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A bottom-contact organic field-effect transistor (OFET) is easily adaptable to the standard lithography process because the contact electrodes are deposited before the organic semiconductor (OSC). However, the low surface energy of bare electrodes limits utilizing solution-processed single-crystal OSCs. Additionally, the bare electrode usually leads to a significant charge injection barrier, owing to its relatively low work function (WF). Here, we simultaneously improved the surface energy and WF of gold electrodes by conducting oxygen plasma treatment to achieve high-performance OFET based on solution-processed organic single crystals. We cultivated a thin layer of gold oxide on Au electrodes to increase the WF by ∼0.7 eV. The surface energy of Au electrodes was enhanced to the same as AlO x dielectric surface, enabling the seamless growth of large-area C 8 -BTBT (2,7-dioctyl[1]benzothieno[3,2- b ][1]benzothiophene) organic single-crystal thin films via solution shearing. This technique facilitates the production of high-performance OFETs with the highest carrier mobility of 6.7 cm 2 V -1 s -1 and sharp switching characterized by a subthreshold swing of 63.6 mV dec -1 . The bottom-contact OFETs exhibited a lower contact resistance of 1.19 kΩ cm than its F 4 -TCNQ-doped top-contact control device. This method offers a straightforward and effective strategy for producing high-quality single-crystal OFETs, which are potentially suitable for commercial applications.

Sonosensitizers play crucial roles in the controlled production of reactive oxygen species (ROS) under ultrasound (US) irradiation with high tissue-penetration depth for noninvasive solid tumor therapy. It is desirable to fabricate structurally simple yet multifunctional sonosensitizers from ultrafine nanoparticles for ROS-based multimode therapy to overcome monomode limitations such as low ROS production yields and endogenous reductive glutathione (GSH) to ROS-based treatment resistance. We report the facile high-temperature solution synthesis of ultrafine W-doped TiO 2 (W-TiO 2 ) nanorods for exploration of their sonodynamic, chemodynamic, and GSH-depleting activities in sonodynamic-chemodynamic combination tumor therapy. We found that W 5+ and W 6+ ions doped in W-TiO 2 nanorods play multiple roles in enhancing their ROS production. First, W doping narrows the band gap from 3.2 to 2.3 eV and introduces oxygen and Ti vacancies for enhancing their sonodynamic performance. Second, W 5+ doping endows W-TiO 2 nanorods with Fenton-like reaction activity to produce •OH from endogenous H 2 O 2 in the tumor. Third, W 6+ ions reduce endogenous GSH to glutathione disulfide (GSSG) and, in turn, form W 5+ ions that further enhance their chemodynamic activity, which greatly modifies thae oxidation-reduction tumor microenvironment in the tumor. In vivo experiments display the excellent ability of W-TiO 2 nanorods for enhanced tumor eradication in human osteosarcoma models under single US irradiation. Importantly, the ultrafine nanorod morphology facilitates rapid excretion from the body, displaying no significant systemic toxicity. Our work suggests that multivalent metal doping in ultrafine nanomaterials is an effective and simple strategy for the introduction of new functions for ROS-based multimode therapy.

Metal-free layered black phosphorus (BP) nanosheets with an excellent photothermal effect and large surface areas have been widely applied in biomedicine but are easily oxidized in ambient conditions yielding insulating phosphorus oxides adsorbed on its surface. Several chemical-functionalized strategies have been explored to protect thin layers of BP; however, the performance of passivated BP often decreases significantly, falling behind the single BP due to the strong structure perturbation. Herein, we designed and constructed 0D/2D hybrid photothermal agents by assembling NIR-II-responsive carbon dots (NIR-II-CDs) on BP nanosheets. NIR-II-CDs improve the ambient stability of BP by isolating them from water and oxygen and enhance the photothermal properties of BP nanosheets. Such NIR-II-CD/BP hybrids strengthen the light-harvesting ability, achieving high photothermal conversion efficiencies in the NIR-I (77.3%) and NIR-II (61.4%) windows, which is significantly higher than that of pristine BP (49.5 and 28.4% at 808 and 1064 nm). Owing to the intrinsic advantage of 1064 nm laser and the excellent PTT effect of our NIR-II-CD/BP hybrids, complete tumor eradication was realized in a deep-tissue tumor model.

Luminescent nanoparticles with dual-mode long-lived luminescence are of great importance for their attractive applications in biosensing, bioimaging, and data encoding. Herein, we report the realization of up- and downconversion emission of Mn 2+ dopants in multilayer nanoparticles of NaGdF 4 :Yb/Tm@NaGdF 4 :Ce/Mn@NaYF 4 upon excitation at 980 and 254 nm, respectively. The dual-mode emission of the Mn 2+ dopants at 531 nm have a long-lived lifetime up to ∼30 ms as a result of the spin-forbidden optical transition of Mn 2+ within the 3d 5 configuration. After ceasing steady excitation at the two wavelengths, the long-lived feature of Mn 2+ luminescence allows a longer persistent time than lanthanide emissions, thereby enabling the ease of data decoding by a cell phone camera under a burst mode. The long-lived green upconversion emission also permits the generation of a long green tail emission upon dynamic excitation at 980 nm. These attributes make the as-prepared Mn 2+ -doped multilayer nanoparticles particularly attractive for multilevel anticounterfeiting.

The ability to reversibly manipulate the surface nature of luminescent nanoparticles upon external stimulation enables the development of advanced optical probes for biological sensing and data encoding. Herein, we report the synthesis of a new class of smart carbon dots (CDs) via surface modification of amine-enriched CDs with CO 2 -responsive groups of amidine. We present that alternative CO 2 and N 2 bubbling can not only lead to a reversible phase transfer of the CDs between an organic phase and an aqueous phase but also give rise to a corresponding reversible luminescence change between blue and cyan-green. We attribute these observations to changes in both the surface chemistry and the emission states of the CDs triggered by the alternative CO 2 /N 2 introduction. We also find a similar luminescence change of the CDs upon alternative exposure to a humid vapor of CO 2 and a mixture of NH 3 and N 2 at room temperature, allowing them to be used as a new class of optical materials for optical encoding.

In the synthesis of Au/Pd bimetallic nanocrystals, a layer-by-layer growth is favored, owing to the low bonding energy between Pd atoms ( E Pd-Pd ) in comparison with E Au-Pd , resulting in homogeneous core/shell nanostructures. Herein, we demonstrate designed synthetic tactics to unconventional Au/Pd heterostructures through a deposition-dominant growth pathway of the newly reduced Pd atoms, which break the intrinsically favored layer-by-layer growth. Pd thus grows on Au seeds in a heterogeneous nucleation manner. The resulting anisotropic Pd nanorods array on the two basal facets and three side facets of the Au triangular seeds in a high density to form 2D/1D Au/Pd heterostructures. It is noticed that Pd nanorods align in an extremely high order. They grow almost in a row with the base of the rod located overlapped on the Au surface. This versatile approach has been also applied to other Au nanocrystal seeds, involving hexagonal nanoplates, circular nanodisks, nanorods, and nanobipyramids. Furthermore, the 2D/1D Au/Pd heterostructures exhibit an enhanced electrocatalytic performance toward ethanol oxidation in alkaline condition, owing to their unique structure and the exposure of Au. We believe that our synthetic strategy is highly valuable for the construction of multimetallic nanostructures with desired architectures and thus intriguing properties.

Synthesis of hollow metal nanocrystals (NCs) is greatly attractive for their high active surface areas, which gives rise to excellent catalytic activity. Taking PdPt alloy nanostructure as an example, we designed a synthetic tactic for the preparation of hollow metal nanostructures by delicate control over the difference in the reduction kinetic of metal precursors. At a high reduction rate difference, the Pd layer forms from H 2 PdCl 4 and is subsequently etched, leading to the formation of a hollow space. A solid PdPt structure is achieved when the reduction rate of Pd and Pt precursor is comparable. Obviously, the hollow space and composition are tunable as well by adjusting the reduction rate difference. More importantly, the prepared hollow PdPt nanostructures exhibit a branched outer, porous wall, and rough hollow interior. The branched outer and rough hollow interior provide the higher density of unsaturated atoms, whereas the porous wall serves as channels connecting the inner, outer, and reactive agents. Moreover, the periodic self-consistent density function theory suggests that the d-band theory density of state of the PdPt nanoalloys is upshifted in comparison to the monometallic component, which will beneficial for improvement in their catalytic performances. Electrocatalytic tests reveal that the PdPt bimetallic NCs, especially for Pt 32 Pd 68 nanostructures, show excellent catalytic activity and stability toward methanol oxidation reaction owing to their special structures as well as compositions.

In attempts to investigate the potential luminescent sensing materials for sensitive detection of environmental pollutants, a new family of lanthanide wheel cluster organic frameworks (Ln-WCOFs) UJN-Ln4 has been constructed by employing one of the cycloalkane dicarboxylic acid derivatives. Adopting different conformations, the ligand links Ln 4 second building units (SBUs) and Ln 24 tertiary building units (TBUs) to form a unique wheel cluster layer-pillared 3D framework featuring the coexistence of hydrophobic nanosized channels and trigonal antiprism arrays with hydrophilic cagelike chambers. Apart from charming structures, isostructural UJN-Ln4 displays interesting porous, water-stable features. Systematic luminescence studies demonstrate that solvent water molecules can enhance the emission intensity of solid-state UJN-Eu4. Acting as a recyclable luminescent probe, water-stable luminescent UJN-Eu4 exhibits superior "turn-off" detection for Fe 3+ and Cu 2+ ions in aqueous solutions. Due to the nanosized hydrophobic channels, UJN-Eu4 also shows highly sensitive sensing of sodium dodecyl benzenesulfonate (SDBS) via luminescence "turn-on" respondence, representing the first example of quantitatively detecting SDBS in aqueous solutions by employing luminescent lanthanide frameworks as fluorescent sensors. The results also open up the exploration of novel luminescent Ln-WCOFs exhibiting unique applications in sensitive detecting of harmful pollutants in aquatic environments.

This work presents a method of generating electric current based on the defects of few-layer boron nitride nanosheets (BNNSs). The density functional theory calculations showed that the atomic charge of the B atom in acetone was more positive than in water. The electrostatic force microscopy measurements illustrated that the local electrical potential was 0.35 mV in acetone, while the potential signal was very difficult to capture when using water as the dispersant. This effect was further demonstrated by the performance of the acoustic energy-harvesting nanogenerator: the BNNSs were assembled into a film after being dispersed in acetone and then integrated into the generator device, generating average output current of ∼0.98 nA, which was much better than 0.2 nA, the average output current of another device with water as the dispersant. These results demonstrated that solvent effects made the as-prepared BNNSs carry net charges, which could be utilized to harvest acoustic energy and generate current.

In this article, AgVO3@AgBr@Ag nanobelt heterostructures were fabricated as an efficient visible-light photocatalyst through a hydrothermal process, an anion-exchange reaction, and a light-induced reduction. SEM and TEM characterization revealed that anion exchange followed by light-induced reduction is an efficient method to synthesize well-dispersed AgBr@Ag nanoparticles on the surface of AgVO3 nanobelts. The composite photocatalyst efficiently combines visible-light active AgBr and AgVO3 with the surface plasmon resonance (SPR) effect of Ag nanoparticles. The obtained catalyst displayed a high performance for removing organic dye in the range of visible light. This improved visible-light response likely originates from a synergistic effect of the different components. This work provides a versatile approach for accessing efficient, stable, and recyclable visible-light-driven plasmonic photocatalysts.

Silver oxide nanowire arrays (Ag2O NWAs) were first synthesized on a copper (Cu) rod by a simple and facile wet-chemistry approach without using any surfactants. The as-synthesized Ag2O NWA/Cu rod not only can be used as an integrated electrode (called a Ag2O NWA/CRIE) to detect hydrazine (HZ) but also can serve as the catalyst layer for a direct HZ fuel cell. The current density of HZ oxidation on Ag2O NWA (94.4 mA cm(-2)) is much bigger than that on a bare Cu rod (3.9 mA cm(-2)) at -0.6 V, and other Ag2O NWAs have the lowest onset potential (-0.85 V). This suggests that a Ag2O NWA integrated electrode has potential application in catalytic fields that contain the HZ fuel cell.

In this letter, Au-Cu(x)OS yolk-shell nanostructures with porous shell are prepared through a facile ion exchange route from Au@Cu(2)O core-shell nanostructures. The as-prepared yolk-shell nanostructures exhibit ultrasensitive enzyme-free detection of H(2)O(2) molecules with higher sensitivity (50.41 μA μM(-1)) and lower detection limit (0.01 μM) as well with excellent anti-interference capacity in comparison with both hollow Cu(x)OS nanospheres and Au nanoparticles. Therefore, the obtained Au-Cu(x)OS yolk-shell nanostructures have potential application in ultralow concentration enzyme-free H(2)O(2) detection for biomedicine diagnosis.