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A simple, low-cost and sensitive UV sensor based on electrospun composite fibers was fabricated. Three different types of (PVA/ZnO) composites were used to fabricate the device. The solution-cast film of PVA and ZnO shows lower photocurrent than the other two fiber based devices. A comparative photoresponse study has revealed the high sensitiveness of the in situ derived composite fibers of PVA and ZnO under UV illumination thus making them highly suitable for the fabrication of UV detector. We believe that the coupled effect arising from the presence of PVA and uniform distribution of ZnO are responsible for the sensitivity of UV sensor. Thus we conclude that the response of UV sensor is highly dependent on the morphology of the composites and the preparation method. � 2012 Elsevier B.V.

One dimensional nanofibers of organic and inorganic materials have been used in filters, optoelectronic devices, sensors etc. It is difficult to obtain ultra fine fibers of inorganic materials having lengths in the order of millimeter as they tend to break during formation due to thermal and other mechanical stresses. In this study, we have investigated the mechanism to prevent the defect formation and the breaking ZnO nanofibers by using optimized heat flow rates. ZnO nanofibers were obtained by heat treating the PVA composites fibers formed by electrospinning. The morphology and structural characteristic of prepared samples were investigated by Scanning electron microscopy and X-ray diffraction. It was found that the morphology of the composite and annealed nanofibers could be influenced by the concentration of the polymer content and heat flow rate during thermal treatment respectively. A lower concentration favors the formation of defects along the fiber and the number of defects reduces when the concentration is increased. The reasons for the formation of defects and their reduction, and the observed structural changes of ZnO nanofibers during heat treatment are also discussed. � 2010 Elsevier B.V. All rights reserved.

Fabrication of ultraviolet light emitting devices using ZnO nanostructures is still difficult due to the high cost synthesis for high quality ZnO. It is important to suppress the visible emission. In this paper, we report the effective low cost in-situ preparation of high quality monodispersed and non-agglomerate ZnO nanoparticles in nanofibrous PVA matrix derived from electrospinning method. The final product was investigated by SEM, EDAX, XRD, FTIR, TEM, and SAED. The XRD analysis proved the successful preparation of ZnO with wurtzite hexagonal phase. FTIR spectroscopic measurements showed the interaction between ZnO and PVA. The purity of the sample was studied using PL. The result showed that the obtained sample exhibits intense ultraviolet emissions at 369 nm while the absence of deep level emission confirms the high quality sample. PVA matrix and electrospinning method are found to have a vital role to the preparation of defect free ZnO. Experimental results have proven that the prepared ZnO by this method have excellent optical quality. � 2011 Elsevier B.V. All Rights Reserved.

Here we report an approach to fabricate flexible polymer self standing films embedded with continuous aligned microtubes/microchannels via electrospinning. The scheme is to wash the electrospun fibers selectively to form either microtubes/microchannels. Optical microscope (OM) and Scanning electron microscope images are evident for the well aligned microtubes and microchannels respectively with a diameter of ?8 ?m and a length of ?4 cm. Meniscus of tetrahydrofuran in the microtubes can be observed explicitly in the OM images. Mutually perpendicular microtubes are also fabricated on a polymer film. Angular distribution of aligned microstructures indicates the standard deviation is not more than 1�. These tubes/channels can be potential for tissue engineering as they could provide a directional template for the growth when a biodegradable polymer such as Poly(vinylalcohol) is used. � 2011 Elsevier B.V. All rights reserved.