perovskite thin films for optoelectronic applications, with a remarkable capability to finely tune their physical properties. [ABSTRACT FROM AUTHOR]

• GaN thin films were deposited using the Thermal Evaporation method. • GaN/Si heterojunction diodes irradiated with different doses of γ-rays. • The electrical and optical properties of GaN/Si heterojunction diodes were studied. This study investigates the impact of γ-irradiation on the material and device properties of Al/n-GaN/p-Si/Al heterojunction diodes. GaN thin films were deposited on glass and p-Si substrates using thermal evaporation, followed by annealing at 450 °C. The diodes were subjected to γ-irradiation doses of 0, 3, and 6 kGy. X-ray diffraction (XRD) measurements revealed significant structural changes, including phase transitions influenced by radiation. Electrical characteristics were assessed through current–voltage (I-V) measurements within the ± 2 V range. Notably, the ideality factor for the annealed diodes improved from 6.60 to 4.62 and 3.85 with increased γ-irradiation. The barrier height was determined to be 0.85 eV, and it did not exhibit a significant change upon γ-irradiation dose. The results provided valuable insights into the response of heterojunction diodes to radiation exposure, aiding in the understanding and potential improvement of the radiation resistance of GaN-based electronic devices. [ABSTRACT FROM AUTHOR]

Crystal engineering is critical for improving the crystal quality and tuning the optoelectronic properties of metal-organic frameworks (MOFs) materials. Doping MOFs is one of the practical approaches to improve the optoelectronic properties of MOFs. Here, a simple and effective method is used to grow MOF nanoparticles as films on the surface of the material. MOF-5 and ZIF-8 nanoparticles can be uniformly grown as films on the Si substrates. The crystalline quality of MOF films is improved after doping with Tb. Meanwhile, two-dimensional conducting photodetectors and photodetector arrays were prepared with perovskite films. Meanwhile, planar conducting photodetector arrays were prepared with MOF films. The photoluminescence (PL) intensity of the Tb-ZIF-8 and Tb-MOF-5 films shows an improvement compared to both ZIF-8 and MOF-5 layers, which leads to improved charge carriers transfer. The maximum photocurrents were about 4 × 10−8 A and 3 × 10−8 A of exposed light at 525 and 425 nm, respectively, at a fixed bias of 10 V for Tb-ZIF-8. The highest photo response of approximately 2.4 × 10−7 and 1.2 × 10−7 A was measured under 525 and 450 nm for the Tb-MOF-5-based device, respectively. The photocurrent behavior is optimized in the visible range due to the increased number of photo-generated carriers at 525 nm. The Tb-MOF-5 based device is a more powerful photodetector than the Tb-ZIF-8 based device under the same conditions. In addition, the stability of Tb-MOF-5 and Tb-ZIF-8 based photodetectors was obtained 77 % and 30 %, respectively. The photodetectors of Tb-MOF-5 have higher stability and better performance than Tb-ZIF-8. [Display omitted] • Fabrication of MOF-5 and ZIF-8 film on uniformly grown as films on the Si substrates. • Improvement of MOF-5 and ZIF-8 films by doping of Tb for crystalline quality as photodetectors. • Tb-ZIF-8 and Tb-MOF-5 films indicate maximum of photocurrents at light at 525 and 425 nm, respectively. • The stability of Tb-MOF-5 and Tb-ZIF-8 photodetectors was obtained 77 % and 30 %, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • A successful methodology to produce large 2D α-MoO 3 nanoplatelets with the [0 1 0] crystallographic direction parallel to the normal of the film surface, and with their crystallographic directions [1 0 0] and [0 0 1] randomly distributed in-plane has been developed. • The synthetized α-MoO 3 nanoplatelets show no overlapping in-plane, and collectively form a dense network that optically behave as an anisotropic film both in the visible and medium infrared. • The anisotropic dielectric function of the nanoplatelet α-MoO 3 films as determined by spectroscopic ellipsometry analysis is reported. • These innovative nanoplatelet α-MoO 3 films behave as a 2D functional nanostructures suitable for the development of multilayer optoelectronic devices. The successful development of nanoplatelet α-MoO 3 −films with wavelength-dependent in-plane and out-of-plane birefringence both in the visible and in the medium infrared is demonstrated. The films are prepared by a two-step process starting from structurally amorphous and continuous substoichiometric MoO 3-X followed by isothermal annealing at low temperature (250 °C) to yield the formation of a dense network of large α-MoO 3 2D nanoplatelets lying in-plane with no overlapping. These α-MoO 3 crystals form a film with excellent thickness uniformity (20 nm) and are oriented with the [0 1 0] crystallographic direction parallel to the substrate normal. Finally, we report the film anisotropic optical complex refractive index, both parallel and perpendicular to the plane the full spectral range from 0.7 to 5 eV as determined by spectroscopic ellipsometry, and their characteristic in-plane phonon mode in the IR from FTIR measurements. These results show a promising pathway to the creation of highly functional anisotropic α-MoO 3 2D films suitable for the development of integrated nanostructured photonic components. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Si-on-W interface between the two thin-films was measured by LEIS, XRR, and TEM. • Comparison of the characterization techniques is made possible by a standard quantification approach. • The sensitivity of LEIS and XRR measurements of thin-film interfaces is investigated. • The sub-atomic effect of the thickness of the W film on the Si-on-W interface is quantified. • A structure with 20 nm W has a sharper Si-on-W interface than a structure with 4 nm W. W/Si thin-film multilayer structures are used in various applications such as X-ray, neutron, and extreme ultraviolet optics. The interfaces between the films play such a fundamental role in the performance of these structures that a sub-nanometer and non-destructive characterization of such interfaces is necessary, albeit challenging. In this study, we investigate the interface Si-on-W and the effect of W thickness on such an interface using low energy ion scattering (LEIS), X-ray reflectivity (XRR), and transmission electron microscopy (TEM). We extract the Si-to-W error-function-like compositional change to quantitatively compare the effective interface width measured by the different techniques. We demonstrate that, in the case of Si-on-W, the effective interface width measured by LEIS and XRR agrees with the values extracted from TEM analysis within a 0.1 nm error margin. Noting that TEM is a destructive method, these results exemplify the value of LEIS and XRR as analysis techniques for resolving thin film interfaces. Surprisingly, all techniques employed in the study show that a structure with 20 nm of W has a sharper Si-on-W interface compared to a structure with 4 nm of W, which we interpret as the effect of both the correlated roughness from the substrate − present in the case of 4 nm W − and the larger crystals − present in the W film in the case of 20 nm W- resulting in less intermixing. This directly shows the value of extracting exact interface widths for the analysis and understanding of thin film growth in multilayer systems. [ABSTRACT FROM AUTHOR]

In this study, we innovatively combine direct ink writing (DIW) and physical vapor deposition (PVD) to fabricate a novel micro igniter with fast-response and low-energy input characteristics. The igniter comprises a 5×5 mm² metal film bridge with gold contact pads. The metallic resistance is fabricated using a series of photolithography, metal deposition, and lift-off processes. After evaluating titanium and chromium as the resistive filament, titanium was selected due to its superior reactivity when in contact with CuO leading to reduced ignition energy. Onto the resistive titanium layer, either thermite multilayer films and/or energetic inks are deposited to achieve a head-to-head comparison of ignition characteristics. We show that igniters powered by (CuO/Ti) 5 bilayers and Al/CuO/PVDF as energetic ink demonstrate the equivalent ignition performance as reactive (CuO/Ti) 5 multilayered igniter. The ignition delay and ignition energy are below 1 ms and 2 mJ, respectively, while the flash intensity is approximately one decade higher than what is typically achieved with conventional micro-igniters. Furthermore, its ignition behaviour can be readily adjusted by altering the constituents of the fuel/oxidizer or adjusting the ratio of multilayer/inks, thereby allowing for easy adaptation of the micro-igniter to meet the diverse requirements of various applications. [Display omitted] • Innovatively combine ink writing and magnetron sputtering to fabricate a fast-response and low-energy input micro igniter. • In detailed elaboration why titanium is a better material for resistive filament in igniters. • Igniters powered by 5 CuO/Ti bilayers and Al/CuO/PVDF as energetic ink feature an ignition delay below 1 ms. • High tunability of ignition behavior by altering constituents of the fuel/oxidizer or adjusting multilayer/inks ratio. [ABSTRACT FROM AUTHOR]

The influence of deposition temperatures on the structural, elemental, optical and electrical properties was investigated. The Rutherford backscattering (RBS) and scanning electron microscopy (SEM) were used to measure the elemental and morphological properties of the films. The RBS confirms that the stoichiometry was controlled by the deposition temperatures with a thickness that ranged between 51.00 to 63.00 nm. SEM data of the deposited films show different morphologies with several grains that increased with deposition temperature. Optical characterization shows that the films exhibited a direct transition with an energy gap that varies from 1.79 to 2.10 eV. For copper-zinc sulphides (CZS) film deposited at 470 C, the maximum electrical conductivity was 7.38 x 10-2 (Ω.cm)-1and minimum electrical resistivity was 1.35 x 101 (Ω.cm). The results confirm the possibility of using copper and zinc dithiocarbamate precursors in depositing high-quality CZS thin films with comparable properties. [ABSTRACT FROM AUTHOR]

Zero-biased photodetectors have desirable characteristics for potentially next-generation devices, including high efficiency, rapid response, and low power operation. In particular, the detector efficiency can be improved simply by changing the electrode contact geometry or morphological structure of materials, which give unique properties such as energy band bending, photo absorbance and electric field distribution. In addition, several combinations of materials enable or disable the operation of selective wavelengths of light detection. Herein, such recent progresses in photodetector operating at zero-bias voltage are reviewed. Considering the advantages and promises of these low-power photodetectors, this review introduces various zero-bias implementations and reviews the key points. [ABSTRACT FROM AUTHOR]

High relative contact electrical resistance and poor flexibility in inorganic thin‐film thermoelectric devices significantly limit their practical applications. To overcome this challenge, a one‐step thermal diffusion method to fabricate assembly‐free inorganic thin‐film thermoelectric devices is developed, where the in situ grown electrode delivers an excellent leg‐electrode contact, leading to high output power and flexibility in the prepared p‐type Sb2Te3/n‐type Bi2Te3 thin‐film device, which is composed of 8 pairs of p‐n junctions. Such a device shows a very low relative contact electrical resistance of 7.5% and a high power density of 1.42 mW cm–2 under a temperature difference of 60 K. Less than 10% change of the whole electrical resistance before and after bending test indicates the robust bending resistance and stability of the device. This study indicates that the novel assembly‐free one‐step thermal diffusion method can effectively enhance the leg‐electrode contact, the device thermoelectric performance, bending resistance, and stability, which can inspire the development of thin‐film thermoelectric devices. [ABSTRACT FROM AUTHOR]

Among cathode materials, LiNi0.8Mn0.1Co0.1O2 (NMC811) is the most discussed for high performance Li‐ion batteries, thanks to its capacity of ≈200 mAh g‐1 and low Co content. Here, it is demonstrated that NMC811 can reversibly accommodate more than one Li‐ion per formula unit when coupled with a solid‐state electrolyte, thus significantly increasing its capacity. Sputtered Li‐rich NMC811 cathodes are tested with lithium–phosphorus–oxynitride as a solid‐state electrolyte in a thin‐film architecture, which is a simplified 2D model with direct access to the cathode‐electrolyte interface. The solid‐state electrolyte helps to stabilize the interface and prevents capacity fading, voltage decay, and interface resistance growth, thus allowing cycling at extended voltage ranges of 1.5–4.7 V. While the liquid electrolyte cells suffer from rapid capacity decay, the Li‐rich NMC811 cells with the solid‐state electrolyte can cycle at a fast rate and an initial capacity of 149 mAh g‐1 from 1.5 to 4.3 V for 1000 cycles. The all‐solid‐state thin‐film cells with a lithium metal anode yield a discharge capacity of up to 350 mAh g‐1 at C/10 because of multi‐electron cycling with a coulombic efficiency of 90.1%. The results demonstrate how solid‐state electrolytes that are stable against NMC811 cathodes can unlock the full potential of this Li‐rich and Ni‐rich cathode class. [ABSTRACT FROM AUTHOR]

The preparation of porous and non-porous chitosan thin-films containing gold nanoparticles was carried out, aiming to evaluate the effect of porosity on their catalytic response using the p-nitrophenol reduction as model reaction. To achieve this, both types of samples were decorated with gold nanoparticles having similar characteristics in terms of amount, size and shape, which were synthesized following a two-step adsorption-reduction process. The results demonstrated that the presence of porosity generates a considerable enhancement of the catalytic property. This behavior is reflected in higher kinetic constant and conversion values, along with a better recyclability after consecutive cycles. The inclusion of porosity in nanocomposites afforded k obs values 7.5 times higher than the non-porous material, as well as conversion values as high as 80 % in <20 min. On the other hand, as an additional experiment, a porous sample prepared with half the amount of gold also exhibited a better performance than the non-porous catalyst, revealing that the porosity allowed to decrease the amount of catalytic metal used and still exhibiting k obs values 5.9 times higher than the non-porous specimen. These studies demonstrate that there is an important synergistic support-nanostructure relationship, which strongly influences the performance of the nanomaterial. [ABSTRACT FROM AUTHOR]

Renewable energy sources, in particular, photovoltaic solar cells and hydrogen fuel, are expected to be the pillars of a sustainable society. Chalcopyrite CuGaSe2 (CGSe) has potential for using in such applications. This article presents efficient solar cells suitable as top cells for tandem devices and highly active photocathodes for solar hydrogen evolution using CGSe photoabsorber layers with modified p–n heterointerfaces. Rb‐doping during the last stage of CGSe film growth effectively improves the photovoltaic performance, and solar cell efficiency of >10% with a high fill factor (FF) of 74.6% is obtained. The half‐cell solar‐to‐hydrogen conversion efficiency reaches 8% with the use of a photocathode composed of a CGSe film grown in an identical growth batch. Interface modification with i) a Cu‐deficient layer, ii) alkali‐metal doping, and iii) an n‐type buffer layer formed on the CGSe film surface is found to a be key to control the energy conversion device parameters, such as the FF and open circuit voltage of solar cells and the onset potential of photoelectrochemical cells, due to the suppression of interface recombination. [ABSTRACT FROM AUTHOR]

Aluminum nitride (AlN) has gained wide interest owing to its high values of elastic modulus, band gap, dielectric strength, resistivity, thermal conductivity and acoustic velocities, especially because it retains most of its properties and versatility in the thin-film form. This review focuses on applications where the CMOS integration of AlN MEMS has been effectively demonstrated. First, the fundamental concepts of piezoelectricity on polycrystalline $c$ -axis oriented thin-films are introduced and AlN is compared to other common piezoelectric materials, namely LiNbO3, LiTaO3, quartz, lead zirconate titanate (PZT), ZnO and GaN by thoroughly discussing the material properties, processing and technological implications. After presenting the possible MEMS-CMOS integration strategies, recent demonstrations of AlN-based devices are reviewed, namely energy harvesters, film bulk acoustic resonators (FBAR), contour mode resonators (CMR), gas sensors, imagers, microphones, transducers for chip-scale communication and calorimetric sensors. Finally, other recent applications/integration opportunities are outlined for AlN-based micro-mirrors, flexible sensors and transducers for liquid media and harsh environments. [2022-0006] [ABSTRACT FROM AUTHOR]

Starting from solid-solutions (SS) of AlCoCrFeNix high-entropy alloys (HEAs) that have been produced with high purity constituent elements by vacuum arc remelting (VAR) method varying the nickel molar ratio x from 0.2 to 2.0, we investigated the synthesis of protective thin films of HEAs and high-entropy nitrides (HENs) with the aid of the pulsed laser deposition (PLD) system. The structure of all ten available bulk targets have been examined by means of X-Ray Diffraction (XRD), as well as their elemental composition by means of energy dispersion X-ray spectroscopy (EDS). Three targets with nickel molar composition x = 0.4, 1.2 and 2.0 corresponding to BCC, mixed BCC and FCC, and finally FCC structures were used for thin film depositions using a KrF excimer laser. The depositions were performed in residual low vacuum (10−7 mbar) and under N2 (10−4 mbar) at room temperature (RT~25 °C) on Si and glass substrates. The deposited films' structure was investigated using grazing incidence XRD, their surface morphology, thickness and elemental composition by scanning electron microscopy (SEM), EDS and X-ray photoelectron spectroscopy (XPS), respectively. A homemade four-point probe (4PP) set-up was applied to determine layers electrical resistance. Besides, a Nanoindentation (NI) was employed to test films' mechanical properties. XRD results showed that all deposited films, regardless of the initial structure of targets, were a mixture of FCC and BCC structures. Additionally, the quantitative and qualitative EDS and XPS results showed that the elemental composition of films was rather close to that of the targets. The depositions under an N2 atmosphere resulted in the inclusion of several percentage nitrogen atoms in a metallic nitride type compound into films, which may explain their higher electrical resistivity. The Young's modulus, nanohardness and friction coefficient values showed that the deposited films present good mechanical properties and could be used as protective coatings to prevent damage in harsh environments. [ABSTRACT FROM AUTHOR]

High performance solution processable n‐type organic semiconductor is an essential element to realize low‐cost, all organic and flexible composite logic circuits. In the design of n‐type semiconducting materials, tuning the LUMO level of compounds is a key point. As a strong electron withdrawing unit, the introduction of chlorine atom into the chemical structure can increase the electron affinity of the material and reduce the LUMO energy level. Here, a series chlorine substituted N‐heteroacene analogues of 6,7,8,9‐tetrachloro‐4,11‐bis(4‐((2‐ethylhexyl)oxy)phenyl)‐[1,2,5]thiadiazolo[3,4‐b]phenazine (O4Cl), 6,7,8,9‐tetrachloro‐4,11‐bis(4‐((2‐ethylhexyl)thio)phenyl)‐[1,2,5]thiadiazolo[3,4‐b]phenazine (S4Cl), 1,2,3,4,8,9,10,11‐octachloro‐6,13‐bis(4‐((2‐ethylhexyl)oxy)phenyl)quinoxalino[2,3‐b]phenazine (8Cl) and 12Cl have been synthesized and characterized. Solution‐processed organic field‐effect transistors (OFETs) based on these four compounds exhibit good electron mobilities of 0.04 cm2 V−1 s−1, 0.01 cm2 V−1 s−1, 2×10−3 cm2 V−1 s−1 and 3×10−3 cm2 V−1 s−1, respectively, under ambient conditions. The results suggest that these chlorine substituted π‐conjugated N‐heteroacene analogues are promising n‐type semiconductors in OFET applications. [ABSTRACT FROM AUTHOR]

The occurrence of oxygen‐driven metal–insulator‐transition (MIT) in SrNbO3 (SNO) thin films epitaxially grown on (110)‐oriented DyScO3 has been reported. SNO films are fabricated by the pulsed laser deposition technique at different partial O2 pressure to vary the oxygen content and their structural, optical, and transport properties are probed. SNO unit cell has been found to shrink vertically as the oxygen content increases but keeping the epitaxial matching with the substrate. The results of Fourier‐transform infra‐red spectroscopy show that highly oxygenated SNO samples (i.e., grown at high oxygen pressure) show distinct optical conductivity behavior with respect to oxygen deficient films, hence demonstrating the insulating character of the formers with respect to those fabricated with lower pressure conditions. Tailoring the optical absorption and conductivity of strontium niobate epitaxial films across the MIT will favor novel applications of this material. [ABSTRACT FROM AUTHOR]

[Display omitted] • First comprehensive examination of the reaction mechanism in nanoZr-based thermite compositions. • Predominance of a low-temperature exothermic event in Zr/CuO redox reaction. • Zr undergoes a sequential three-step oxidation process below 475 °C. • Zr/CuO demonstrates a 400-fold reduction in ignition delay compared to Al/CuO. In this report, we examine the intricate details of the mechanism driving Zr/CuO thermite system, shedding new light on the exceptional reactivity of Zr fuel with oxygen. Magnetron-sputtered Zr/CuO reactive multilayers were deposited, and thermo-physical techniques were employed to characterize the progression of the chemical reaction upon heating. Unlike commonly used Al fuel, Zr/CuO exhibited 100% heat release below 500 °C, contrasting with the ∼5% observed for conventional Al/CuO system. This enhanced reactivity at low temperature is attributed to the rapid oxygen consumption behavior of Zr, due to the poor barrier of ZrO x to oxygen diffusion. The oxidizing behavior of Zr was quantitatively analyzed using electron microscopy and spectroscopy. Our observations reveal a three-step process of Zr oxidation facilitated by a rapid reduction of CuO to metallic Cu accompanied by the formation of an intermediate Cu 2 O phase: (i) a preliminary low-temperature mass transport initiating at 275 °C, (ii) partial Zr oxidation forming ZrO 2 and oxygen enriched Zr and finally (iii) complete conversion to zirconia at 450 °C. Finally, Zr/CuO reactive thin-films demonstrated a very high reactivity with an ignition delay time of 0.04 ± 0.016 ms and a burn rate of 3.5 m.s−1, in stark contrast to the same volume of Al/CuO, which failed to ignite and burn altogether. This study not only deepens our comprehension of Zr-based thermite system but also underscores its potential for diverse applications in energetic materials. [ABSTRACT FROM AUTHOR]

Erbium-doped silica films were synthesized using a two-step sol–gel methodology that involved acid and base catalysts, with erbium concentration ranging from 0.2% to 6% and annealing temperatures varying from 500 °C to 900 °C. The photoluminescence spectra showed that the samples exhibiting efficient emission were annealed at 800 °C and 900 °C and doped with 3% and 6% erbium. The X-ray diffraction analysis revealed that the internal structure of the films was influenced by the different annealing temperatures and the doping concentrations. Samples with dominant 4f transitions were modelled. The results suggest that the proposed method is a promising approach for the synthesis of erbium-doped silica films with potential applications in optical devices.

High-frequency (HF) radio-frequency identification (RFIDs) tags can be combined to electrodes coated with semiconducting thin-films to produce low-cost and disposable sensors with wireless capabilities. Mobile phone applications generally use near-field connection (NFC) to read chip digital information, providing discrete information from the device. To obtain a continuous analogic reading, more sophisticated equipment such as spectrum analyzers are needed. In the present article, we describe a method to obtain the frequency response spectrum of RFID tags using synchronous detection via a lock-in amplifier. The tags were coupled to interdigitated electrodes coated with semiconducting metal oxides (SMOs) to produce UV-sensors and with semiconducting polymer polyaniline (Pani) as chemically responsive wireless devices for the proof-of-concept of the developed method. [ABSTRACT FROM AUTHOR]

To meet the global energy demand, rapid growth in fossil fuel consumption has significantly contributed to global warming. Judicious utilization of renewable energy resources could help to combat this global challenge. Here, we present a comparative study on the designs of static and electro-tunable ‘smart’ windows that could help to reduce the energy need of typical air-conditioning systems deployed in buildings and motor vehicles. Our design comprises insulatorâ€"metalâ€"insulator multi-layered thin-films deposited over a silica glass substrate to filter visible and infrared solar radiation selectively. For static windows, we optimize our design to operate in diverse climatic conditions by choosing different combinations and thicknesses of metal and insulator layers. Whereas for electro-tunable windows, we use an electroâ€"optic polymer as the insulator layers to dynamically control portions of transmitted solar radiation over a voltage range of âˆ'12 to +12 V. Through size-dependence analysis, we could safely assume that the performance of smart windows is less likely to degrade during experimental realization. Our designs are lithography-free, large-area compatible, polarization-independent, angle-insensitive, and robust to fabrication imperfections. The analytical results show a near-perfect match with the simulation findings. The theoretically calculated figure of merit indicates that our proposed smart windows can outperform industry-standard commercial windows. [ABSTRACT FROM AUTHOR]

Multiferroics are a unique class of materials where magnetic and ferroelectric orders coexist. The research on multiferroics contributes significantly to the fundamental understanding of the strong correlations between different material degrees of freedom and provides an energy‐efficient route toward the electrical control of magnetism. While multiple ABO3 oxide perovskites are identified as being multiferroic, their magnetoelectric coupling strength is often weak, necessitating the material search in different compounds. Here, the observation of room‐temperature multiferroic orders in multi‐anion SrNbO3−xNx thin films is reported. In these samples, the multi‐anion state enables the room‐temperature ferromagnetic ordering of the Nb d‐electrons. Simultaneously, ferroelectric responses that originate from the structural symmetry breaking associated are found with both the off‐center displacements of Nb and the geometric displacements of Sr, depending on the relative O‐N arrangements within the Nb‐centered octahedra. The findings not only diversify the available multiferroic material pool but also demonstrate a new multiferroism design strategy via multi‐anion engineering. [ABSTRACT FROM AUTHOR]

Carbon black nanocomposites are complex systems that show potential for engineering applications. Understanding the influence of preparation methods on the engineering properties of these materials is critical for widespread deployment. In this study, the fidelity of a stochastic fractal aggregate placement algorithm is explored. A high-speed spin-coater is deployed for the creation of nanocomposite thin films of varying dispersion characteristics, which are imaged via light microscopy. Statistical analysis is performed and compared to 2D image statistics of stochastically generated RVEs with comparable volumetric properties. Correlations between simulation variables and image statistics are examined. Future and current works are discussed.

Due to their high optical efficiency, low-cost fabrication and wide variety in composition and bandgap, halide perovskites are recognized nowadays as real contenders for the development of the next generation of optoelectronic devices, which, among others, often require high quality over large areas which is readily attainable by vacuum deposition. Here, we report the amplified spontaneous emission (ASE) properties of two CsPbBr3 films obtained by single-step RF-magnetron sputtering from a target containing precursors with variable compositions. Both the samples show ASE over a broad range of temperatures from 10 K up to 270 K. The ASE threshold results strongly temperature dependent, with the best performance occurring at about 50 K (down to 100 µJ/cm2), whereas at higher temperatures, there is evidence of thermally induced optical quenching. The observed temperature dependence is consistent with exciton detrapping up to about 50 K. At higher temperatures, progressive free exciton dissociation favors higher carrier mobility and increases trapping at defect states with consequent emission reduction and increased thresholds. The reported results open the way for effective large-area, high quality, organic solution-free deposited perovskite thin films for optoelectronic applications, with a remarkable capability to finely tune their physical properties.

Despite the considerable significance of utilizing ultra-thin film (utf) hydrogels as multipurpose platforms for biomedical applications, there is still an important lack of adequate characterization techniques suitable for such materials. In this Perspective, the use of quartz crystal microbalance with dissipation (QCM-D) coupled with spectral ellipsometry (SE) is presented as a potential tool for the complete characterization of utf-hydrogels due to its nanometric sensitivity and high versatility. Herein, the fundaments for utf-hydrogel characterization are settled down as far as the QCM-D/SE response is explored under a wide range of different in operando wet working conditions measurements such as temperature or liquid media, among others. Therefore, the design of measuring protocols capable to perform is proposed and compiled, for the first time, complete and precise characterization of the cross-link density, thickness variations (swelling ratio determination), stability analyses, and mechanical studies (including the simultaneous generation of stress-strain curves and the evaluation of the viscoelastic; leading to the final determination of the Poisson's ratio) under different in operando conditions. Finally, the future challenges and implications for the general characterization of soft-thin films are discussed., (© 2024 The Authors. Small published by Wiley‐VCH GmbH.)

In this work we will study the dynamics of a thin layer of a viscous fluid which is embedded in the interior of another viscous fluid. The resulting flow can be approximated by means of the solutions of a free boundary problem for the Stokes equation in which one of the unknowns is the shape of a curve which approximates the geometry of the thin layer of fluid. We also derive the equation yielding the thickness of this fluid. This model, that will be termed as the Geometric Free Boundary Problem , will be derived using matched asymptotic expansions. We will prove that the Geometric Free Boundary Problem is well posed and the solutions of the thickness equation are well defined (in particular they do not yield breaking of fluid layers) as long as the solutions of the Geometric Free Boundary Problem exist. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate the preparation, the optical properties, and the stability over time of a colloidal organic-inorganic hybrid perovskite (CH3NH3PbBr3)/random copolymer P(MMA-co-DMAEMA) system. Different ratios of perovskite to copolymer were used to study its effect on stability and properties. The optical properties were investigated by UV-Vis and fluorescence spectroscopy. Dynamic light scattering was used to determine the size, and the size polydispersity of the colloidal hybrid particles; while morphology was investigated by transmission electron microscopy. Photoluminescence decay studies revealed the interaction of the random copolymer with the perovskite. Finally, thin-films were prepared, to investigate the optical properties of the samples in the absence of the solvent. High temporal stability of the optical properties of thin hybrid films was observed under certain conditions. [ABSTRACT FROM AUTHOR]