Manuel Apollo
Solar photovoltaics from II-VI nanowire materials
The University of Liverpool
There is a global drive to increasing the efficiency, performance and cost effectiveness of renewable energy sources including the photovoltaic (PV) devices. For solar PV, it is possible that nanostructures may be used to create new kinds of devices with enhanced optical performance over existing structures. It is the aim of our project to explore these opportunities, with II-VI semiconductors, and in particular cadmium telluride (CdTe) being the material under investigation. In Fig.1 Typical CdTe solar cells are shown.
Fig. 1 Schematic diagrams of typical CdTe solar cells adopting the “superstrate” (left) and “substrate” (right) configuration.
The project will start by developing new methods to create nanowires of CdTe which is itself a commercially important solar absorber material, in particular exploring the possibility to grow the nanowires in the template assisted method, using aluminum oxide porous membranes (shown in Fig. 2), titanium oxide nanotubes and nanoimprints.
Fig. 2 On the left an ideal structure of porous aluminum oxide; on the right its cross sectional view.
Once obtained the templates, different techniques relating the nanostructures growth (sublimation, VLS, CSS, Sputtering, spin coating) will be explored. The nanostructures so obtained will be characterized via XRD, SEM, UV-UVS-IR. It is the aim to then fabricate and test working solar cell devices from the nanowire materials via impedance analysis, current-voltage, capacitance voltage, PV performance (Air Mass 1.5).
