Optimal Bandgap of Double Perovskite La-Substituted Bi2FeCrO6 for Solar Cells:an ab initio GGA+U Study

The ab initio generalized gradient approximation (GGA)+U study of multiferroic (La Bi )2FeCrO6 in pnma structure and ferri-magnetic order, including Hubbard corrections ( eV) for transition metal/rare earth d-electrons with 20 atoms cell, shows optimum local magnetic moments of (Cr , Fe equal to (−2.56, 4.14) μB and an ideal spin-down band gap of 1.54 eV. Tuned-band gap La-substituted double oxide perovskites BFCO should exhibit enhanced visible-light absorption and carrier mobility, thus could be convenient light absorbers and then efficient alternatives to wide-gap chalcopyrite absorber-based solar cells failing to achieve highest power conversion efficiencies, and even compete with their metal-organic halide perovskites counterparts.

BiFeO_3及Bi_2FeCrO_6的电子结构和光学特性

采用第一性原理方法计算了铁酸铋及掺铬铁酸铋的电子结构和光学特性等。计算结果表明BiFeO3及Bi2FeCrO6是间接带隙材料,所得到的BiFeO3和Bi2FeCrO6的带隙Eg=2.5eV和Eg=1.7eV,并讨论了Cr的掺入对能态密度、复介电函数,光学特性参数和Mulliken电荷分布的影响,所得结果对BiFeO3材料掺杂改性的研究具有参考价值。