Engineering of TiO2 or ZnO—Graphene Oxide Nanoheterojunctions for Hybrid Solar Cells Devices

Abstract

It is currently of huge importance to find alternatives to fossil fuels to produce clean energy and to ensure the energy demands of modern society. In the present work, two types of hybrid solar cell devices were developed and characterized. The photoactive layers of the hybrid heterojunctions comprise poly (allylamine chloride) (PAH) and graphene oxide (GO) and TiO2 or ZnO films, which were deposited using the layer-by-layer technique and DC-reactive magnetron sputtering, respectively, onto fluorine-doped tin oxide (FTO)-coated glass substrates. Scanning electron microscopy evidenced a homogeneous inorganic layer, the surface morphology of which was dependent on the number of organic bilayers. The electrical characterization pointed out that FTO/(PAH/GO)50/TiO2/Al, FTO/(PAH/GO)30/ZnO/Al, and FTO/(PAH/GO)50/ZnO/Al architectures were the only ones to exhibit a diode behavior, and the last one experienced a decrease in current in a low-humidity environment. The (PAH/GO)20 impedance spectroscopy study further revealed the typical impedance of a parallel RC circuit for a dry environment, whereas in a humid environment, it approached the impedance of a series of three parallel RC circuits, indicating that water and oxygen contribute to other conduction processes. Finally, the achieved devices should be encapsulated to work successfully as solar cells.

Graphene Oxide Layer-by-Layer Films for Sensors and Devices

“…This symmetry may also mean that there is not much difference between the working functions of the electrodes used. These results are in accordance with the recent achievements on hybrid solar-cells based in both PAH/GO and TiO 2 or ZnO films, in which the developed architectures exhibit a diode like behavior and a decrease in current in a low-humidity environment [41].…”

Graphene and Graphene Based Nanocomposites for Bio‐Medical and Bio‐safety Applications

“…From these, graphene oxide and its derived materials have proved benefit in biological applications, and in recent years, the number of studies looking at graphene and its derivatives as a reinforcing phase in composite coatings has been growing quickly. [136] Apart from these applications, Graphene oxide and its based nanocomposites also have application in biomedical devices like sensor device, nucleic acid sensor device, immune sensor device, cell sensor device, imaging devices, etc.. [164,165,166]…”

“…Apart from these applications, Graphene oxide and its based nanocomposites also have application in biomedical devices like sensor device, nucleic acid sensor device, immune sensor device, cell sensor device, imaging devices, etc. [164,165,166] …”