These days, solar cells have attracted considerable attentions because they are environment-friendly sources of electric power. The present review is focused on composites and materials that are used in the solar cells field, including Si-based solar cells, dye-Sensitized solar cells (DSSC), thin film solar cells, Quantum dot solar cells (QDSC) and Perovskite solar cells (PSC). TiO 2 based nanocomposites, which are widely applicable in the solar cells are also reviewed.