中文摘要：

采用溶胶–凝胶法,用乙二醇甲醚作溶剂溶解Bi（NO3）3、Fe（NO3）3和La（NO3）3制备前体溶液,通过化学溶液沉积法在FTO导电玻璃基板上合成La3＋掺杂的BiFeO3（BFO）薄膜,并研究了La3＋掺杂对BiFeO3的能带及其光伏性能的影响。BiFeO3薄膜呈多晶钙钛矿结构,且随着La3＋掺杂量的增加,BiFeO3的晶格常数依次递减。掺杂10%La3＋的BiFeO3的能隙比未掺杂时稍有减小,为2.71 eV,随着La3＋掺杂量的增加,BiFeO3的能隙增加到2.76 eV。采用改良法制备的La3＋的掺杂量为10%的BiFeO3薄膜的最大开路电压为0.4 V,具有良好的光伏性能。

英文摘要：

The La3＋ doped BiFeO3（BFO） thin films were fabricated by Sol-Gel method.The precursor solution was synthesized by dissolving Bi（NO3）3,Fe（NO3）3 and La（NO3）3 in 2-methoxyethanol and BiFeO3 thin films were grown by chemical solution deposition on fluorine doped tin oxide（FTO） glass substrate.The influence of La3＋ doping on the band gap and photovoltaic properties of BiFeO3 was studied.The BiFeO3 thin films exhibited polycrystalline-phase perovskite structure.The lattice parameter of BiFeO3decreased with La3＋ addition increasing.The band gap of BiFeO3 doped with 10% La3＋ doping was 2.71 eV,a little smaller than that of the undoped one.The bandgap of BiFeO3 increased to 2.76 eV with the increase of La3＋ doping.The maximal open circuit voltage of 10% La3＋-doped BiFeO3 prepared by modified method reached 0.4 V,showing good photovoltaic properties.