Full-color persistent room temperature phosphorescent elastomers with robust optical properties.

Persistent room temperature phosphorescent materials with unique mechanical properties and robust optical properties have great potential in flexible electronics and photonics. However, developing such materials remains a formidable challenge. Here, we present highly stretchable, lightweight, and multicolored persistent luminescence elastomers, produced by incorporating ionic room temperature phosphorescent polymers and polyvinyl alcohol into a polydimethylsiloxane matrix. These prepared elastomers exhibit high optical transparency in daylight and emit bright persistent luminescence after the removal of 365 nm excitation. The homogeneous distribution of polymers within the matrix has been confirmed by confocal fluorescence microscopy, scanning electron microscopy, and atomic force microscopy. Mechanical property investigations revealed that the prepared persistent luminescence elastomers possess satisfactory stretchability. Impressively, these elastomers maintain robust optical properties even under extensive and repeated mechanical deformations, a characteristic previously unprecedented. These fantastic features make these persistent luminescence elastomers ideal candidates for potential applications in wearable devices, flexible displays, and anti-counterfeiting.

NIR-Triggered On-Demand Nitric Oxide Release for Enhanced Synergistic Phototherapy of Hypoxic Tumor.

Hypoxia of tumor microenvironments is a major factor restricting tumor treatment, which causes progression and metastasis of tumor. The hypoxic tumor microenvironment not only makes the traditional treatment method, such as chemotherapy, ineffective but also hinders the O2-dependent treatments, such as photodynamic therapy (PDT). Recently, stimuli-responsive nitric oxide (NO) donors have attracted extensive research interest in hypoxic tumor treatment because the NO release process is O2-independent. Besides, NO can distribute more uniformly than drug molecules and more widely than the PDT-generated active species due to its strong diffusion ability (200 µm in cells) and long lifetime (2 s in cells). Encouraged by these advantages, a near infrared light-triggered NO release polymeric nanoplatform (P1-CapNO NPs) was constructed by a thermally sensitive NO release unit, a photothermal unit, and a hydrophilic polyethylene glycol unit. P1-CapNO NPs possess strong absorption in the NIR region (the wavelength of maximal absorption peak was 790 nm with a molar absorption coefficient of 2.4 × 105 M-1 cm-1), great photothermal conversion efficiency (23.8%), and NO release ability (the released NO concentration can reach 1.3 µM) under 808 nm laser irradiation. Owing to these advantages, the great synergistic antitumor effect can be achieved in vitro and in vivo even under the hypoxic environment. The synergistic therapeutic strategy in this work could bypass the obstacles caused by hypoxia in tumor treatment and provide a reference for building a NO-involved therapeutic platform.

Stabilizing sulfur vacancy defects by performing "click" chemistry of ultrafine palladium to trigger a high-efficiency hydrogen evolution of MoS2.

Defect engineering is widely applied in transition metal dichalcogenides to produce high-purity hydrogen. However, the instability of vacancy states on catalysis still remains a considerable challenge. Here, our first-principles calculations showed that, by optimizing the asymmetric S vacancy in the highly asymmetric 1T' crystal of layered bitransition metal dichalcogenides (Co-MoS2) in light of Pd modulation, the relative amount of metastable phase and the quantity of active sites in the structure can be reduced and increased, respectively, leading to a further boosted hydrogen evolution reaction (HER) activity toward layered bi-transition metal dichalcogenides. Thus, we then used a "click" chemistry strategy to make such a catalyst with engineered unsaturated sulfur edges via a strong coupling effect between ultrafine Pd ensembles and Co-MoS2 nanosheets. As expected, the Pd-modulated Co-MoS2 nanosheets exhibited a very low overpotential of 60 mV at 10 mA cm-2 with a small Tafel slope (56 mV dec-1) for the HER in 1.0 M PBS, comparable to those of commercial Pt/C. In addition, their high HER activity was retained in acidic and alkaline conditions. Both the theoretical and experimental results revealed that Pd ensembles can efficiently activate and stabilize the inert basal plane S sites during HER processes as a result of the formation of Pd-S in Co-MoS2. This work not only provides a deeper understanding of the correlation between defect sites and intrinsic HER catalytic properties for transition metal chalcogenide (TMD)-based catalysts, but also offers new insights into better designing earth-abundant HER catalysts displaying high efficiency and durability.

Phosphorus-triggered synergy of phase transformation and chalcogenide vacancy migration in cobalt sulfide for an efficient oxygen evolution reaction.

Introduction of surface defects and phase control engineering in the electrocatalytic system of overall water splitting has played a crucial role in significantly enhancing its electrocatalytic activity toward the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in water splitting, but the relationship between structure and electrocatalysis is still elusive. Herein, we report a solid-liquid method to induce surface reorganization (formation of a chalcogenide layer with rich chalcogenide vacancies) and phase transformation (Co9S8-to-Co3S4) simultaneously on cobalt chalcogenide. Featuring a uniform 2D morphology and the in situ formation of sulfur (S) vacancies, in a 0.1 M KOH solution, it exhibits a low overpotential of 288 mV vs. RHE at 10 mA cm-2, a low Tafel slope of 43.4 mV dec-1, and strong cycling stability (35 h), outperforming commercial RuO2 and most reported OER electrocatalysts. In addition, we also investigate the OER activity of the Co-S-P electrode in 1.0 M KOH solutions. Co0.37S0.38P0.02 NSs only need 257 mV to reach a current density of 10 mA cm-2. Meanwhile, the Tafel slope of Co0.37S0.38P0.02 NSs (44.0 mV dec-1) is lower than those of other recently reported electrocatalysts. Also, it shows high HER electrocatalytic activity in alkaline and acidic solutions. Finally, the Co0.37S0.38P0.02 electrode is used as a cathode and anode simultaneously for overall water splitting, which merely requires a cell voltage of 1.59 V at 10 mA cm-2 with excellent stability (40 h).