No abstract

In this work, flexible composite membranes of nanoparticles (CuO, ZnO, or both), poly(vinyl alcohol) (PVA), and glycerol (GL) plasticizer are fabricated of for X-ray detector applications. The nanoparticles are synthesized by a modified solvothermal technique and introduced to PVA + GL solution to fabricate the membranes. The mean sizes of nanoparticles are 10 Ç 4 nm and 8 Ç 3 nm, for CuO and ZnO in order. The composition of nanoparticles and membranes are investigated by energy dispersive x-ray spectroscopy and x-ray spectroscopy. Increasing nanoparticle concentration within the membranes causes their glass transition temperature to shift to low temperatures and enhances their thermal resistance. Fourier-transform infrared spectroscopy demonstrates the formation of hydrogen bonds between nanoparticles and PVA that are generated by the intermolecular and intramolecular hydrogen bonds. Impedance spectroscopy characterization reveals that the membranes hold negative temperature coefficient of the resistance. The activation energy decreases with increasing nanoparticle concentration. The composite membranes exhibit a decent response to x-ray that is proportional to its energy. The best x-ray response is for the membranes with both CuO and ZnO nanoparticles, because of their different bandgaps that cause a wide range of excitation energy to be involved. The fabricated membranes have numerous advantages such as their semiconductor features, flexibility, and feasibility of fabrication on a large scale with reasonable cost.