Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China.
Material and Chemical Research Laboratories and Nanotechnology Research Center, Industrial Technology Research Institute, Hsinchu, Taiwan 310, Republic of China.
Sci Rep. 2017 Mar 24;7:45164. doi: 10.1038/srep45164.
Remarkably enhanced photovoltaic effects have been observed in the heterostructures of p-type A-site Nd-doped BiFeO (BiNd)FeO (or BFONd) polycrystalline ceramics and the n-type ITO thin film. The maximum power conversion is ~0.82%, which is larger than 0.015% in BiFeO (BFO) under blue-ultraviolet irradiation of wavelength λ = 405 nm. The current-voltage (I-V) characteristic curve suggests a p-n junction interface between the ITO thin film and BFO (or BFONd) ceramics. The band gaps calculated from first-principles for BFO and BFONd are respectively 2.25 eV and 2.23 eV, which are consistent with the experimental direct band gaps of 2.24 eV and 2.20 eV measured by optical transmission spectra. The reduction of the band gap in BFONd can be explained by the lower electronic Fermi level due to acceptor states revealed by first-principles calculations. The optical calculations show a larger absorption coefficient in BFONd than in BFO.
在 p 型 A 位 Nd 掺杂 BiFeO（BiNd）FeO（或 BFONd）多晶陶瓷与 n 型 ITO 薄膜的异质结构中，观察到显著增强的光伏效应。最大的功率转换效率约为 0.82%，大于波长为 λ=405nm 的蓝紫外光照射下的 BiFeO（BFO）的 0.015%。电流-电压（I-V）特性曲线表明，ITO 薄膜与 BFO（或 BFONd）陶瓷之间存在 p-n 结界面。第一性原理计算得出的 BFO 和 BFONd 的能带隙分别为 2.25eV 和 2.23eV，与光学透射光谱测量得到的实验直接能带隙 2.24eV 和 2.20eV 一致。BFONd 中能带隙的减小可以用第一性原理计算揭示的受主态导致的电子费米能级降低来解释。光学计算表明 BFONd 的吸收系数大于 BFO。
