Intramolecular through‐space charge‐transfer (TSCT) excited states have been exploited for developing thermally activated delayed fluorescence (TADF) emitters, but the tuning of excited state ...dynamics by conformational engineering remains sparse. Designed here is a series of TSCT emitters with precisely controlled alignment of the donor and acceptor segments. With increasing intramolecular π–π interactions, the radiative decay rate of the lowest singlet excited state (S1) progressively increased together with a suppression of nonradiative decay, leading to significantly enhanced photoluminescence quantum yields of up to 0.99 in doped thin films. A high‐efficiency electroluminescence device, with a maximum external quantum efficiency (EQE) of 23.96 %, was achieved and maintains >20 % at a brightness of 1000 cd m−2. This work sheds light on the importance of conformation control for achieving high‐efficiency intramolecular exciplex emitters.
The orientations of donor and acceptor have been controlled for the development of thermally activated delayed fluorescence emitters featuring intramolecular through‐space charge‐transfer excited states. With maximized cofacial π–π interactions between the quasiplanar donor and acceptor segments, a substantial enhancement of radiative decay rate together with a suppressed nonradiative decay resulted in an emission efficiency of almost unity.
Materials exhibiting excitation wavelength‐dependent photoluminescence (Ex‐De PL) in the visible region have potential applications in bioimaging, optoelectronics and anti‐counterfeiting. Two ...multifunctional, chiral Au(NHC)2Au(CN)2 (NHC=(4R,5R)/(4S,5S)‐1,3‐dimethyl‐4,5‐diphenyl‐4,5‐dihydro‐imidazolin‐2‐ylidene) complex double salts display Ex‐De circularly polarized luminescence (CPL) in doped polymer films and in ground powder. Emission maxima can be dynamically tuned from 440 to 530 nm by changing the excitation wavelength. The continuously tunable photoluminescence is proposed to originate from multiple emissive excited states as a result of the existence of varied AuI⋅⋅⋅AuI distances in ground state. The steric properties of the NHC ligand are crucial to the tuning of AuI⋅⋅⋅AuI distances. An anti‐counterfeiting application using these two salts is demonstrated.
Ex‐De CPL: By modulating the strength of AuI⋅⋅⋅AuI and Coulombic interactions by adjusting steric hindrance of the ligand, together with the materials processing, the two chiral enantiomers of Au(NHC)2Au(CN)2 double salts in PMMA film or as ground powder exhibit mirror‐image excitation wavelength‐dependent photoluminescence (Ex‐De CPL).
Photocatalytic hydrogen evolution from pure water is successfully realized by using interstitial P‐doped CdS with rich S vacancies (CdS‐P) as the photocatalyst in the absence of any electron ...sacrificial agents. Through interstitial P doping, the impurity level of S vacancies is located near the Fermi level and becomes an effective electron trap level in CdS‐P, which can change dynamic properties of photogenerated electrons and thus prolong their lifetimes. The long‐lived photogenerated electrons are able to reach the surface active sites to initiate an efficient photocatalytic redox reaction. Moreover, the photocatalytic activity of CdS‐P can be further improved through the loading of CoP as a cocatalyst.
Photocatalytic hydrogen evolution from pure water is realized by CdS‐P. Through interstitial P doping, the impurity level of S vacancies is located near the Fermi level and becomes an effective electron trap level, which can change the dynamics of photogenerated electrons. The long‐lived photogenerated electrons can reach the surface active sites for initiating the photocatalytic reaction.
Toll-like receptors (TLRs) are a well-known family of pattern recognition receptors that play an important role in a host immune system. TLR triggering leads to the induction of pro-inflammatory ...cytokines and chemokines, driving the activation of both innate and adaptive immunity. Recently, an increasing number studies have shown the link between TLRs and cancer. Among them, the toll-like receptor 4 (TLR4) signaling pathway is associated with inflammatory response and cancer progression. Dietary phytochemicals are potential modulators of immunological status with various pharmacological properties including anti-cancer, anti-oxidant and anti-inflammatory. Curcumin, 6-gingerol, 6-shogaol, 1-dehydro-10-gingerdione, epigallocatechin gallate (EGCG), luteolin, quercetin, resveratrol, caffeic acid phenethyl ester, xanthohumol, genistein, berberine, and sulforaphane can inhibit TLR4 activation. The aim of the present review is to describe the role of the TLR4 signaling pathway between inflammatory response and cancer progression. We further introduce bioactive phytochemicals with potential anti-inflammation and chemoprevention by inhibiting TLR activation.
In recent years a blossoming interest in the synthesis, photophysics and application of phosphorescent Pt(ii) complexes, particularly on their uses in bioimaging, photocatalysis and phosphorescent ...organic light-emitting diodes (OLEDs), has been witnessed. The superior performance of phosphorescent Pt(ii) complexes in these applications is linked to their diverse spectroscopic and photophysical properties, which can be systematically modulated by appropriate choices of auxiliary ligands. Meanwhile, an important criterion for the practical application of phosphorescent metal complexes is their stability which is crucial for biological utilization and industrial OLED applications. Taking both the luminescence properties and stability into consideration, chelating ligands having rigid scaffolds and with strong σ-donor atoms are advantageous for the construction of highly robust phosphorescent Pt(ii) complexes. The square-planar coordination geometry endows Pt(ii) complexes with the intriguing spectroscopic and photophysical properties associated with their intermolecular interactions in both the ground and excited states. In this article, we discuss the design and synthesis of phosphorescent Pt(ii) complexes with elaboration on the effects of ligands on the structure and luminescence properties. Based on their photophysical and emission properties, we intend to shed light on the great promise of highly robust phosphorescent Pt(ii) emitters in an array of applications from molecular materials to biosensors.
Self‐assembled functional nanoarchitectures are employed as important nanoscale building blocks for advanced materials and smart miniature devices to fulfill the increasing needs of high materials ...usage efficiency, low energy consumption, and high‐performance devices. One‐dimensional (1D) crystalline nanostructures, especially molecule‐composed crystalline nanostructures, attract significant attention due to their fascinating infusion structure and functionality which enables the easy tailoring of organic molecules with excellent carrier mobility and crystal stability. In this review, we discuss the recent progress of 1D crystalline self‐assembled nanostructures of functional molecules, which include both a small molecule‐derived and a polymer‐based crystalline nanostructure. The basic principles of the molecular structure design and the process engineering of 1D crystalline nanostructures are also discussed. The molecular building blocks, self‐assembly structures, and their applications in optical, electrical, and photoelectrical devices are overviewed and we give a brief outlook on crucial issues that need to be addressed in future research endeavors.
Recent progress in self‐assembled 1D crystalline nanostructures of functional molecules is discussed, with both small‐molecule‐based crystalline nano structures and functional‐polymer self‐assembled 1D nanostructures. The molecular building blocks, the selfassembled structures, and applications in optical, electrical, and photoelectrical devices are overviewed and a brief outlook on crucial issues that need to be addressed in future research endeavors is given .
Luminescent ratiometric thermometers (LRTs) based on the emission intensity ratio with self‐reference functions guarantee a temperature sensing of fast response, high precision, and excellent spatial ...resolution. For monitoring temperature at the cellular level, the use of metal–organic frameworks (MOFs) as probes, especially biocompatible ones, is still in its nascency. By employing a biological MOF, Zn3(benzene‐1,3,5‐tricarboxyl)2(adenine)(H2O) (ZnBTCA), as a host and thermosensitive fluorescent dyes as guests, a series of dye@ZnBTCA is synthesized and studied as potential LRT materials, featuring a unique mechanism of tandem Förster resonance energy transfer among the MOF host and the multiple dye guests. This scenario is significantly different from the commonly reported lanthanide or mixed‐lanthanide MOFs where energy transfer occurs between lanthanide ions. Acf‐RB@ZnBTCA, in particular, not only exhibits highly efficient ratiometric temperature‐sensing properties under physiological cellular conditions but also can be excited under visible light.
A series of dye@ZnBTCA where ZnBTCA is Zn3(benzene‐1,3,5‐tricarboxyl)2(adenine)(H2O) is synthesized and thoroughly studied as potential luminescent ratiometric thermometer (LRT) probes, featuring a mechanism of tandem Förster resonance energy transfer between the metal–organic framework (MOF) and the mixed dye. The mixed‐dye@ZnBTCA is shown to be a self‐referenced LRT, which is both biocompatible and excitable by visible light for monitoring temperature at the cellular level.
Photonic circuit systems based on optical waveguiding heteroarchitectures have attracted considerable interest owing to their potential to overcome the speed limitation in electronic circuits by ...modulating the optical signal at the micro‐ or nanoscale. However, controlling the parameters, including the wavelength and polarization of the light outcoupling, as well as the sequence among different building blocks, remains a key issue. Herein, supramolecular heteroarchitectures made by phosphorescent organometallic complexes of Pt, Pd, Cu, and Au are applied as photonic logic gates that show continuously variable emission colors from 475 to 810 nm, low waveguide losses down to 0.0077 dB µm−1, and remarkable excitation‐light polarization‐dependent photoluminescence with anisotropy ratios up to 0.68. The sequences among Pt, Pd, Au, and Cu building blocks in the heteroarchitectures are controlled by living supramolecular polymerization or crystallization‐driven self‐assembly synthetic approaches. The results indicate the prospects for using organometallic complexes and supramolecular synthetic approaches to prepare photonic circuit systems with tunable emission color and controllable sequences among different blocks that achieve modulation of the optical signal in the visible‐to‐near‐infrared spectral region.
An input‐to‐output photonic logic gate is fabricated based on supramolecular heterostructures by phosphorescent Pt, Pd, Au, and Cu organometallic complexes. It is based on the optical waveguiding effect and efficient energy transfer among different blocks. The photonic logic gates show high emission anisotropy, low optical waveguiding loss, and continuously varied emission colors in the visible‐to‐near‐infrared spectral region.
Two-dimensional (2D) van der Waals ferromagnets carry the promise of ultimately miniature spintronics and information storage devices. Among the 2D ferromagnets, all inherit the magnetic ordering ...from their bulk ancestors. Here we report a 2D ferromagnetic semiconductor at room temperature, 2H-phase vanadium diselenide (VSe2), which shows ferromagnetic at the 2D form only. This 2D ferromagnetic semiconductor manifests an enhanced magnetic ordering owing to structural anisotropy at the 2D limit.
Psoriasis is a common non-contagious chronic inflammatory skin lesion, with frequent recurrence. It mainly occurs due to aberrant regulation of the immune system leading to abnormal proliferation of ...skin cells. However, the pathogenic mechanisms of psoriasis are not fully understood. Although most of the current therapies are mostly efficient, the side effects can result in therapy stop, which makes the effectiveness of treatment strategies limited. Therefore, it is urgent and necessary to develop novel therapeutics. Here, we investigated the efficacy of chrysin, a plant flavonoid, which we previously reported to possess strong antioxidant and anti-inflammatory effects, against psoriasis-like inflammation. Our results revealed that chrysin significantly attenuated imiquimod-induced psoriasis-like skin lesions in mice, and improved imiquimod-induced disruption of skin barrier. Moreover, the TNF-α, IL-17A, and IL-22-induced phosphorylation of MAPK and JAK-STAT pathways, and activation of the NF-κB pathway were also attenuated by chrysin pretreatment of epidermal keratinocytes. Most importantly, chrysin reduced TNF-α-, IL-17A-, and IL-22-induced CCL20 and antimicrobial peptide release from epidermal keratinocytes. Thus, our findings indicate that chrysin may have therapeutic potential against inflammatory skin diseases. Our study provides a basis for further investigating chrysin as a novel pharmacologic agent and contributes to the academic advancement in the field of Chinese herbal medicine.
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