Solar cells convert sunlight into electricity directly. It is a reliable, non-toxic and pollution free source of electricity. Since 19th century researchers have been trying to investigate different materials for solar cell devices. Commercially, Si based solar are predominate in this field, however, with passage of time different materials have been reported. Solar cell techniques are based on three different generations. 1st generation is based on Si and 2nd generation includes thin-films of CuInGaSe, GaAs, CdTe and GaInP etc. whereas 3rd generation is based on organic, hybrid perovskites, quantum dot (QD)-sensitizers & dye-sensitizers solar cells. Among all these, the 3rd generation solar cells are the most efficient and more cost effective than 1nd and 2nd generation solar cells. The 2nd generation is less costly but also less efficient compared to 1st generation. 3rd generation faces degradation of the photovoltaic materials which is a major problem. In this chapter different reported materials since 19th century for solar cells are mentioned. The past and present scenarios of solar cells are discussed comprehensively. It is observed that Si-based and multijunction solar cells dominate the market. Although, theoretically it is reported that hybrid perovskites and quantum dot materials for solar cell are the most efficient materials for photovoltaic PV devices. In spite of the high efficiency the stability of organic, hybrid perovskites, QD-sensitizers &dye-sensitizer materials is a big challenge.
III–V Multijunction Solar Cell Integration with Silicon: Present Status, Challenges and Future Outlook