Alignment of 1D assemblies of a wide variety of nanoparticles (e.g., metal, metal oxide, semiconductor quantum dots, or organic microspheres) in one direction upon diverse substrates (including industrial silicon wafers and transparent glass plates) by a general strategy is demonstrated. This sandwich method provides an efficient way of rapidly and precisely assembling nanoparticles on a large scale (up to 10 cm × 10 cm) for device applications.
In this work, we adopted a fully computer-guided strategy in discovering an efficient pH-switchable organic photocatalyst (OPC), unprecedentedly turning colorless at pH 5 and recovering strong visiblelight absorption and photoactivity at pH 7. This is the first example of an OPC design fully guided by comprehensive density functional theory (DFT) studies covering electrostatic, electrochemical, and photophysical predictions. Characterization of the designed OPC after synthesis confirmed the computational predictions. We applied this OPC to mediate an aqueous photoinduced electron/energy transfer-reversible addition−fragmentation chain transfer (PET-RAFT) polymerization under green LED light (nominal emission wavelength: 530 nm, 5 mW/ cm 2 ). We demonstrated that the polymerization can be reversibly ceased by a slight change of pH (pH ≤ 5.0) or in the absence of light. Furthermore, we demonstrated that the polymerization rate could be significantly retarded by bubbling carbon dioxide into the reaction solution under visible light. Conversely, the rate could be fully recovered via exposure to nitrogen gas. This is the first example of a pH and light dual-gated polymerization system with complete and reversible inhibition.
Two-dimensional (2D) N-graphdiyne (N-GDY) nanosheets containing different number of N were synthesized by polymerization of triazine, pyrazine, and pyridine-based monomers at liquid/liquid interface. The configurations and nanostructures of N-GDY were well-characterized. The wettability changed to more hydrophilic as the N contents increased. The collected N-GDY was further employed as metal-free photocatalyst for NADH regeneration. The catalytic performance was related with the N content in the graphdiyne. The N3-GDY demonstrated the best activity. This strategy provided a new promising platform of designing unique 2D N-GDY with tunable performance in biorelated catalysis.
We explored the interfacial synthesis of 2D N-graphdiyne films at the gas/liquid and liquid/liquid interfaces. Triazine- or pyrazine-based monomers containing ethynyl group were polymerized through the Glaser coupling reactions at interfaces. Several layered, highly ordered and conjugated 2D N-graphdiyne were obtained. Their structures were characterized by TEM, SEM, AFM, XPS, and Raman spectra. Thin films with minimum thickness of 4 nm could be prepared.
As a new member of carbon allotropes, graphdiyne is a promising material with excellent electronic performance and high elasticity, indicating the possibility of graphdiyne to serve as the building blocks in flexible electronics. However, precise positioning/patterning of graphdiyne is still a challenge for the realization of large-area and flexible organic electronic devices and circuits. Here, the direct in situ synthesis of patterning graphdiyne stripe arrays dominated by the superlyophilic grooved templates is reported, whereas the superlyophilicity of grooved templates plays a key role in allowing continuous mass transport of raw reactants into the microscale spacing. After the completion of cross-coupling reaction procedure, precisely patterned graphdiyne stripes can be generated accordingly. The size of graphdiyne stripe arrays is depending on the silicon substrate size (1 cm × 1.5 cm), and the layer thickness can be manipulated from just several nanometers to hundreds of nanometers by varying the primary concentration of hexaethynylbenzene monomers. As a proof-of-principle demonstration, a stretchable sensor based on the graphdiyne stripe arrays is performed to monitor the human finger motion. It is expected that this wettability-facilitated strategy will provide new insights into the controlled synthesis of graphdiyne toward promising flexible electronics and other optoelectronic applications.
The charge transfer from the donor to the acceptor units results in a CT complex with excellent near-infrared photothermal conversion efficiency, which acted as an excellent photothermal material in seawater desalination application.
Large‐scale patterning of high‐quality organic semiconductors is crucial for the fabrication of optoelectronic devices with high efficiency and low cost. Yet, owing to the uncontrollable dewetting dynamics of organic liquid in conventional solution patterning techniques, large defect density of organic architectures is inevitable, which is detrimental to the device performance. To address this challenge, herein a capillary‐bridge‐mediated assembly technique is developed for regulating the dewetting process, yielding large‐scale 1D microstructure ordered arrays. The 1D arrays organic photodetectors exhibit a high optoelectronic performance of light on/off ratio exceeding 100, responsivity of 3.24 A W−1, detectivity of 3.20 × 1011 Jones and fast response speed, showing a great improvement compared with spin‐coated membrane devices. In addition, the significant enhancement of the device photodetection under the electronic field modulation is investigated by applying a back‐gate voltage and explained with the photocurrent predominating in the OFF state and the neglected thermocurrent and tunneling current promoting in the ON state of the phototransistor devices. The research offers a new insight for the facile fabrication of large‐scale integrated photodetectors and other organic devices based on patterned conjugated polymers.
Single crystalline arrays with an area of 1 × 2 cm2and high mobilities could be obtained through the superhydrophobic micropillar flow-coating (SMFC) technique.
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