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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.

In this work, polymers of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-triphenylamine] with side chains containing: pyrene (C1), diphenyl (C2), naphthalene (C3), and isopropyl (C6) structures were synthesized via a Suzuki coupling reaction. The structures were verified using NMR and cyclic voltammetry measurements provide the HOMO and LUMO of the polymers. The polymer with pyrene (C1) and naphthalene (C3) produced photoluminescence in the green while the polymer with the side chain containing diphenyl (C2) and isopropyl (C6) produce dual emission peaks of blue-green photoluminescence (PL). In order to examine the electroluminescence properties of the polymers, the solutions were spin-coated onto patterned ITO anode, dried, and subsequently coated with an Al cathode layer to form pristine single layer polymer LEDs. The results are compared to a standard PFO sample. The electroluminescence spectra resemble the PL spectra for C1 and C3. The devices of C2, C3, and C6 exhibit voltage-dependent EL. An additional red emission peak was detected for C2 and C6, resulting in spectra with peaks at 435 nm, 490 nm, and 625 nm. The effects of the side chains on the spectral characteristics of the polymer are discussed.

Nanostructured diamond-like carbon (DLC) films instead of the ultrasmooth film were obtained by pulsed laser ablation of pyrolytic graphite. Deposition was performed at room temperature in vacuum with substrates placed at off-axis position. The configuration utilized high density plasma plume arriving at low effective angle for the formation of nanostructured DLC. Nanostructures with maximum size of 50 nm were deposited as compared to the ultrasmooth DLC films obtained in a conventional deposition. The Raman spectra of the films confirmed that the films were diamond-like/amorphous in nature. Although grown at an angle, ion energy of >35 eV was obtained at the off-axis position. This was proposed to be responsible for subplantation growth of sp3hybridized carbon. The condensation of energetic clusters and oblique angle deposition correspondingly gave rise to the formation of nanostructured DLC in this study.

Al-doped ZnO (AZO) thin films were deposited on p-Si (100) by pulsed laser deposition from a composite ceramic target (ZnO:Al2O3) by using 355 nm laser at different O2 background pressure and substrate temperature. Upon ablation at laser fluence of 2 Jcm−2, plasma plume consists of Zn neutrals and ions, Al neutrals and O neutral are formed. As the O2 background pressure increases from 3 Pa to 26 Pa, the energy of the plasma species are moderated. The results show that the ions density and velocity reduced significantly above 13 Pa. The velocity of the ions reduced from 14 kms−1 to 11 kms−1 at 13 Pa, while the ions energy reduced from 63 eV to 42 eV respectively. Below 13 Pa, crystalline and homogeneous AZO nanostructured films were formed. Above 13 Pa, the process results in low crystallinity films with higher porosity. The resistivity of the films also increases from 0.1 ohmcm to 24 ohmcm as the pressure increased. At fixed O2 background pressure of 3 Pa, the adatom mobility of atoms on the substrates is altered by substrate heating. The resistivity of the films decreased to 10–3 ohmcm when the substrates are heated to 100 °C–300 °C during deposition. The films with highest carrier density of 1020 cm−3 and carrier mobility of 13 cmV−1 s−1 are achieved at 200 °C.

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 2H5OH. 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.

This paper presents the results, analysis and discussions of parametric studies of diamond-like carbon (DLC) thin films by pulsed Nd:YAG laser deposition. Effects on the DLC properties and growth rate were investigated by varying the deposition parameters, namely the laser wavelength and fluence, substrate and temperature. For characterization, visible Raman spectroscopy, current-voltage measurement, optical interferometry, and optical absorption technique were employed. Comparisons were made with previous work by other workers who had also employed pulsed Nd:YAG lasers. The results also supported the subplantation mechanism for DLC formation.

Al-doped ZnO (AZO) thin films were deposited on p-Si (100) by pulsed laser deposition at room temperature to form AZO/p-Si heterojunctions. Crystalline films with different properties were obtained. The heterojunctions exhibit diode behavior in dark and responded to illumination of broadband visible (400 nm ~ 750 nm) and/or ultraviolet (368 nm) light in applied voltage range of only ±1 V. Visible photons are mostly absorbed in p-Si and UV photons were absorbed in AZO layer. However, the defects level within the bandgap of the AZO layer would also contribute to photocurrent under visible light illumination. The best photodetection was obtained for AZO with resistivity of 1 Ωcm and low defects density where the sample response to either UV or visible light by changing the biasing voltage from −1 V or +1 V.

A thorough study of MSnO 3 (M=Ca, Sr and Ba) compounds with respect to their synthesis, processing and microstructural characterization has been made. In order to establish a standard methodology with identical and beneficial microstructure and reproducible electrical characteristics, a novel preparative method called self-heat-sustained (SHS) reaction technique was employed. Evolution of microstructure which is intimately related to the envisaged properties in the ceramics, was closely and systematically followed in terms of wide temperature-soak time ( T-t ) profiles. The results showed that while a well-densified microstructure with small grain size (∼1 μm) and near zero porosity could be obtained by selecting a sintering schedule of 1350°C/ x h (48 h x ⩽ 60 h) for CaSnO 3 samples, very well sintered samples with relatively larger grains (3–5 μm) and minimal porosity could also be obtained by sintering at 1600°C for 2 h. Well-densified microstructure with small grain size and zero or near zero porosity could be obtained by a sintering schedule of 1350°C/ x h (12 h x ⩽ 24 h) in SrSnO 3 samples. Sintering of BaSnO 3 proved to be the most difficult. The BaSnO 3 samples could only be densified to the desired level by soaking the powder compacts for 2 h at 1600°C. The “sugar cube” features were replaced by the spherical grains (average size 1–2 μm).

Al-doped ZnO (AZO) films were deposited on glass and polycarbonate (PC) at room temperature by using pulsed Nd:YAG laser at 355 nm. AZO thin films were obtained for both substrates at laser fluences from 2 to 5 J/cm2 in O2 partial pressure of 2.1 Pa. The effects of laser fluence on the structural, electrical, and optical properties of the films were investigated. The films with lowest resistivity and highest transmittance have been obtained at 2 J/cm2. The resistivities were 2.29×10−3 Ω cm for AZO on glass and 1.49×10−3 Ω cm for AZO on PC. With increasing laser fluence, the deposited films have lower crystallinity, higher resistivity, and smaller optical bandgap.