GIANT最新文献

Polymer dielectrics are widely used in modern power electronics due to their high flexibility and high breakdown strength. However, the limited energy density of current polymer dielectrics limits their wider applications, and there is an urgent need to develop novel polymer dielectric materials. Poly(lactic acid) (PLA) is favored for biological applications due to its biocompatibility and biodegradability. In general, PLA has three optical isomers, namely poly(L-lactide) (PLLA), poly(D-lactide) (PDLA), and poly(DL-lactide) (PDLLA), but the investigation of their dielectric properties remains limited. In this study, a significant increase in energy storage density and charge/discharge efficiency in poly(methyl methacrylate) (PMMA) was achieved by incorporating isomers of PLA into PMMA. Experimental results indicate that the introduction of PLA creates a phase-separated structure within PMMA, and in particular, the introduction of the crystalline region significantly improved the breakdown strength (E_b). Finally, PLLA/PMMA 50/50 and PDLA/PMMA 50/50 exhibit the discharged energy densities of 8.55 J cm⁻³ and 8.18 J cm⁻³, respectively, with charge/discharge efficiencies of 89.6% and 90.9%. This work enables the achievement of all-organic dielectrics with high energy storage density and high efficiency through the construction of phase-separated structures and demonstrates the great potential of biodegradable polymers in electronic devices.

The polymer gels containing dynamic cross-links and mesogenic groups are among the key candidates for the development of soft actuators and detectors, displays, sensors and other programmable and self-healing materials. In this article, firstly, the collapse of polymer networks with irreversible cross-links in the presence of a dynamic cross-linker is investigated by means of Flory-type theory. It is shown that, at not a very poor solvent quality (near the theta-conditions), the swelling ratio for a gel containing irreversible and dynamic cross-links is less than for a gel with irreversible cross-links only, whereas at poor or good solvent qualities sizes of these gels are close to each other. The number of dynamic cross-links monotonically increases with worsening the solvent quality. The gel contraction can be also achieved by increasing the dynamic cross-linker concentration, which allows one to change the transition point in a wide range of solvent conditions. Secondly, polymer networks containing irreversible and dynamic cross-links and incorporating mesogenic side groups is studied using the Maier–Saupe theory. With decreasing in the temperature, the continuous transition from a swollen to collapsed state occurs. With further increase in the temperature, the swelling ratio discontinuously decreases and the nematic order parameter sharply increases from zero to a value ​​close to one. By increasing the dynamic cross-linker concentration, the swelling-to-collapse transition and, then, the isotropic-nematic transition are observed. A phase diagram of the gel is constructed and, depending on the dynamic cross-linker concentration and temperature, the swollen gel with the zero nematic order parameter, the collapsed gel with the zero nematic order parameter, and the collapsed gel with the nematic ordering can be formed. A growth of the length of the mesogenic side group leads to an increase in the area of ​​existence of the collapsed gel with the nematic ordering in the phase diagram. The obtained theoretical results are in agreement with corresponding experimental data from the literature.

Anode modification and optimization is crucial towards improving performance of organic solar cells (OSCs). PEDOT:PSS is the most common choice as a hole transport layer (HTL) material, but suffers from issues including low conductivity. In this work, three alkyl amine derivatives - methylamine hydrochloride (MA), ethylamine hydrochloride (EA) and propylamine hydrochloride (PA) are doped into the commercially available Al 4083 PEDOT:PSS to form PEDOT:PSS-MA, PEDOT:PSS-EA and PEDOT:PSS-PA, as modified HTLs. All these modified HTLs exhibit improved chemical and electrical properties including work functions (WF), conductivities and charge carrier motilities. The alkyl amine doping shows compatibility in both Small Molecular Acceptors and All-Polymer OSCs. With PEDOT:PSS-MA demonstrates a highest PCE of 18.49 % compared to the 17.84 % of OSC devices prepared with pristine PEDOT:PSS with the PM6:L8-BO system, while PM6:PY-IT all-polymer OSCs improve PCE from 14.53 % to 15.22 %. AFM characterizations reveal that the introduction of the dopants have smoothened the surface morphology of spin-coated HTL films, which contributes towards more efficient charge extraction. In summary, this study not only presents a method of improving OSC efficiencies, but also provides insight and further possible directions towards anode optimization of OSCs.

Alternating current electroluminescent (ACEL) devices have attracted tremendous attention due to their significant applications in bioinspired electronics, smart wearables, and human-machine interfaces. However, it still faces limitations in real-time visual temperature sensing. Herein, a universal strategy is established to achieve real-time temperature dynamic visualization by integrating a thermochromic layer through a simple spin coating procedure. Such elaborate integration permits the device to display a wide array of luminous colors and achieve high-contrast color transitions in response to ambient temperature variations. More importantly, a quantitative relationship can be established between the temperatures and the luminous color changes. This advancement not only enhances multi-color emission capabilities but also enables the display of diverse information, marking a significant stride in the development of dynamic temperature sensing in ACEL devices.

Giant molecule acceptors (GMAs) are composed of two or more narrow bandgap small molecule acceptors (SMAs) subunits connected by conjugated or non-conjugated linking units, which possesses the advantages of the SMAs with broad absorption, appropriate electronic energy levels and fixed molecular weight (with good photovoltaic performance reproducibility), and the polymerized SMAs (PSMAs) with good film-forming property and high morphology stability and photo-stability. So that the GMAs are promising for future commercial application in polymer solar cells (PSCs). Therefore, the GMAs have attracted great attention recently. In this review, we will briefly introduce the development of the narrow bandgap SMAs, especially the A-DA’D-A structured SMAs, and the PSMAs. Then we will focus on the recent research progress of the GMAs, including the synthetic method of GMAs and the effect of number of the SMA subunits on the photovoltaic performance of the GMAs. Finally, we present our perspectives and offer a concise outlook on the further advancement of the GMAs.

Lithium metal batteries (LMBs) with high energy density have been deemed as one of the promising alternatives to alleviate the “range anxiety” of current electric vehicles based on traditional lithium-ion batteries. However, LMBs using traditional liquid electrolytes (LEs) are always facing serious lithium dendrite growth and electrolyte leakage issues, which could usually cause serious safety concerns. Solid polymer electrolytes (SPEs) with high mechanical stability could suppress the lithium dendrites to some extent, however, they are suffering from low ionic conductivity and inferior interfacial contact with electrodes. Gel polymer electrolytes (GPEs) combining the advantages of traditional LEs and SPEs could be a promising choice to alleviate above issues. In this review, we systematically summarized and clarified very recent progress of various advanced GPEs for LMBs, which is mainly focusing on the advancement of different polymer matrices used for GPE-based LMBs as well as the development of methodologies for the preparation of GPEs. In addition, we also provide a perspective aiming at inspiring new ideas and directions to design reliable GPEs for advancing the performance of LMBs and boosting their practical application.

Covalent Organic Frameworks (COFs) have emerged as highly promising materials for the photocatalytic production of hydrogen peroxide (H₂O₂) due to their exceptional structural tunability, robust frameworks, and high porosity. The efficient overall photosynthesis of H₂O₂ hinges on the simultaneous occurrence of the oxygen reduction reaction (ORR) and water oxidation reaction (WOR). This review introduces recent progress in developing key approaches such as backbone engineering and the incorporation of side groups to facilitate these critical reaction pathways. For example, innovative COF designs, such as spatially separating redox centers, have demonstrated significant improvements in photocatalytic performance. Moreover, the introduction of thioether-decorated triazine-based COFs and hexavalent triphenylene knots has led to remarkable H₂O₂ production rates. Furthermore, this review also addresses the challenges associated with the practical implementation of COFs, including their stability under operational conditions and the necessity for innovative reactor designs. The future prospects of COFs in sustainable chemical synthesis are also discussed, emphasizing their potential for COFs to revolutionize H₂O₂ production through green and sustainable methodologies. This review aims to provide valuable insights into the design and development of high-performance COF photocatalysts, paving the way for their practical applications in the sustainable production of value-added chemicals.

In the human body, non-centrosymmetric biological structures exhibit piezoelectric effect across from microscopic biomolecular building blocks to macroscopic tissues and organs. However, the fabrication of piezoelectric devices from discarded natural tissues and organs has rarely been exploited for energy harvesting applications. Herein, the extracted human teeth were recycled as an active layer in a piezoelectric nanogenerator for power generation. Due to the piezoelectric effect of enamel and dentin, a human teeth-based sandwiched piezoelectric nanogenerator was fabricated, producing high and stable power outputs with an open-circuit voltage of approximately 0.9 V under an external force at 60 N. Furthermore, the high mechanical durability of the piezoelectric nanogenerator was also verified after 1600 pressing-and-releasing cycles without noticeable output degradation. Notably, for the first time, a light-emitting diode (LED) was illuminated by the human teeth-based piezoelectric device. This work exemplifies a sustainable strategy to recycle the extracted human teeth by fabricating a piezoelectric nanogenerator for energy harvesting, providing inspiration for converting waste into wealth toward green energy in bionanotechnology.

The perfluorosulfonic acid (PFSA) ionomers are key materials for proton exchange membranes (PEMs) and catalyst layers (CLs). Their morphology is profoundly influenced by the chain assembly behavior of PFSA in dispersions. Hence, we combine the characterization techniques of dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and cryo-transmission electron microscopy (Cryo-TEM) to study the nanostructures of PFSA dispersions, and provide a structure model for diverse PFSA ionomers in water/ethanol solvent. It is seen that PFSA ionomers self-assembly into a rod-like particle in dilute dispersion. As the concentration increases, the primary rod aggregates gradually assemble into a swollen- or Gaussian-network structure. Beyond this feature, we see that different PFSA ionomers show different nanostructures in dispersion. For the long-side-chain (LSC) PFSA ionomers, the 800-LSC PFSA tends to form monodisperse rod-like aggregates that is in a highly ordered arrangement with a rod diameter of 3.16 nm and a length of 28.72 nm. As the equivalent weight (EW) increases to 960, the poor solubility of the main chains in water/ethanol solvents leads to the “end-to-end” assemblies of the primary rod particles and dendritic secondary aggregates. The short-side-chain (SSC) PFSA ionomer that shares the same backbone with 960-LSC PFSA exhibit remarkable mono-dispersity and ordered arrangement of rod-like aggregates in water/ethanol solvents due to the strong electrostatic repulsion.