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Carbon nanomaterials exhibit novel characteristics including enhanced thermal, electrical, mechanical, and biological properties. Nanodiamonds; first discovered in meteorites are found to be biocompatible, non-toxic and have distinct optical properties. Here we show that nanodiamonds with the size of <5 nm are formed directly from ethanol via 1025 nm femtosecond laser irradiation. The absorption of laser energy by ethanol increased non-linearly above 100 μJ accompanied by a white light continuum arises from fs laser filamentation. At laser energy higher than 300 μJ, emission spectra of C, O and H in the plasma were detected, indicating the dissociation of C2H5OH. Nucleation of the carbon species in the confined plasma within the laser filaments leads to the formation of nanodiamonds. The energy dependence and the roles of the nonlinear phenomenon to the formation of homogeneous nanodiamonds are discussed. This work brings new possibility for bottom-up nanomaterials synthesis based on nano and ultrafast laser physics.

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Low-temperature growth of indium tin oxide (ITO) nanowires (NWs) was obtained on catalyst-free amorphous glass substrates at 250 °C by Nd:YAG pulsed-laser deposition. These ITO NWs have branching morphology as grown in Ar ambient. As suggested by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), our ITO NWs have the tendency to grow vertically outward from the substrate surface, with the (400) plane parallel to the longitudinal axis of the nanowires. These NWs are low in electrical resistivity (1.6×10⁻⁴ Ω cm) and high in visible transmittance (~90–96%), and were tested as the electrode for organic light emitting devices (OLEDs). An enhanced current density of ~30 mA cm⁻² was detected at bias voltages of ~19–21 V with uniform and bright emission. We found that the Hall mobility of these NWs is 2.2–2.7 times higher than that of ITO film, which can be explained by the reduction of Coulomb scattering loss. These results suggested that ITO nanowires are promising for applications in optoelectronic devices including OLED, touch screen displays, and photovoltaic solar cells.

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In recent years, several strategies have been proposed and demonstrated to enhance the efficiency of organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs). In both types of devices, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is commonly used to enhance hole injection. The layer is further designed by incorporating metallic-based, carbon-based, organic, inorganic, and hybrid nanoparticles with the aim of improving the performance and hence the efficiency through the improvement of light out-coupling in OLEDs and enhancement in light absorption generation of hole-charge carriers in OPVs. This review elucidates the use of different types of nanoparticles that are doped into PEDOT:PSS and their effects on OLEDs or OPVs. The effects include surface plasmon resonance (SPR), scattering, better charge transport, improvement in surface morphology and electrical properties of PEDOT:PSS. Promising results have been obtained and can potentially lead to low cost, large-area manufacturing process.

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Photoelectron spectra of both liquid and gas phase aromatic molecules are reported.