Titanium dioxide nanostructures for photoelectrochemical applications

Organic Photovoltaics: Materials, Device Physics, and Manufacturing Technologies

Electrospinning is a powerful technique to produce nanofibers of tunable diameter and morphology for medicine and biotechnological applications. By doping electrospun nanofibers with inorganic and organic compounds, new functionalities can be provided for technological applications. Herein, we report a study on the morphology and optical properties of electrospun nanofibers based on the conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and poly(methylmethacrylate) (PMMA). Initially, we investigate the influence of the solvent, surfactant, and the polymer concentration on electrospinning of PMMA. After determining the best conditions, 0.1% MEH-PPV was added to obtain fluorescent nanofibers. The optical characterizations display the successful impregnation of MEH-PPV into the PMMA fibers without phase separation and the preservation of fluorescent property after fiber electrospinning. The obtained results show the ability of the electrospinning approach to obtain fluorescent PMMA/MEH-PPV nanofibers with potential for optical devices applications. VC 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1388–1394

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Fluorescent PMMA/MEH‐PPV electrospun nanofibers: Investigation of morphology, solvent, and surfactant effect

Herein, we explore the effect of graphene concentration on performance of poly [2-methoxy-5-2-ethylhexoxy-p-phenylene vinylene] (MEH:PPV)/graphene nanocomposite based devices. The surface morphology of the nanocomposites analyzed through emission scanning electron microscopy suggest that increase in graphene concentration results in the formation of aggregation. Optical and structural properties of the nanocomposites examined through UV–Vis absorption and Raman spectra revealed that the addition of graphene has no affect on the conjugation length and structure of the MEH:PPV. The electrical characteristics of devices have been investigated by I–V measurement under dark and illumination at room temperature. The devices show increase in the current value and reduction on turn-on voltage with increase in the graphene concentration up to 5 wt%. However, increase in graphene concentration above 5 wt% leads to the performance degradation of the devices. Moreover, charge transport mechanisms of the devices have been explained through Ohmic behavior at lower voltages and trap charge limited conduction at higher voltages.

Effect of graphene concentration on performance of MEH:PPV/graphene nanocomposite based devices

Effects of annealing temperature and cooling rate on photo-electrochemical performance of pristine polycrystalline metal-chalcogenide film electrodes

Improvement of photoelectrochemical and optical characteristics of MEH-PPV using titanium dioxide nanoparticles

Effect of the annealing oxidation time of electrodeposited lead (Pb) on the phase formation of lead oxide (PbO) films is reported. The phase structure, optical properties, size and morphology of the films were investigated by scanning electron microscopy, X-ray diffraction and UV-vis spectroscopy. The relationship between structur and photoelectrochemical properties was investigated. Thin films of PbO produced via air annealing of electrodeposited lead consist of a mixture of two phases, orthorhombic (o -PbO) and tetragonal (t -PbO), that determine the material properties and effectiveness as absorber layer in a photoelectrochemical device. The proportion of tetragonal t -PbO increases for longer heat treatments. After 40 h, the sample consists mainly of tetragonal t -PbO. The p-type semiconducting behavior of lead oxide was studied by photocurrent measurements. Different heat treatments yield variations in the ratio of tetragonal to orthorhombic lead oxide that effect on device performances, where devices with a higher content of tetragonal t -PbO show higher photocurrent than with the orthorhombic phase.

Annealing effect on the optical and photoelectrochemical properties of lead oxide

In this work, MEH-PPV+Bis-PCBM+ZnO composite material was prepared by incorporation of Zinc oxide nonoparticles (ZnO) into poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) and Bis-(PCBM) polymers matrix and deposited by spin coating on glass and indium thin oxide (ITO) substrates. The effect of inserting a ZnO nanoparticles interlayer in the MEH-PPV+Bis-PCBM polymer heterojunction device on the electrochemical and optical characteristics of the device has been studied. The absorbance of various MEH-PPV+BisPCBM composites incorporating of ZnO nanoparticles shows that addition of ZnO improves absorption of the composites. As a result, the composite has slightly broader absorption. The study showed that the presence of inorganic semiconductor nonoparticles (ZnO) in polymer film improves the optical and the photovoltaic properties of MEH-PPV+Bis-PCBM, and was designed to explore new approaches to improve lightcollection efficiency in polymer photovoltaic.

Wided Zerguine

Papers

Improvement of photoelectrochemical and optical characteristics of MEH-PPV using titanium dioxide nanoparticles

Annealing effect on the optical and photoelectrochemical properties of lead oxide

Improvement of optical and photoelectrochemical properties of conducting polymer by incorporation of ZnO nanoparticles