Solar-Energy Conversion in TiO2/CuInS2 Nanocomposites

• Published in: Advanced functional materials 2005-01, Vol.15 (1), p.95-100
• Main Authors: Nanu, M., Schoonman, J., Goossens, A.
• Format: Article
• Language: English
• Subjects: Composite materials; Heterojunction; inorganic; Nanostructured materials; Solar cells; Solar cells, inorganic; Titania
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200400150

The search for low‐cost thin‐film solar cells, to replace silicon multi‐crystalline cells in due course, calls for new combinations of materials 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 CuInS2 inside the pores of nanostructured TiO2. In this way it is possible to obtain a nanometer‐scale interpenetrating network between n‐type TiO2 and p‐type CuInS2. 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 a maximum monochromatic incident photon‐to‐current conversion efficiency of 80 % and have an energy‐conversion efficiency of 4 %. The three‐dimensional‐solar‐cell concept is explored using a new approach. A nanocomposite consisting of a wide‐bandgap n‐type semiconducting oxide (nanocrystalline TiO2) and a p‐type visible‐light‐sensitive semiconductor (CuInS2), mixed on a nanometer scale (see Figure), is used as the active material.