Controlling the efficient emission of organic luminogens in both monomeric and various aggregated states remains a challenging task. In this work, the motion of an organic luminophores is synergistically regulated by introducing side alkyl chains with appropriate length and the aromatic rotor triphenylamine. This study finds that the incorporation of alkyl chains not only increased the rotational barriers in the molecule, but also influenced the packing modes. The as-prepared organic luminogen, FIMPA-C6, exhibited bright emissions in solution, polymorph, and amorphous states. Furthermore, the emission of FIMPA-C6 can be widely tuned from yellow to deep red in different aggregated states. The exceptional luminescent properties of FIMPA-C6 make it a promising functional dye for cellular imaging applications. A novel organic luminogen, FIMPA-C6, is being developed by adopting side-chain engineering and rotors to synergistically regulate molecular motion. FIMPA-C6 demonstrates intense emission in solution, polymorph, and amorphous states. The introduction of side-chain engineering induces polymorphism and imparts remarkable mechanochromic fluorescence properties to FIMPA-C6. The exceptional luminescent properties highlight the potential of FIMPA-C6 as a functional dye for bioimaging applications. image

A new three-dimensional Zn(II) complex named [Zn(1,3-BMIB)(TBIP)⋅2H 2 O][Formula: see text] (1) (containning 1,3-BMIB = 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene, H 2 TBIP=5-tert-butyl isophthalic acid) had been prepared by hydrothermal synthesis. Systematic structural characterization, especially the single crystal X-ray diffraction method, discreetly reveal the complex 1 exhibits three-dimensional (3D) framework with CdSO 4 topology. The 3D crystrals 1 display solid-state fluorescence behavior at room temperature, indicating the potential of the candidate materials for absorbing and using visible light. The photocatalytic properties of compound 1 were estimated through the model photodecomposition dye pollutants using methylene blue (MB) and rhodamine B (RhB) under visible light irradiation.

Patients suffering from alopecia areata often have limited therapeutic options for anti-hair loss. Compared with hair transplant and oral finasteride, therapy with fewer side effects for alopecia areata has been explored. Herein, a facile minoxidil (MNX) loaded porous UiO-66 microneedle (MN) patch enabling realize rapid-release of UiO-66 and slow-release of MNX simultaneously is reported. The MN patch is composed of polylactic acid (PLA) substrate and hyaluronic acid (HA) MN arrays. Once being inserted under the skin, HA-MN arrays would dissolve rapidly and MNX-loaded UiO-66 releases concurrently in a short time, followed by MNX releasing from UiO-66 continuously under the skin. The therapeutic schedule could reduce the use time and frequency of MN patches effectively to lower the negative effects brought to the patients by the treatment, such as risk of bacterial infection and aesthetic degree of wearing. UiO-66 loaded MN patches present antibacterial activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) to avoid bacterial infection during use. PLA substrate provides enough mechanical property to remove the patches entirely after using. After the fabricated MNX-loaded PLA/HA-MNs being inserted, the patches induced the high level of I kappa B alpha and low level of p-P65 in the topical treatment via mice model, thus inhibiting the phosphorylation of NF-kappa B (NF-kappa B) pathway. Collectively, this smart drug slow-release system promotes the safety and effectiveness of treatment for alopecia areata, thus exhibiting potential applications for hair loss.

采用共沉淀法耦合溶胶-凝胶法制备了核壳结构的磁性颗粒Fe3O4@SiO2@TiO2,将其负载在活性炭(AC)表面,制得新型光催化剂Fe3O4@SiO2@TiO2-AC.采用SEM、FTIR、XRD、VSM对材料进行表征,并探究该催化剂对水中腐殖酸(HA)的去除效能.结果表明,以400 W高压汞灯作为光源,投加量为200 mg/L时,60 min内对初始质量浓度为5 mg/L、pH为7的含HA水样去除率可达96.1％.Fe3O4@SiO2@TiO2-AC对HA的光催化降解符合Langmuir-Hinshelwood(L-H)动力学模型.Fe3O4@SiO2@TiO2与AC存在协同作用,可有效增强复合光催化剂的催化效能.材料具有较好的催化稳定性,5次重复使用后,对水样中HA的去除率仍能达到84.7％.

Light-harvesting complex II (LHCII) – the light-harvesting antenna of Photosystem II – is a naturally abundant system that plays an important role in photosynthesis. In this study, we present a phenomenological analysis of the excitonic energy transfer in LHCII using ultrafast two-dimensional electronic spectroscopy, that we find compares well with previous theoretical and experimental results.

We use ultrafast coherent two-dimensional electronic spectroscopy (2DES) to study the ultrafast spectral diffusion dynamics of colloidal CdSe quantum dots (QDs) and CdSe nanoplatelets (NPLs). The Center Line Slope (CLS) and Nodal Line Slope (NLS) techniques were employed to analyse the 2DES spectra. We show that no spectral diffusion dynamics occurs for the CdSe QDs. On the other hand, spectral diffusion was observed in the CdSe 5 mono-layers NPLs heavy-hole transition. The normalized Frequency Fluctuation Correlation Function (FFCF) of the CdSe NPLs heavy-hole transition was measured to have a major fast decay component at 140 fs.

Photosystem I is a robust and highly efficient biological solar engine. Its capacity to utilize virtually every absorbed photon’s energy in a photochemical reaction generates great interest in the kinetics and mechanisms of excitation energy transfer and charge separation. In this work, we have employed room-temperature coherent two-dimensional electronic spectroscopy and time-resolved fluorescence spectroscopy to follow exciton equilibration and excitation trapping in intact Photosystem I complexes as well as core complexes isolated from Pisum sativum . We performed two-dimensional electronic spectroscopy measurements with low excitation pulse energies to record excited-state kinetics free from singlet–singlet annihilation. Global lifetime analysis resolved energy transfer and trapping lifetimes closely matches the time-correlated single-photon counting data. Exciton energy equilibration in the core antenna occurred on a timescale of 0.5 ps. We further observed spectral equilibration component in the core complex with a 3–4 ps lifetime between the bulk Chl states and a state absorbing at 700 nm. Trapping in the core complex occurred with a 20 ps lifetime, which in the supercomplex split into two lifetimes, 16 ps and 67–75 ps. The experimental data could be modelled with two alternative models resulting in equally good fits—a transfer-to-trap-limited model and a trap-limited model. However, the former model is only possible if the 3–4 ps component is ascribed to equilibration with a “red” core antenna pool absorbing at 700 nm. Conversely, if these low-energy states are identified with the P 700 reaction centre, the transfer-to-trap-model is ruled out in favour of a trap-limited model.

In this work, a novel hybrid flow battery system is proposed. In the negative side, we explore a vitamin-based molecule that has never been tested in a flow battery before. As a quinone derivative, it undergoes a reversible two-electron redox reaction at 0.05 V vs. standard hydrogen electrode. The solubility of the molecule is higher than 4.5 M, leading to a volumetric energy density of 120 Wh/L, when paired with a lead dioxide/lead sulfate electrode [1]. Such a hybrid flow battery achieves a cell voltage of 1.68 V and can be cycled stably for over 50 cycles without significant capacity loss. The adoption of solid-state lead-based electrode eliminates the need of an expensive ion exchange membrane. More importantly, as the molecule has been mass-produced at low cost, the cost of this novel system is much lower than current existing flow battery systems [2-3]. It is a promising candidate for both large scale energy storage usages and mobile applications in both perspectives of cost and energy density. [1] Leung, P. K., Qian Xu, and T. S. Zhao. "High-potential zinc–lead dioxide rechargeable cells." Electrochimica Acta 79 (2012): 117-125. [2] Zhang, Mengqi, et al. "Capital cost sensitivity analysis of an all-vanadium redox-flow battery." Journal of The Electrochemical Society 159.8 (2012): A1183-A1188. [3] Zeng, Y. K., et al. "A comparative study of all-vanadium and iron-chromium redox flow batteries for large-scale energy storage." Journal of Power Sources 300 (2015): 438-443.

Excited-state relaxation dynamics and energy-transfer processes in the chlorophyll a (Chl a) manifold of the light-harvesting complex II (LHCII) were examined at physiological temperature using femtosecond two-dimensional electronic spectroscopy (2DES). The experiments were done under conditions free from singlet-singlet annihilation and anisotropic decay. Energy transfer between the different domains of the Chl a manifold was found to proceed on time scales from hundreds of femtoseconds to five picoseconds, before reaching equilibration. No component slower than 10 ps was observed in the spectral equilibration dynamics. We clearly observe the bidirectional (uphill and downhill) energy transfer of the equilibration process between excited states. This bidirectional energy flow, although implicit in the modeling and simulation of the EET processes, has not been observed in any prior transient absorption studies. Furthermore, we identified the spectral forms associated with the different energy transfer lifetimes in the equilibration process.

We describe a model to explain the features of the ultrafast transient absorption (TA) spectra of CdSe core type quantum dots (QDs). The measured TA spectrum consists of contributions by the ground state bleach (GSB), stimulated emission (SE) and excited state absorption (ESA) processes associated with the three lowest energy transition of the QDs. We model the shapes of the GSB, SE and ESA spectral components after fits to the linear absorption. The spectral positions of the ESA components take into account the biexcitonic binding energy. In order to obtain the correct weightage of the GSB, SE and ESA components to the TA spectrum, we enumerate the set of coherence transfer pathways associated with these processes. From our fits of the experimental TA spectra of 65Å diameter QDs, biexcitonic binding energies for the three lowest energy transitions are obtained.

The pathways and dynamics of excitation energy transfer between the chlorophyll (Chl) domains in solubilized trimeric and aggregated light-harvesting complex II (LHCII) are examined using two-dimensional electronic spectroscopy (2DES). The LHCII trimers and aggregates exhibit the unquenched and quenched excitonic states of Chl a, respectively. 2DES allows direct correlation of excitation and emission energies of coupled states over population time delays, hence enabling mapping of the energy flow between Chls. By the excitation of the entire Chl b Qy band, energy transfer from Chl b to Chl a states is monitored in the LHCII trimers and aggregates. Global analysis of the two-dimensional (2D) spectra reveals that energy transfer from Chl b to Chl a occurs on fast and slow time scales of 240-270 fs and 2.8 ps for both forms of LHCII. 2D decay-associated spectra resulting from the global analysis identify the correlation between Chl states involved in the energy transfer and decay at a given lifetime. The contribution of singlet-singlet annihilation on the kinetics of Chl energy transfer and decay is also modelled and discussed. The results show a marked change in the energy transfer kinetics in the time range of a few picoseconds. Owing to slow energy equilibration processes, long-lived intermediate Chl a states are present in solubilized trimers, while in aggregates, the population decay of these excited states is significantly accelerated, suggesting that, overall, the energy transfer within the LHCII complexes is faster in the aggregated state.