Synthesis and Luminescence Characterization of Downconversion and Downshifting Phosphor for Efficiency Enhancement of Solar Cells: Perspectives and Challenges

Currently, the world is facing an energy crisis. One of the techniques to fulfill the energy demand is to increase the utilization of solar energy. For harvesting solar energy in large amounts, it is essential to develop efficient solar cells. Notably, solar cells (photovoltaic cells) produce electricity from solar energy. The biggest hurdles, however, are the capability and reliability of solar cells. Poor energy density and the spectrum in the bandgap of semiconductor phosphors do not match the energy allocation of the photons in solar spectra lines. These issues and cell efficacy must be addressed before photovoltaic cells can be developed as a viable source of electrical power. The amount of energy generated per unit area depends linearly on cell efficiency. Hence, it makes sense to increase the efficiency rather than enhancing the space for solar cell installation. One well-known method for converting a high-energy photon into two or more lower-energy photons is "downconversion", which makes use of the wide solar spectrum required for solar cells. The design maximizes the use of the entire sunlight spectrum, improving the efficiency of various solar cell types. This review article surveys how spectrum converters, especially lanthanide-based downconverters and downshifters will be developed. This review focuses on the current materials and methods used to enable the downconversion and downshifting processes in solar cells and some of the challenges in developing solar cells.