Photovoltaic Properties of Multiferroic Materials

Dr. Sheng Ju (Hosted by Yang), Department of Physics, Soochow University, Suzhou, China and Department of Physics, University of California, Berkeley

Ferroelectric oxides are attractive materials for constructing efficient solar cells. Nevertheless, a wide band gap of nearly 3.0 eV in these ferroelectric oxides would result in poor overall sunlight absorption and, hence, low energy conversion efficiency. In this talk, we demonstrate that double-perovskite semiconductors ScFe1−xCrxO3 with a narrow band gap of approximately 1.8 eV would simultaneously exhibit large ferroelectric polarization (100  μC/cm2) and ferrimagnetic magnetization (170  emu/cm3). Within a Schottky-based model for a typical sandwich solar-cell structure, a power-conversion efficiency of 9.0% can be reached by neglecting all other sources of photovoltaicity in ferroelectric materials. This value is larger than the largest value of 8.1% observed in ferroelectric oxides. Furthermore, these double perovskites are found to be single-spin semiconductors, and the obtained photocurrent is fully spin polarized over almost the entire Sun spectrum. These fascinating advantages would make ScFexCr1−xO3 semiconductors promising candidates for highly efficient solar cells and spin photovoltaic devices.