A team of researchers working at Oxford University has found a way to add cesium to perovskite solar cells to boost the performance of [silicon, while maintaining the efficiency benefits it offers. In their paper published in the journal Science, the team describes their process which included finding a way to overcome the problem of efficiency loss in such materials that normally come about due to a limited range of solar spectrum use.
As researchers around the world continue to look for the next-generation material to use for solar power collection to increase efficiency, others continue to seek ways to improve the standard now in use: silicon.
Ref: A mixed-cation lead mixed-halide perovskite absorber for tandem solar cells. Science (8 January 2016) | DOI: 10.1126/science.aad5845
Metal halide perovskite photovoltaic cells could potentially boost the efficiency of commercial silicon photovoltaic modules from ∼20 toward 30% when used in tandem architectures. An optimum perovskite cell optical band gap of ~1.75 electron volts (eV) can be achieved by varying halide composition, but to date, such materials have had poor photostability and thermal stability. Here we present a highly crystalline and compositionally photostable material, [HC(NH2)2]0.83Cs0.17Pb(I0.6Br0.4)3, with an optical band gap of ~1.74 eV, and we fabricated perovskite cells that reached open-circuit voltages of 1.2 volts and power conversion efficiency of over 17% on small areas and 14.7% on 0.715 cm2 cells. By combining these perovskite cells with a 19%-efficient silicon cell, we demonstrated the feasibility of achieving >25%-efficient four-terminal tandem cells.