**Abstract**

Global energy shortage will be one of the most critical challenges in the next 50 years. Currently, over 80% of energy consumed is produced from fossil fuels, which is directly linked to global warming and environmental pollution issues. Environment-friendly renewable energy is rapidly gaining importance for the existence of human civilization. A leading source of renewable energy is the solar energy, which is inexhaustible and abundantly available. Solar cells that convert solar energy directly into electricity are drawing considerable attention as a potential turnkey solution to address these challenges. Several approaches have been made in this respect, including the development of better materials and the designs of new solar cell configuration and architecture. Among the innovative materials with potential application in emerging 3G solar cells, graphene and its derivatives such as GO, rGO and G/nanocomposite have been widely explored as transparent conducting electrodes, electron donor or acceptor materials and counter electrodes (CE). In this chapter, the use of graphene nanocomposites has been explored as an electrode material in DSSCs and PSCs. Recently, graphene/metal oxide nanocomposites have been widely used in DSSCs and PSCs and played a significant role in increasing charge transport, reducing charge recombination and thus enhancing the performance of solar cell.

**Keywords:** graphene, nanocomposite, metal oxide, photoanode, energy, DSSCs, PSCs
