Hong-Dan Peng

Facile microwave-assisted synthesis of Klockmannite CuSe nanosheets and their exceptional electrical properties.

Klockmannite copper selenide nanosheets (CuSe NSs) are synthesized by a facile microwave-assisted method and fully characterized. The nanosheets have smooth surface and hexagonal shape. The lateral size is 200–500 nm × 400–800 nm and the thickness is 55 ± 20 nm. The current-voltage characteristics of CuSe NS films show unique Ohmic and high-conducting behaviors, comparable to the thermally-deposited gold electrode. The high electrical conductivity of CuSe NSs implies their promising applications in printed electronics and nanodevices. Moreover, the local electrical variation is observed, for the first time, within an individual CuSe NS at low bias voltages (0.1 ~ 3 V) by conductive atomic force microscopy (C-AFM). This is ascribed to the quantum size effect of NS and the presence of Schottky barrier. In addition, the influence of the molar ratio of Cu2+/SeO2, reaction temperature, and reaction time on the growth of CuSe NSs is explored. The template effect of oleylamine and the intrinsic crystal nature of CuSe NS are proposed to account for the growth of hexagonal CuSe NSs.

Precise growth of low-dimensional pyrene·perylene·TCNQ co-crystals and structure–property related optoelectronic properties

A phase-transformation method has been developed for the precise growth of charge-transfer (CT) co-crystals with varied stoichiometries. Perylene·TCNQ (P1T1) microrods, pyrene·perylene·TCNQ (PyPeT) microrods and (perylene)3·TCNQ (P3T1) microsheets were successfully constructed. The phase transformation can not only happen from P1T1 or P3T to PyPeT, but also from P3T1 to P1T1, which can be controlled by changing the solute concentration. Due to the additional pyrene in PyPeT compared to P1T1, devices based on PyPeT microrods show slightly lower electron mobility and much larger positive threshold than P1T1 microrods. In addition, both of them can be used as phototransistors with a maximum Ion/Ioff ratio of ca. 1000.

Wearable Wide-Range Strain Sensors Based on Ionic Liquids and Monitoring of Human Activities

Wearable sensors for detection of human activities have encouraged the development of highly elastic sensors. In particular, to capture subtle and large-scale body motion, stretchable and wide-range strain sensors are highly desired, but still a challenge. Herein, a highly stretchable and transparent stain sensor based on ionic liquids and elastic polymer has been developed. The as-obtained sensor exhibits impressive stretchability with wide-range strain (from 0.1% to 400%), good bending properties and high sensitivity, whose gauge factor can reach 7.9. Importantly, the sensors show excellent biological compatibility and succeed in monitoring the diverse human activities ranging from the complex large-scale multidimensional motions to subtle signals, including wrist, finger and elbow joint bending, finger touch, breath, speech, swallow behavior and pulse wave.

Flexible Highly Sensitive Pressure Sensor Based on Ionic Liquid Gel Film

Flexible, semitransparent ionic liquid gel (ionogels) film was first fabricated by in situ polymerization. The optimized ionogels exhibited excellent mechanical properties, high conductivity, and force sensing characteristics. The multifunctional sensor based on the ionogel film was constructed and provided the high sensitivity of 15.4 kPa–1 and wide detection range sensing from 5 Pa to 5 kPa. Moreover, the aforementioned sensor demonstrated excellent mechanical stability against repeated external deformations (for 3000 cycles under 90° bending). Importantly, the sensor showed advantages in detection of environmental changes to the external stimulus of subtle signals, including a rubber blower blowing the sensor, gently touching, torsion, and bending.

Shape-controlled synthesis of platinum octaethylporphyrin crystalline aggregates modulated by versatile ionic liquids

This work presents a facile approach toward the synthesis of platinum octaethylporphyrin crystalline aggregates with wires, leaves, plates, and four-leaf clover like architectures by exploitation of intriguing ionic liquid-mediated solution self-assembly. Moreover, the well-defined microwires exhibit highly reproducible and sensitive photo-response characteristics.

Solvent-induced self-assembly synthesis of ultralong single crystalline organic NiOEP nanowires with high photoconductivity

We develop a facile approach for the one-step growth of ultralong and high-quality NiOEP nanowires in a large area, through a solvent-induced self-assembly method without using any structure directing agents. The size of the nanowires can be controlled by changing the composites of solvent mixtures. Being assembled in visible-light sensors, these nanowires exhibit a fast, reversible, and stable response. The highest Ion/Ioff ratio and photoresponsivity of photodiodes could reach 681 and 10.1 mA W−1, respectively, which could be attributed to the perfect single crystal quality, large surface to volume ratio, and fewer recombination barriers within the nanostructures. The facile fabrication and good photoresponse make NiOEP nanowires promising in optoelectronic applications.

Efficient non-halogenated solvent for the template-free solution synthesis of ultralong copper octaethylporphyrin nanowire networks with strong photoswitching properties

Rationally solution-processed organic electronics are expected to pave the way for low-cost and large-area devices with new and exciting applications. In this study, a non-halogenated solvent was employed for the first time for the one-step and scalable synthesis of extremely high aspect ratio organic semiconducting nanowires of copper octaethylporphyrin (CuOEP) using a cast assembly method under a solvent atmosphere. Remarkably, these single crystalline nanowires exhibited excellent photoswitching effects with reliable reproducibility and superior stability, indicating their potential for application in high-performance optoelectronic devices.

Facile fabrication and excellent electrical conductivity of ultralong nanobelt film of butoxy-substituted copper phthalocyanines

Well-defined single-crystalline nanobelts of butoxy-substituted copper phthalocyanine (CuPcOC4) have been rapidly prepared by a facile and reliable non-solvent nucleation method without any template. Remarkably, the nanobelt film exhibited an excellent electrical conductivity of up to 5.2 S m−1, which is one of the highest values reported for organic semiconducting materials.