Nanowerk May 30, 2022 To overcome the limitations of processing costs, power consumption and integration of miniaturizing silicon-based logic devices, studies are being conducted on electronic and logic devices based on very thin two-dimensional semiconductors at an atomic layer level. An international team of researchers (South Korea, Japan) were able to selectively control the electrical properties of semiconductor electronic devices using Cl-doped tin diselenide (Cl-SnSe2). They were able to freely control the characteristics of the N-type and P-type devices by minimizing defects with the semiconductor interface. In other words, a single device could perform the functions of both N-type and […]
Category Archives: Advanced materials
Writing with light on titania: Rewritable UV-sensitive surfaces made from doped TiO2 nanocrystals
Phys.org May 30, 2022 Nanocrystalline TiO2, a semiconductor, darkens when irradiated with ultraviolet (UV) light due to charge separation and reduction of titanium atoms. The color change is not permanent because oxygen in the air re-oxidizes the titanium and causes a return to transparency. To sustain the color change for a longer period researchers at UC Riverside used nitrogen as a dopant and decorated the crystals with a common non-toxic substance diethylene glycol which played a crucial role in the color change. Using light-writing methods they produced patterns or printed text by illuminating the paper or glass substrate through a […]
Long-hypothesized ‘next generation wonder material’ created
Science Daily May 21, 2022 Scientists have long been interested in the construction of new or novel carbon allotropes. The most well-known carbon allotropes are graphite and diamonds, which are created out of sp2 carbon and sp3 carbon, respectively. However, the traditional methods don’t allow for the different types of carbon to be synthesized together in large capacity. Researchers at the University of Colorado used alkyne metathesis as well as thermodynamics and kinetic control to successfully create a material that could rival the conductivity of graphene but with control. Now the team is looking into the details of it, including […]
Researchers demonstrate organic crystals can serve as energy converters for emerging technologies
Phys.org May 20, 2022 While organic crystals were previously thought to be fragile, an international team of researchers (UAE, USA – New York University) has discovered that some organic crystals are mechanically very robust. They demonstrated that the ferroelectric crystals of guanidinium nitrate exert a linear stroke of 51%, the highest value observed when transitioning at 295–305 K on heating and at 265–275 K on cooling. Their maximum force density is higher than electric cylinders, ceramic piezo actuators, and electrostatic actuators, and their work capacity is close to that of thermal actuators. They demonstrated that the material expanded and contracted over half […]
Rigid waterproof coating for paper aims to reduce our dependence on plastic
Science Daily May 13, 2022 Researchers in Japan developed an easy silica–resin coating technique to compensate for paper’s weaknesses, including its lack of water resistance and strength, and proposed its use as an environmentally friendly alternative to plastic. When they dispersed 2 nm anatase TiO2 nanoparticles on the paper’s cellulose fibers it exhibited moderate photocatalytic effects such as methylene blue degradation and antibacterial activity. The porous silica–resin film which has high adsorptive capacity efficiently captured organic pollutants until they decomposed via photocatalytic reactions. As a result, the stable silica–resin–TiO2 composite coating protected paper from the environment for an extended period, […]
Synthesis of two-dimensional holey graphyne
Science Daily May 18, 2022 While it is possible to overcome limitations of graphene by doping or functionalizing there is also much interest in the search for new types of 2D carbon allotropes. Recently researchers found a top-down way to produce graphene oxides by creating many holes in its structure. An international team of researchers (South Korea, USA – University of Puerto Rico) has developed a bottom-up approach for creating “holey-graphyne” (HGY) constructing the topologically 2D carbon material atom by atom. It consists of alternately HYG linked between benzene rings and C≡C bonds, composed of a pattern of six-vertex and […]
Lightweight nanofiber mats could battle bullets, deflect space debris
Nanowerk February 28, 2022 The weak nature of van der Waals interactions limits the CNT mats from achieving greater performance. Researchers at the University of Wisconsin have developed an efficient approach to augment the inter-fiber interactions by introducing aramid nanofiber (ANF) links between CNTs, which forms stronger and reconfigurable interfacial hydrogen bonds and π–π stacking interactions, leading to synergistic performance improvement with failure retardation. In experiments under supersonic impacts, strengthened interactions in CNT mats enhanced their specific energy absorption up to 3.6 MJ/kg which outperformed bulk Kevlar-fiber-based protective materials. By modifying the interfacial interactions in the mats by adding Kevlar […]
Strong, stretchy, self-healing polymers rapidly recover from damage
Phys.org February 28, 2022 Previously researchers in Japan synthesized multiblock copolymers that exhibited excellent elasticity and self-healing by using the two-component copolymerization of non-polar ethylene and polar methoxyaryl-substituted propylenes. Now they have developed a three-component ‘terpolymer’ of ethylene and two different methoxyaryl-functionalized propylenes using a scandium catalyst. The long, soft sections form a highly flexible matrix, within which are hard and crystalline sections that rapidly re-aggregate after the material is cut, thereby self-healing any damage within five minutes to recover 99% of its toughness and 97% of its tensile strength. The material could be stretched to almost 14 times its […]
New material offers remarkable combo of toughness and stretchiness
Science Daily February 21, 2022 Unlike hydrogel ionic liquids don’t evaporate like water, they are electrically and thermally stable and conduct electricity well, raising interesting opportunities for future applications. An international team of researchers (USA – North Carolina State University, University Nebraska, Australia) has developed a simple one step method for making ionogel. They copolymerized monomers of polyacrylic acid in a solution of ionic liquid using ultraviolet light resulting in a copolymer that incorporates both monomers and the ionic liquid itself. The resulting gel has the stretchability of polyacrylic acid, stronger than the polyacrylamide, and better than cartilage in toughness. […]
New plant-derived composite is tough as bone and hard as aluminum
MIT News February 10, 2022 So far researchers have been able to incorporate low fractions of the exceptionally strong carbon nanocrystals (CNCs), as the crystals tend to clump and only weakly bond with polymer molecules. To develop a composite with a high fraction of CNCs researcher at MIT determined the ratio of CNC and polymer that would turn the solution into a gel, with a consistency that could either be fed through the nozzle of a 3-D printer or poured into a mold to be cast. When dried the material shrank, leaving behind a solid composite composed mainly of cellulose […]