摘要：Intrinsic polarization of ferroelectrics (FE) helps separate photon-generated charge carriers thus enhances photovoltaic effects. However, traditional FE with transition-metal cations ( M ) of d 0 electron in M O6 network typically has a band gap ( E g) exceeding 3.0 eV. Although a smaller E g (2.6 eV) can be obtained in multiferroic BiFeO3, the value is still too high for optimal solar energy applications. Computational “materials genome” searches have predicted several exotic M O6 FE with E g M O4 tetrahedral network, KBiFe2O5, which features narrow E g (1.6 eV), high Curie temperature ( T c ~ 780 K) and robust magnetic and photoelectric activities. The high photovoltage (8.8 V) and photocurrent density (15 μA/cm2) were obtained, which is comparable to the reported BiFeO3. This finding may open a new avenue to discovering and designing optimal FE compounds for solar energy applications.
