Latest ArticlesThe excited state dynamics and critically regulated factors of reverse intersystem crossing (RISC) in through-space charge transfer (TSCT) molecules have received insufficient attention. Here, five molecules of through space/bond charge transfer inducing thermally activated delayed fluorescence (TADF) are prepared, and their excited state charge transfer processes are studied by ultrafast transient absorption and theoretical calculations. DM-Z has a larger ∆EST, leading to a longer lifetime of intersystem crossing (ISC), resulting in the lowest photoluminescence quantum yield (PLQY). Oppositely, ISC and RISC are demonstrated to take place with shorter lifetimes for TSCT molecules. The face-to-face π-π stacking interactions and electron communication enable DM-B and DM-BX to have an efficient RISC, increasing the weight coefficient of RISC from 1.7% (DM-X) to close to 50% (DM-B and DM-BX) in the solvents, which make DM-BX and DM-B to have a high PLQY. However, partial local excitation in the donor center is observed and the charge transfer is decreased for DM-G and DM-X. The triplet excited state (DM-G) or singlet excited state (DM-X) mainly undergoes inactivation through a non-radiative relaxation process, resulting in less RISC and low PLQY. This work provides theoretical hints to enhance the RISC process in the TADF materials.
As a kind of emerging energy storage devices, Aqueous zinc ion batteries possess the characteristics of safety, low cost and environmental friendliness. However, their further application is restricted by the sluggish electrochemical reaction kinetics and low conductivity. In this work, we prepare two H3.78V6O13 electrode materials with many active sites, which promotes the kinetics of ion diffusion and then improves the capacity of the cell. The as-obtained HVO-PVP electrode possess a capacity of 393.2 and 285.9 mAh/g at 0.2 and 5.0 A/g, respectively. Moreover, the assembled Zn//HVO-PVP cells also indicate excellent specific capacity and cycle stability at different operating temperatures (0–60 ℃).
TiO2 has been widely studied as one of the most promising anode materials for lithium-ion batteries (LIBs) due to good structural stability and small volume changes. However, its applications are still greatly affected by its poor electrical conductivity. In this work, ultrasmall TiO2 quantum dots (QDs) are firmly grown onto 2D Ti3C2Tx nanosheets (A-TiO2/Ti3C2Tx), benefiting from the positive regulation of (3-aminopropyl)triethoxysilane (APTES). Interestingly, SiO2 nanoparticles produced by the hydrolysis of APTES can strengthen the strong coupling of TiO2 QDs with Ti3C2Tx, thereby enhancing the structural integrity of the composite. As expected, the A-TiO2/Ti3C2Tx composite demonstrates an exceptional lithium storage performance, achieving a high capacity of 425.4 mAh/g for 400 cycles at 0.1 A/g, and an outstanding long-term cycling stability. In-situ electrochemical impedance spectroscopy and theoretical analysis unconver that the superior lithium storage performance is attributed to its unique heterostructure and in-situ N doping derived from APTES, which not only reduces the Li+ adsorption energy, but also gives the fast charge transfer dynamics.
In the practical operations of the sodium ion (Na+) batteries (SIBs), the fast transport of Na+ is desired for the rate performance, because the other ions in an electrolyte are electrochemically inert. In this study, we use molecular dynamics simulations to investigate the partial conductivity of Na+ (σNa+) in the salt-in-ionic liquid electrolytes (SILEs) composed of 1-ethyl-3-methylimidazolium (EMIM+) and bis(fluorosulfonyl)imide (FSI−) with various molar fraction of NaFSI. The simulations show that while the ionic conductivity of the SILE decreases monotonically with the increase of salt fraction of NaFSI, σNa+ peaks in the SILE with 0.5 molar fraction of NaFSI. Detailed analyses indicate that with the increase of salt fraction, the coordination structure of FSI− around Na+ changed from bidentate manner to monodentate manner which weakens the binding of FSI− to Na+. The effects are two folds. On one hand, the increased monodentate coordinations cause a large aggregate that hinders the transport of Na+ within the aggregate; on the other hand, the large aggregate captures most FSI− to form percolating ion network, and thus leaves a small portion of Na+’s that are not in the large aggregate to be more "free" to transport in the SILE.
Mesoporous silica nanoparticles (MSNs) are thought to be an attractive drug delivery material because of their advantages including high specific surface area, tunable pore size and morphology, easy surface modification and good biocompatibility. However, as a result of the poor biodegradability of MSNs, their biomedical applications are limited. To break the bottleneck of limited biomedical applications of MSNs, more and more researchers tend to design biodegradable MSNs (b-MSNs) nanosystems to obtain biodegradable as well as safe and reliable drug delivery carriers. In this review, we focused on summarizing strategies to improve the degradability of MSNs and innovatively proposed a series of advantages of b-MSNs, including controlled cargo release behavior, multifunctional frameworks, nano-catalysis, bio-imaging capabilities and enhanced therapeutic effects. Based on these advantages, we have innovatively summarized the applications of b-MSNs for enhanced tumor theranostics, including enhanced chemotherapy, delivery of nanosensitizers, gas molecules and biomacromolecules, initiation of immune response, synergistic therapies and image-guided tumor diagnostics. Finally, the challenges and further clinical translation potential of nanosystems based on b-MSNs are fully discussed and prospected. We believe that such b-MSNs delivery carriers will provide a timely reference for further applications in tumor theranostics.
Protein glycosylation and phosphorylation, as two of the most important protein post-translational modifications (PTMs), play key roles in living organisms. However, glycopeptides and phosphopeptides have low abundance in biological samples. In addition, the low ionization efficiency and the severe signal interference in the presence of other peptides present great difficulties for their direct mass spectrometry (MS) analysis. Therefore, it is important to develop feasible enrichment strategies to pretreat glycopeptides and phosphopeptides in complex samples before MS detection. This paper reviews the application of various magnetic nanomaterials (MNMs) in glycopeptides and phosphopeptides in the last decade, with emphasis on the enrichment principles, the design and synthesis process of the materials, and the effectiveness of the application in biological samples. In addition, possible future trends and potential challenges are presented.
Nickel-rich cathode materials have received widespread attention due to their high energy density. However, the poor rate capability and inferior cycle stability seriously hinder their large-scale application. The traditional co-precipitation method for preparing them has a long process and easily arises agglomeration leading to inhomogeneous element distribution. Here, a novel precursor containing Li element was prepared by ultrafast spray pyrolysis (SP) in 3–5 s. Then the precursor was used to synthesize pristine LiNi0.9Co0.05Mn0.05O2 (NCM90) and 1% Mg modified LiNi0.9Co0.05Mn0.05O2 (NCM90-Mg1). This method gets rid of mixing Li/Mg source and the precursor prepared by common co-precipitation, thus could achieve homogeneous lithiation and Mg2+ doping. The cell parameter c is expanded, and the cation disorder is reduced after Mg2+ doping. Furthermore, the harmful H2-H3 phase transition in NCM90-Mg1 is also well suppressed. As a result, the obtained NCM90-Mg1 shows better electrochemical performance than NCM90. Within 2.8–4.3 V (25 ℃), the specific discharge capacity of NCM90-Mg1 at 5 C is as high as 169.1 mAh/g, and an outstanding capacity retention of 70.0% (10.0% higher than NCM90) can be obtained after 400 cycles at 0.5 C. At 45 ℃, a capacity retention of 81.9% after 100 cycles at 1 C is recorded for NCM90-Mg1. Moreover, the NCM90-Mg1 also exhibits superior cycle stability when cycled at high cut-off voltage (4.5 V, 25 ℃), possessing the capacity retention of 79.2% after 200 cycles at 1 C. Therefore, SP can be proposed as a powerful method for the preparation of multi-element materials for next-generation high energy density LIBs.
The sluggish reaction kinetics of the oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) remain obstacles to the commercial promotion of water splitting and direct methanol fuel cells. Considering the vital role of noble metals in electrocatalytic activity, this work focuses on the rational synthesis of Ni-noble metal composite nanocatalysts for overcoming the drawbacks of high cost and susceptible oxidized surfaces of noble metals. The inherent catalytic activity is improved by the altered electronic structure and effective active sites of the catalyst induced by the size effect of noble metal clusters. In particular, a series of Ni-noble metal nanocomposites are successfully synthesized by partially introducing noble metal into Ni with porous interfacial defects derived from Ni-Al layered double hydroxide (LDH). The Ni10Pd1 nanocomposite exhibits high OER catalytic activity with an overpotential of 0.279 V at 10 mA/cm2, surpassing Ni10Ag1 and Ni10Au1 counterparts. Furthermore, the average diameter of Pd clusters gradually increases from 5.57 nm to 44.44 nm with the increased proportion of doped Pd, leading to the passivation of catalytic activity due to the exacerbated surface oxidation of Pd in the form of Pd2+. After optimization, Ni10Pd1 delivers significantly enhanced OER and MOR electroactivities and long-term stability compared to that of Ni2Pd1, Ni1Pd1 and Ni1Pd2, which is conducive to the effective utilization of Pd and alleviation of surface oxidation.
Spin-orbit coupling (SOC) plays a vital role in determining the ground state and forming novel electronic states of matter where heavy elements are involved. Here, the prototypical perovskite iridate oxide SrIrO3 is investigated to gain more insights into the SOC effect in the modification of electronic structure and corresponding magnetic and electrical properties. The high pressure metastable orthorhombic SrIrO3 is successfully stabilized by physical and chemical pressures, in which the chemical pressure is induced by Ru doping in Ir site and Mg substitution of Sr position. Detailed structural, magnetic, electrical characterizations and density functional theory (DFT) calculations reveal that the substitution of Ru for Ir renders an enhanced metallic characteristic, while the introduction of Mg into Sr site results in an insulating state with 10.1% negative magnetoresistance at 10 K under 7 T. Theoretical calculations indicate that Ru doping can weaken the SOC effect, leading to the decrease of orbital energy difference between J1/2 and J3/2, which is favorable for electron transport. On the contrary, Mg doping can enhance the SOC effect, inducing a metal-insulator-transition (MIT). The electronic phase transition is further revealed by DFT calculations, confirming that the strong SOC and electron-electron interactions can lead to the emergence of insulating state. These findings underline the intricate correlations between lattice degrees of freedom and SOC in determining the ground state, which effectively stimulate the physical pressure between like structures by chemical compression.
With the development of science and technology, there is an increasing demand for energy storage batteries. Aqueous zinc-ion batteries (AZIBs) are expected to become the next generation of commercialized energy storage devices due to their advantages. The aqueous zinc ion battery is generally composed of zinc metal as the anode, active material as the cathode, and aqueous electrolyte. However, there are still many problems with the cathode/anode material and voltage window of the battery, which limit its use. This review introduces the recent research progress of zinc-ion batteries, including the advantages and disadvantages, energy storage mechanisms, and common cathode/anode materials, electrolytes, etc. It also gives a summary of the current research status of each material and provides solutions to the problems they face. Finally, it looks at the future direction and methods to optimize the performance of zinc-ion full batteries.