Fabrication Of Devices Research Articles

Activation of TADF in Photon Upconverting Crystals of Dinuclear Cu(I)-Iodide Complexes by Ligand Engineering.

This work reports that ligand engineering can modulate the triplet harvesting mechanism in iodide-bridged rhombic Cu2I2 complexes. Complex-1, with a smaller Cu-Cu distance, exhibits phosphorescence from 3(M+X)LCT and 3CC states with 66% quantum yield, whereas an increased Cu-Cu distance in complex-2 results in a switch of the emission from phosphorescence to TADF, which occurs via 1/3(M+X)LCT states with 83% quantum yield. The TADF property of complex-2 has been utilized for the fabrication of a pc-LED emitting efficient warm white light. Moreover, the high charge-transfer nature of these complexes leads to the emergence of third-harmonic generation (THG). Interestingly, complex-1 exhibits efficient third-harmonic generation with a χ(3) value of 1.15 × 10-18 m2 V-2 and LIDT value of 14.73 GW/cm2. This work aims to provide a structure-property relationship to achieve effective harvestation of triplet excitons in iodide-bridged rhombic Cu2I2 complexes and their effective utilization in OLED device fabrication and nonlinear photon upconversion processes.

Blue Emission from Metal Halide Perovskites: Strategies and Applications

Luminescent metal halides, as a type of luminescent semiconductor material, offer advantages that fulfill the requirements of emerging light source devices, such as high luminescence efficiency, good thermal stability, and tunable colorful emission. Blue light being one of the three primary colors plays a crucial role in the field of lighting and colorful displays. However, the progress in device performance of blue‐light materials lags behind that of green and red‐light materials. Currently, there have been numerous reports on metal halide perovskite blue‐light materials, but a comprehensive review on the development and performance control of blue‐light metal halides is yet to be found. This paper provides a comprehensive summary of the design strategies and luminescence mechanisms of blue‐light perovskites with various luminescence centers, as well as their application progress in the fields of light‐emitting diodes (LEDs), X‐ray scintillators, information anti‐counterfeiting and encryption. It also explores possible directions for subsequent performance improvement. This work aims to offer valuable insights and recommendations for the future development of blue‐light metal halides, with significant implications for the fabrication of novel blue light devices and advancements in detection technology.

Designing an occlusal appliance digital protocol using an open-source 3D modeling software program: a technical report.

Occlusal splints are a commonly prescribed dental appliance for the management of bruxism or temporomandibular disorders. The use of digital dental technology facilitates the fabrication of this therapeutic device. The improvements in digital technology have helped in designing and producing occlusal splints that show better precision and accuracy as well as ease of manufacturing in terms of time and materials, in addition to the option of a simple and straightforward duplication process. The present technical report describes the digital workflow steps that need to be followed to design an occlusal device in a fully digital protocol. Scans of maxillary and mandibular models were acquired in centric relation, and a virtual 3D occlusal device was designed using a free, open-source 3D modeling software program.

Beyond Conventional Enhancements: Self-Organization of a Buffer Material on Tin Oxide as a Game-Changer for Improving the Performance of Inverted Organic Solar Cells.

Inverted organic solar cells (OSCs) have garnered significant interest due to their remarkable stability. In this study, the efficiency and stability of inverted OSCs are enhanced via the in situ self-organization (SO) of an interfacial modification material Phen-NaDPO onto tin oxide (SnO2). During the device fabrication, Phen-NaDPO is spin-coated with the active materials all together on SnO2. Driven by the interactions with SnO2 and the thermodynamic forces due to its high surface energy and the convection flow, Phen-NaDPO spontaneously migrates to the SnO2 interface, resulting in the formation of an in situ modification layer on SnO2. This self-organization of Phen-NaDPO not only effectively reduces the work function of SnO2, but also enhances the ordered molecular stacking and manipulates the vertical morphology of the active layer, which suppress the surface trap-assisted recombination and minimize the charge extraction. As a result, the SO devices based on PM6:Y6 exhibit significantly improved photovoltaic performance with an enhanced power conversion efficiency of 17.62%. Moreover, the stability of the SO device is also improved. Furthermore, the SO ternary devices based on PM6:D18:L8-BO achieved an impressive PCE of 18.87%, standing as one of the highest values for single-junction inverted organic solar cells to date.

Cobalt Ion-Modified Titanium Oxide Nanorods: A Promising Approach for High-Performance Electrochromic Application

The development of novel cathodic materials with tailored nanostructures is crucial for the advancement of electrochromic devices. In this study, we synthesized cobalt-doped titanium dioxide (Ti-Co) thin films using a facile hydrothermal method to investigate the effects of cobalt doping on their structural, morphological, and electrochromic properties. Comprehensive characterization techniques, including X-ray diffraction and Raman analysis, confirmed the highly crystalline nature of the Ti-Co thin films, with specific Raman bands indicating distinct modifications due to cobalt incorporation. The TiO2 nanorods, optimally doped with cobalt (TC-3), demonstrated enhanced charge transport and mobility, significantly improving the electrochromic performance. Among the various compositions studied, the TC-3 sample exhibited superior lithium-ion accommodation, achieving an optical modulation of 73.6% and a high coloration efficiency of 81.50 cm2/C. It also demonstrated excellent electrochromic stability, maintaining performance for up to 5000 s of coloring/bleaching cycles. These results confirm the beneficial impact of cobalt doping on the structural and functional properties of the host material. Furthermore, the practical effectiveness of the TC-3 thin film was validated through the fabrication of an electrochromic device, which showed efficient coloration and bleaching capabilities. This comprehensive research enhances the understanding and functionality of Ti-Co nanorod architectures, highlighting their promising potential for advanced electrochromic applications.

Nondestructive Direct Patterning of Both Hole Transport and Emissive Layers for Pixelated Quantum-Dot Light-Emitting Diodes.

Considering the increasing demand for high-resolution light-emitting diodes (LEDs), it is important that direct fine patterning technologies for LEDs be developed, especially for quantum-dot LEDs (QLEDs). Traditionally, the patterning of QLEDs relies on resin-based photolithography techniques, requiring multiple steps and causing performance deterioration. Nondestructive direct patterning may provide an easy and stepwise method to achieve fine-pixelated units in QLEDs. In this study, two isomeric tridentate cross-linkers (X8/X9) are presented and can be blended into the hole transport layer (HTL) and the emissive layer (EML) of QLEDs. Because of their photosensitivity, the in situ cross-linking process can be efficiently triggered by ultraviolet irradiation, affording high solvent resistance and nondestructive direct patterning of the layers. Red QLEDs using the cross-linked HTL demonstrate an impressive external quantum efficiency of up to 22.45%. Through lithographic patterning enabled by X9, line patterns of HTL and EML films exhibit widths as narrow as 2 and 4 μm, respectively. Leveraging the patterned HTL and EML, we show the successful fabrication of pixelated QLED devices with an area size of 3 × 3 mm2, alongside the successful production of dual-color pixelated QLED devices. These findings showcase the promising potential of direct patterning facilitated by engineered cross-linkers for the cost-effective fabrication of pixelated QLED displays.

An InGaAs-based Fin-EHBTFET with a heterogate and barrier layer for high performance

This paper proposes a fin electron-hole bilayer tunneling FET with a heterogate and an InAlAs barrier layer (HBF-EHBTFET). The heterogate can suppress off-state leakage caused by point tunneling, while the InAlAs barrier layer prevents source–drain direct tunneling, significantly reducing the off-state current (I off). P-type Gaussian doping can not only solve the problem of the inability to generate a hole layer during device fabrication, but also reduce the turn-on voltage of line-tunneling, ultimately increasing on-state current and reducing average subthreshold swing (SS avg). By optimizing parameters of the heterogate and InAlAs barrier layer, HBF-EHBTFET can obtain I off of 2.37 × 10−16 A μm−1, SS avg of 17.97 mV dec−1, a cutoff frequency (f T) of 13.2 GHz, and a gain bandwidth product (GBW) of 1.58 GHz. Compared with traditional EHBTFET, HBF-EHBTFET exhibits a reduction in I off by four orders of magnitude, a decrease in SS avg by 65.27%, and an increase in f T and GBW by 78.59% and 93.62%, respectively.

Advancing Frontiers: A High-Impact Study on the Synthesis, Characterization, and Superior Device Performance of AlCr2O4/MXene Nanocomposites

Here we present the fabrication of a multilayer resistive memory device (ReRAM) utilizing AlCr2O4/MXene nanocomposite. Comprehensive investigations into the structural and morphological properties of the nanostructures were conducted using various characterization techniques. The fabricated device was tested by measuring I-V characteristics at different current applications which encompasses all previous results. The band gap value for the nanocomposite was reduced to 2.42 eV while that for AlCr2O4 was measured at 3.25 eV via photoluminescence spectrum. Average particle size of the AlCr2O4/MXene nanocomposite was determined to be 25 nm through powder X-ray diffraction analysis. Crystallographic analysis revealed that all crystal peaks conform to the R-3c (167) space group, indicative of a standard hexagonal crystal structure. Energy-dispersive X-ray readings provided further confirmation that all required elements are present in the sample, affirming successful synthesis of the nanocomposite. Notably, the nanocomposite demonstrated exceptional performance as an electrode material in ReRAM, as evidenced by its current-voltage characteristics, making the AlCr2O4/MXene nanocomposite suitable for a wide range of next-generation device applications.

Enhanced Seebeck effect in gated O-shaped Kekulé graphene junctions

The Seebeck effect in graphene with uniform Kekulé lattice distortion has been studied using the tight-binding model combined with the nonequilibrium Green's function method. The numerical results of this work show that the Seebeck coefficient of the O-shaped Kekulé graphene can be enhanced by modulating the gate voltage. At room temperature (T≈300 K), the Seebeck coefficient for the armchair nanoribbon is Sc≈1370μV/K and for the zigzag nanoribbon is Sc≈1260μV/K. At low temperature (T≈128 K), the Seebeck coefficient for the armchair nanoribbon is Sc≈2500μV/K. In addition, the nano-structuration of the O-shaped Kekulé graphene layer induces an anisotropic behavior in the Seebeck effect. Our work provides an idea for the fabrication of efficient and controllable thermoelectric effect devices.

Ultrathin LiF Insertion and Ensued Contact Resistance Reduction in MoS2 Channel Transistors

Molybdenum disulfide (MoS2) is a representative 2D n‐type semiconductor for various electron devices, but its lateral conduction performances are still restricted, which are mainly attributed to the contact resistance (Rc) in field‐effect transistors (FETs). Low‐enough Rc value must be realized toward practical device fabrications. Herein, 2D MoS2 FETs using chemical vapor deposited (CVD) MoS2 channels with and without the ultrathin LiF interlayer are fabricated, to demonstrate the practical benefits of LiF. In addition, LiF is also applied to Al metal which is known to be more Earth abundant than Au, expecting the similar positive effects of the inserted LiF. When 35 CVD‐grown MoS2 channel FETs with Au are characterized on an identical gate dielectric substrate, the higher value of mobility ranging 55–60 cm2 V s−1 is achieved with the inserted LiF than that without LiF (≈20 cm2 V s−1). In the case of another MoS2 FET with exfoliated flake channel and Al contact, its field‐effect mobility with LiF insertion appears to be ≈35 cm2 V s−1, approaching to an almost Rc‐free mobility (42 cm2 V s−1).

Corrosion behavior of an ultrafine-grained Ti6Al4V-5Cu alloy in artificial saliva containing fluoride ions

Ti6Al4V alloy has been widely used in dental applications, such as orthodontic mini-implants. However, it has been reported that fluoride ions could obviously accelerate the corrosion of implant materials and affect their performance. This work aimed to improve the F− erosion resistance of Ti6Al4V alloy through the strategy of both Cu addition and grain refinement. As contrasted with Ti6Al4V alloy, both the coarse- and ultrafine-grained Ti6Al4V-5Cu alloys effectively mitigated the acceleration of the fluoride ions to the anode process, because Cu substituents blocked the continuous damage of FO· doped in the passive film. Furthermore, grain refinement enhanced the protective ability of the passive film, more oxides and less adsorption amount of fluorides presented in the passive film of ultrafine-grained Ti6Al4V-5Cu alloy than those of coarse-grained Ti6Al4V-5Cu alloy. Under the combination of Cu alloying and grain refinement, the ultrafine-grained Ti6Al4V-5Cu alloy is greatly appropriate for the fabrication of orthodontic devices.

Fabrication of superior conductive composite yarn with 3D continuous CNT/WPU structure for high-performance stretchable heater and sensor

Composite yarns based on coating are suitable for broad application fields and massive production due to the flexibility, efficient fabrication, and economic feasibility. However, challenges remain for composite yarns to simultaneously meet the stringent requirements for stretchability, durability, and functionality in practical application. Herein, we report the fabrication of carbon nanotube (CNT)/waterborne polyurethane (WPU) composite yarn (C/WCY) by inducing CNT/WPU composite ink to construct a 3D continuous conductive structure in draw texturing yarn (DTY) through the capillary effect. Consequently, a high loading of 49 wt% CNTs and conductivity of over 2.3 × 103 S/m were achieved, which enabled C/WCY fast thermal response (120 °C within 8 s), long-term durability, superb electrothermal conversion efficiency (hr+c = 1.38 mW/°C), and excellent electrical properties. The stretchable heater and wearable sensors based on C/WCY were further achieved by braiding and weaving technology. This work offered new opportunities for scalable, fast, and low-cost fabrication of wearable electric devices.

Simple chemical solution deposition of Al2O3 dielectric layers for low-cost fabrication of transparent electronic devices

Simple chemical solution deposition of Al2O3 dielectric layers for low-cost fabrication of transparent electronic devices

Impact of doping on the Bridgman grown organic stilbene single crystal for third order NLO applications

Transparent 1, 3, 5-Triphenylbenzene doped Stilbene (TBS) single crystal was successfully grown by employing the Bridgman technique. SCXRD studies found crystallographic parameters, which reveal that the TBS single crystal has crystallized in a monoclinic crystal structure with the space group of P21/C. The identification of the functional groups in the TBS crystal was accomplished through the FTIR analysis. The UV–Vis spectral data shows that the TBS crystal exhibits minimal absorption across the visible spectrum, with a lower cutoff wavelength of 365 nm. The violet emission is observed at 380 and 405 nm in the fluorescence analysis. Additionally, the crystal's high quality was confirmed by a full width at half maximum value of 123 arcsec in the prominent rocking curve peak. Third-order nonlinear optical susceptibility χ(3) was determined to be 4.26 × 10−6 esu using the Z-scan technique. These are exciting findings that highlight the TBS crystal's suitability for various applications, including scintillation and optoelectronic device fabrication.

Electrochemical study and structural comparison of Ni electrodepositions on W/Si and Cr/C multilayered structure films

The Ni electrodeposition combined with multilayered structure film is a promising strategy in modern optical manufacturing, while less effort has been devoted to comprehending the electrochemical reaction process, which is essential for their practical applications. In view of this, the initial reduction dynamics and nucleation mechanisms of Ni electrodepositions on multilayer W/Si and Cr/C films were analyzed in this work, and the morphological, crystal, and mechanical characteristics of produced Ni electrodeposits were further determined and compared. The results show that the considerably irregular crystals accompanied by high tensile stress of 119.5 MPa were formed for the Ni electrodeposit on W/Si film, which were mainly attributed to the progressive nucleation process with more severe side reaction of hydrogen evolution. By contrast, the instantaneous nucleation mode with lower reduction resistance were revealed for the Ni electrodeposition on Cr/C film, which presented a comparatively fine–grained texture, less roughness, and smaller stress structure. To summarize, the more stable electrochemical reaction process and improved structure uniformity are obtained for the Ni electrodeposition on metal/C–based film, which offers a theoretical guidance for optimized fabrication of multilayer optical devices in extreme ultraviolet, x-ray, and neutron focusing fields.

Molten glass-mediated conditional CVD growth of MoS2 monolayers and effect of surface treatment on their optical properties

In the rapidly developing field of optoelectronics, the utilization of transition-metal dichalcogenides with adjustable band gaps holds great promise. MoS2, in particular, has garnered considerable attention owing to its versatility. However, a persistent challenge is to establish a simple, reliable and scalable method for large-scale synthesis of continuous monolayer films. In this study, we report the growth of continuous large-area monolayer MoS2 films using a glass-assisted chemical vapor deposition (CVD) process. High-quality monolayer films were achieved by precisely controlling carrier gas flow and sulfur vaporization with a customized CVD system. Additionally, we explored the impact of chemical treatment using lithium bistrifluoromethylsulfonylamine (Li-TFSI) salt on the optical properties of monolayer MoS2 crystals. To investigate the evolution of excitonic characteristics, we conditionally grew monolayer MoS2 flakes by controlling sulfur evaporation. We reported two scenarios on MoS2 films and flakes based on substrate-related strain and defect density. Our findings revealed that high-quality monolayer MoS2 films exhibited lower treatment efficiency due to substrate-induced surface strain. whereas defective monolayer MoS2 flakes demonstrated a higher treatment sensitivity due to the p-doping effect. The Li-TFSI-induced changes in exciton density were elucidated through photoluminescence, Raman, and x-ray photoelectron spectroscopy results. Furthermore, we demonstrated treatment-related healing in flakes under variable laser excitation power. The advancements highlighted in our study carry significant implications for the scalable fabrication of diverse optoelectronic devices, potentially paving the way for widespread real-world applications.

Large Area Film of Highly Crystalline, Cleavable, and Transferable Semi-Conducting 2D-Imine Covalent Organic Framework on Dielectric Glass Substrate.

Two dimensional (2D) imine-based covalent organic framework (COF), 2D-COF, is a newly emerging molecular 2D polymer with potential applications in thin film electronics, sensing, and catalysis. It is considered an ideal candidate due to its robust 2D nature and precise tunability of the electronic and functional properties. Herein, we report a scalable facile synthesis of 2D imine-COF with control over film thickness (ranging from 100 nm to a few monolayers) and film dimension reaching up to 2 cm on a dielectric (glass) substrate. Highly crystalline 2D imine polymer films are formed by maintaining a quasi-equilibrium (very slow, ∼15 h) in Schiff base condensation reaction between p-phenylenediamine (PDA) and benzene-1,3,5-tricarboxaldehyde (TCA) molecules. Free-standing thin and ultrathin films of imine-COF are obtained using sonication exfoliation of 2D-COF polymer. Insights into the microstructure of thin/ultrathin imine-COF are obtained using scanning and transmission electron microscopy (SEM and TEM) and atomic force microscopy (AFM), which shows high crystallinity and 2D layered structure in both thin and ultrathin films. The chemical nature of the 2D polymer was established using X-ray photoelectron spectroscopy (XPS). Optical band gap measurements also reveal a semiconducting gap. This is further established by electronic structure calculation using density functional theory (DFT), which reveals a semiconductor-like band structure with strong dispersion in bands near conduction and valence band edges. The structural characteristics (layered morphology and microscopic structure) of 2D imine-COF show significant potential for its application in thin film device fabrication. In addition, the electronic structure shows strong dispersion in the frontier bands, making it a potential semiconducting material for charge carrier transportation in electronic devices.

Superb Silk Hydrogels with High Adaptability, Bioactivity, and Versatility Enabled by Photo-Cross-Linking.

The exceptional biocompatibility and adaptability of hydrogels have garnered significant interest in the biomedical field for the fabrication of biomedical devices. However, conventional synthetic hydrogels still exhibit relatively weak and fragile properties. Drawing inspiration from the photosynthesis process, we developed a facile approach to achieve a harmonious combination of superior mechanical properties and efficient preparation of silk fibroin hydrogel through photo-cross-linking technology, accomplished within 60 s. The utilization of riboflavin and H2O2 enabled a sustainable cyclic photo-cross-linking reaction, facilitating the transformation from tyrosine to dityrosine and ultimately contributing to the formation of highly cross-linked hydrogels. These photo-cross-linking hydrogels exhibited excellent elasticity and restorability even after undergoing 1000 cycles of compression. Importantly, our findings presented that hydrogel-encapsulated adipose stem cells possess the ability to stimulate cell proliferation along with stem cell stemness. This was evidenced by the continuous high expression levels of OCT4 and SOX2 over 21 days. Additionally, the utilization of photo-cross-linking hydrogels can be extended to various material molding platforms, including microneedles, microcarriers, and bone screws. Consequently, this study offered a significant approach to fabricating biomedical hydrogels capable of facilitating real-time cell delivery, thereby introducing an innovative avenue for designing silk devices with exceptional machinability and adaptability in biomedical applications.

Conducting Polymers–Metal Chalcogenides Hybrid Composite: Current Trends and Future Prospects Toward Supercapacitor Applications

Conducting polymers have grown in popularity as electrode materials in supercapacitors due to their polymeric mechanical structure and outstanding conductivity. Nanostructured conducting polymers, in particular, have been the focus due to unique properties such as higher surface area, shorter diffusion lengths for ion transport, and a high electrochemical nature. Nonetheless, the volumetric expansion of conducting polymer electrodes after long charge–discharge cycles reduces capacitance retention. Metal chalcogenides, on the other hand, are distinguished from other metallic compounds by their distinctive 2D structure, large theoretical capacities, abundant electrochemical active sites, and tunable shape, enabling them as a potential candidature when combined with conducting polymers to produce a composite material taking “material mutualism” to enhance the properties. Hence, the review focuses on recent advancement in the field of creating conducting polymers–metal chalcogenides composite for supercapacitors. It especially covers how nanoarchitecture, composition, and doping affect the electrochemical characteristics of these composites. A brief introduction of several synthesis procedures is also offered, which includes chemical approaches with and without templates or binder additives. Furthermore, noteworthy works on the fabrication of symmetric and asymmetric devices are highlighted.

Toward Practical Single-Molecule/Atom Switches.

Electronic switches have been considered to be one of the most important components of contemporary electronic circuits for processing and storing digital information. Fabricating functional devices with building blocks of atomic/molecular switches can greatly promote the minimization of the devices and meet the requirement of high integration. This review highlights key developments in the fabrication and application of molecular switching devices. This overview offers valuable insights into the switching mechanisms under various stimuli, emphasizing structural and energy state changes in the core molecules. Beyond the molecular switches, typical individual metal atomic switches are further introduced. A critical discussion of the main challenges for realizing and developing practical molecular/atomic switches is provided. These analyses and summaries will contribute to a comprehensive understanding of the switch mechanisms, providing guidance for the rational design of functional nanoswitch devices toward practical applications.