Metal oxides for perovskite solar cells

The photovoltaic (PV) industry is attracting a lot of attention from researchers and industry alike. The conventional sources of energy pose a threat to the environment and are depleting at a rapid pace. Sooner or later, these sources need to be replaced with dependable and cleaner sources. The quest to develop solar cells with high efficiency and low cost is afoot. The first-generation solar cells achieved high efficiency but at a high manufacturing cost. The -generation solar cells had phenomenal success in balancing performance and cost but employed toxic materials. Third-generation solar cells such as perovskite solar cells have not only achieved high efficiency but have also overcome the shortcomings of previous generations. Perovskite solar cells (PSCs) consist of light-absorbing organic metal halides sandwiched between charge transport layers. The function of transport layers is to separate and transport the charges effectively. Metal oxides, due to their high chemical stability, easy processability and low cost, are most suitable as transport layers. Depending upon nature and band positions, the metal oxides can be used either as an electron or as a hole transport layer. Transport layers have a profound effect not only on the performance of the cell but also on the overall stability. In this chapter, we focus on the role of metal oxides in the fabrication and performance of PSCs. The different requirements and parameters essential for a metal oxide have been highlighted.