Triboelectric nanogenerators (TENGs) have attracted many researchers’ attention with their remarkable potential despite the fact that the practical implementation requires further improvement in their electric performance. In this work, a novel graphene phase two-dimension material, graphitic carbon nitride (g-C3N4), was employed for the development of a TENG material with enhanced features. An electrospun nanofibrous PA66 membrane doped with g-C3N4 was fabricated as a multifunctional TENG for harvesting different kinds of mechanical energy and detecting human motions. By utilizing the innovative 2D material in PA66 solution for electrospinning, the as-made TENG showed a two times enhancement in electrical performance as compared to the control device, and also had the advantages of lightweight, softness, high porosity, and rugged interface properties. The assembled TENG with 4 cm2 could light up 40 light-emitting diodes by gentle hand clapping and power electronic watches or calculators with charging capacitors. At a given impact force of 40 N and 3 Hz, the as-made TENG can generate an open-circuit voltage of 80 V, short current of ±3 µA, charge transfer of 50 nC, and a maximum power density of 45 mW/m2 at a load resistance of 500 MΩ. The UV light sensitivity of TENG was also improved via g-C3N4 doping, showing that charge transfer is very sensitive with a two times enhancement with dopant. For the demonstration of applications, the g-C3N4 doped TENG was fabricated into an energy flag to scavenge wind energy and sensor devices for detecting human motions.
Symmetrical azobenzene derivatives with two catechol groups, 1d–4d, were synthesized as kinds of novel compounds, and the structures were confirmed using mass spectrometry and nuclear magnetic resonance spectroscopy. These compounds could attain photostationary state rapidly in solution upon UV irradiation, and their photochromism had good reversibility. Substituents and their positions on azobenzene chromophore had obvious influence on the maximum absorption and photochromic performances of these as-synthesized compounds. Electron-donating group on
ortho
positions could contribute to the redshift π–π* band. The sulfonamide group that is bonded to dopamine molecules and azobenzene rings caused a negligible n–π* transition of
cis
isomer, resulting in photobleaching upon UV irradiation. Among the four compounds, 4d had the strongest electron-donating
ortho
-methoxy substituents and lower planarity; thus its absorption could decrease more significantly upon UV irradiation of the same intensity, and its
cis
-to-
trans
conversion could be up to 63%. Furthermore, owing to the presence of catechol groups, 4d showed an effective affinity and adhesion to substrate, and on the surface of substrate, a weak colour change could be observed upon UV irradiation, but the reversibility was poorer than that in solution.
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