Research following Pb Perovskite Solar Cells

Certified efficiency of Pb perovskite solar cells with mixed cations is reported to be 19.6% (1 cm2). One of the recent research interests is on enhancing the solar cell efficiency further. Band gap of the present Pb perovskite is about 1.55 eV. Supposing that Voc loss is 0.4 eV, the best efficiency is obtained by using perovskite with about 1.4 eV band gap. One of the candidates for the narrow band gap perovskite material is SnPb mixed metal perovskite. In this paper, the relationship between Voc losses and hetero-interface structures is discussed in detail, leading to the conclusion that hetero-interface structures give serious effects on the solar cell efficiency. It is reported that the efficiency was enhanced from about 5% to 16% after optimization of the hetero-interface structure. In addition, research trend on Pb free perovskite solar cells consisting of Sn or Bi, which is another recent research interest, is also reviewed.