Solar-energy conversion in TiO2/CuInS2 nanocomposites

The search for low-cost thin-film solar cells, to replace silicon multi-crystalline cells in due course, calls for new combinations of material and new cell configurations. Here we report on a new approach, based on semiconductor nanocomposites, towards what we refer to as the three-dimensional (3D) solar-cell concept. Atomic layer chemical vapor deposition is employed for infiltration of CulnS(2) inside the pores of nanostructured TiO2. in this way it is possible to obtain a nanometer scale interpretating network between n-type TiO2 and p-type CulnS(2). X-ray diffraction, Raman spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, transmission electron microscopy, and current-voltage measurements are used to characterize the nanostructured devices. The 3D solar cells obtained show photovoltaic activity with maximum monochromatic incident photon-to-current conversion efficiency of 80% and have an energy-conversion efficiency of 4%.