Materials Today Electronics最新文献

Electrical circuit manufacture for flexible electronics is a very specialized printing process in which electrically functional inks are printed onto a substrate. In almost all cases, the substrate assumes a passive role in ink distribution, which has been the conventional methodology used up until now. Herein we have discovered that a sodium carboxymethyl cellulose (CMCNa) hydrogel substrate demonstrates heightened susceptibility to UV photo-irradiating and because of molecular-level bond lability that leads to a macroscopic improved swelling (“writing” action). The localized photo-activated events lead to temporary 3D contours on the hydrogel substrate where conductive ink is held in valleys to allow the formation of conductive traces. A self-distribution of ink in the valleys is achieved which, moreover, is a type of mask-based photolithography or digital image generation. The process can be employed for polymeric inks such as PEDOT:PSS to obtain ink patterns without need of complex inkjet printers or other conventional printers. The drying causes recession of the temporary swollen hydrogel contours and returns the surface to flattened format. The process works at lower ink solids of 0.125 % and has shown that 1.15 J/mm² of UV energy is capable of creating an electrically isolated conductive pattern. Initial water content of the system plays an important role in which 20 g/g of absorbed water/substrate is sufficient for acceptable pattern generation.

Flexible dielectric barrier discharge (FXDBD) plasma devices have received extensive attention for the surface treatment of larger areas, nonflat surfaces, or curved objects. The rapid development of flexible electronics technology allows unrestricted versatility for designing and manufacturing FXDBD devices. The flexible structure of FXDBD plasma opens new possibilities that cannot be effectively achieved by conventional rigid-body plasma systems, particularly in treating complex surface structures in biological targets. Over the last decade, FXDBD plasma devices have been broadly utilized for surface sterilization, wound solutions, and food processing applications. This review provides a comprehensive overview of current advances in FXDBD plasma, considering important aspects of manufacturing processes and critical application accomplishments. The challenges and perspectives for the future development of FXDBD plasma are also discussed.

Tandem solar cells (TSCs) are poised to revolutionize photovoltaic (PV) technology as they hold the promise of a significantly higher power conversion efficiency (PCE) compared to the current dominant single-junction solar cells. TSCs are composed of two different absorbing materials, strategically utilizing the shared incident solar spectrum to achieve a synergistic boost in PCE. The perovskite/Cu(In,Ga)Se₂ (CIGS) TSCs, as a cutting-edge and prospective solar energy conversion device, have sparked widespread research interest by synergistically combining the unique advantages of perovskite and CIGS materials. This comprehensive review presents a thorough investigation of the latest research advancements in perovskite/CIGS TSCs, with a specific focus on the intricacies of device structure design and state-of-the-art fabrication methods. Significant attention is devoted to elucidating the pivotal role of interface engineering, material composition optimization, and precise control of processing parameters in determining the PV performance of the devices. By optimizing the stacked architecture and enhancing material interfaces, the review demonstrates how substantial improvements have been achieved in terms of high-efficiency PV conversion and superior carrier transport, consequently elevating the performance and long-term device stability. Finally, the review provides a compelling outlook on the future development of perovskite/CIGS TSCs, aiming to drive further advancements and practical applications of this advanced technology.

Ferroelectric materials with electrically switchable spontaneous polarization are technologically important for developing next-generation low-power nanoelectronics and ferroelectronics. Regardless of significant challenges for rich functionalities owing to the insulating nature of conventional thin-film ferroelectrics, ferroelectricity instability or disappearance below a critical thickness limit generally exists. Therefore, exploring emerging two-dimensional (2D) ferroelectric materials with nanoscale dimensions and moderate bandgaps is crucial for developing high-integration functional nanoelectronics. This review offers a comprehensive analysis of the historical background and progression in both thin-film ferroelectrics and novel 2D ferroelectrics. Special attention is given to the device applications based on the emerging 2D ferroelectrics, in which the polarization switching process occurs within the channel material itself. Leveraging the switchable polarization in nanoscale 2D ferroelectrics, rationally designed device configurations with intriguing working mechanisms have been rapidly developed in various application scenarios, such as gate-tunable memristors, non-volatile memories, biological synapses, in-memory computing, etc. This review also sheds light on the potential opportunities and challenges in the future advancement of integrating novel 2D ferroelectric materials into devices within commercial electronic circuits.

Flexible electrochromic (EC) technology has made huge progress in electronic industry for their applications in flexible displays, e-papers, e-curtains etc. The performance of device is the main concern while fabricating a flexible electrochromic device. In this paper, a solid state flexible electrochromic device (flex-ECD) has been demonstrated by combining the excellent EC performance of organic polymer and excellent stability of metal oxides which exhibits fast color switching and excellent stability after bending and twisting it for several times. For the fabrication of device, first Co₃O₄ and WO₃ powders have been synthesised and utilised as dopants in the two electrochromic active materials namely polythiophene (P3HT) and ethyl viologen (EV), respectively. Due to the doping of these nanomaterials the performance of the flex-ECD has been enhanced as measured in terms of coloration efficiency, switching time and stability. Additionally, the device shows color switching in their different wavelength regions between visible and NIR. The flex-ECD shows high stability with a few seconds of switching time and high coloration efficiency of 420 cm²/C. The device was first bent and subsequently twisted for several more times. After bending, the performance has been checked, exhibiting minimal change in switching time at 515 nm and 665 nm without compromising the coloration efficiency much. The device shows excellent stability after bending and twisting moments making it a good design for future wearable electronics.

Magnetic van der Waals (vdW) materials are highly sensitive to their chemical compositions and atomic structures, which presents rich opportunities for synthetic control of vdW ferromagnets. Here, we synthesized the quaternary alloys Cr₂Si_xGe_2-xTe₆ using the flux method and discovered that the Ge:Si source ratio should be designed deliberately higher than the expected in resultant crystals due to the stronger affinity of Si than Ge to be involved in Cr₂Si_xGe_2-xTe₆ reactions. Temperature-dependent magnetization and magnetic hysteresis measurements revealed that as the Si content increases, the Curie temperature decreases while the out-of-plane anisotropy increases monotonically. When x increases from 0 to 2 in Cr₂Si_xGe_2-xTe₆, the out-of-plane saturation fields remain approximately unchanged at ∼0.2 T, while the in-plane saturation fields increase monotonically from 0.5 T to 1.2 T. The distinct behaviors between out-of-plane and in-plane saturation fields arise from the different mechanisms underpinning the two fields – the out-of-plane saturation field is determined by the competition of exchange interaction, magnetic anisotropy, and dipolar interaction, whereas the in-plane saturation field by magnetic anisotropy. Our compositional engineering provides a fundamental understanding of the layered magnetic materials and insightful guidance for the future design of vdW magnets.

The light-emitting efficiencies of blue perovskite light-emitting diodes (PeLEDs) based on quasi-two-dimensional (quasi-2D) halide perovskite emissive layers still lag behind in comparison to their green and red counterparts. The buried interfaces strongly affect the properties of upper solution-processed quasi-2D halide perovskites and the resultant PeLEDs. Herein, it is proposed to passivate the defects of blue quasi-2D perovskites at the buried interfaces by modifying the poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) hole-transport layer (HTL) with 4-guanidinobutyric acid (GBA). The GBA-modified PEDOT:PSS can help to passivate the defects of blue quasi-2D perovskites at the buried interfaces through the interaction between the amine groups of GBA and lead ions and enhance the ratios of halide ions and 4-fluorophenylethylammonium bromide to lead ions. Owing to the reduced halogen vacancies and the passivated defects at the buried interfaces, the blue quasi-2D perovskites prepared on the GBA-modified PEDOT:PSS HTL lead to an increased photoluminescence quantum yield (PLQY) of 60.8 %. The corresponding sky blue PeLEDs achieve a maximum light-emitting quantum efficiency of 9.41 % with an emission peak at 488 nm. This work contributes to enhancing the light-emitting performance of blue PeLEDs through the buried interface passivation point of view.

Pseudocapacitors with oxygen-enriched vacancies have been the state-of-the-art surface chemistry to invoke various intrinsic mechanisms. Nevertheless, the electrochemical behavior of vacancies-induced properties of MoO₃ is still under debate. In this work, we report an oxygen-enriched polymorph of molybdenum trioxide (MoO₃), i.e., H₂MoO₅, which is a thermodynamically unstable phase of MoO₃ with aliovalent oxygen ions (O₂^2- and O₂^-), to achieve a higher amount of pseudocapacitance compared to its thermodynamically stable phase (alpha-MoO₃). Mott-Schottky analysis identified a higher proportion of oxygen vacancies in H₂MoO₅ compared to MoO₃. A symmetric supercapacitor of H₂MoO₅ with PVA/H₂SO₄ displayed a high charge storage of 46.54 F/g at a current density of 0.5 A/g, maintaining a remarkable cycle life of up to 6000 cycles. Furthermore, the oxygen-enriched cell could deliver a high-power density of 470 W/kg at a higher energy density of 22.8472 Wh/kg. The ability to tune oxygen vacancies in metal oxide systems opens a new platform to enhance pseudocapactive character without compromising the energy density.

The emergence of the fascinating non-linear Hall effect intrinsically depends on the non-zero value of the Berry curvature dipole. In this work, we predict that suitable strain engineering in layered van der Waals material phosphorene can give rise to a significantly large Berry curvature dipole. Using symmetry design principles, and a combination of feasible strain and staggered on-site potentials, we show how a substantial Berry curvature dipole may be engineered at the Fermi level. We discover that monolayer phosphorene exhibits the most intense Berry curvature dipole peak near 11.8% strain, which is also a critical point for the topological phase transition in pristine phosphorene. Furthermore, we have shown that the necessary strain value to achieve substantial Berry curvature dipole can be reduced by increasing the number of layers. We have revealed that strain in these van der Waals systems not only alters the magnitude of Berry curvature dipole to a significant value but allows control over its sign. We are hopeful that our predictions will pave way to realize the non-linear Hall effect in such elemental van der Waals systems.

Understanding the charge transport physics is crucial for improving organic field-effect transistors (OFETs) performance. Diverse mobility behaviour has been discovered and numerous theories have been established to explain the nature of charge transport in OFETs. In this review, the theories are divided into three groups, band-like theories, transient localization models, and hopping transport. The relationship between structural properties and intrinsic charge transport physics will be discussed. The fundamental assumptions and theoretical framework of these models will be introduced and their advantages and limits when describing charge transport in OFETs are also discussed based on recent experimental observations. Band-like theory is more applicable to highly-ordered single crystals while hopping models concentrate on disordered materials. Newly developed transient localization theories emphasize the importance of thermal fluctuations, which hopping theories and band-like models fail to include, attributed to weak van der Waals interactions. We integrate and summarize these theories to provide a more sophisticated understanding and more universal descriptions of the charge transport process to guide further developments and potential applications of OFETs.