Infrared‐to‐ultraviolet light‐absorbing BaTiO 3 ‐based ferroelectric photovoltaic materials
Infrared‐to‐ultraviolet light‐absorbing BaTiO 3 ‐based ferroelectric photovoltaic materials
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DOI：
10.1111/jace.16307
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发表时间：
2019-07
影响因子：
3.9
通讯作者：
Liyan Wu;A. Akbashev;A. Podpirka;J. Spanier;P. Davies
中科院分区：
文献类型：
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作者：
Liyan Wu;A. Akbashev;A. Podpirka;J. Spanier;P. Davies
铁电氧化物已被证明在开发新兴光伏技术方面很有前途，因为它具有多种机制，可以实现带隙以上的光电压和更高的效率。然而，传统铁电氧化物的宽带隙（2.7 - 4 eV）限制了它们对太阳光谱的利用。在这里，Ni-和Ni-Nb-取代的BaTiO 3的相稳定性，吸收性能，铁电性和光伏响应进行了探索，以评估其作为可见光吸收光伏材料的潜力。虽然Ni 2+的受体取代稳定了两个系统中的六方6 H多晶型物，但退火后处理允许Ba（Ti0.99Ni0.01）O2.99和（0.9）BaTiO 3-（0.1）Ba（Ni 1/2Nb 1/2）O2.75恢复四方3C相。伴随Ni和Ni-Nb取代的氧空位显著降低BaTiO 3的光学带隙至约1.5 eV，并且可以通过改变Ni：Nb比率在380和1000 nm之间系统地调节可见光吸收。Ba（Ti0.99Ni0.01）O2.99具有室温铁电性，饱和极化强度为18 μC/cm 2，剩余极化强度为1 μC/cm 2. Ni-Nb取代的（0.9）BaTiO 3-（0.1）Ba（Ni 1/2Nb 1/2）O2.75在77 K下表现出铁电响应，剩余极化为5 μC/cm 2，随着温度的升高而逐渐降低。两种组合物在AM 1.5G阳光模拟器下均表现出铁电可切换的光响应;对于铁电可切换的光响应，观察到8 nA/cm 2的最高可切换稳态电流。（0.9）钛酸钡-（0.1）巴（Ni 12 Nb 12）O2.75超过了之前BaTiO 3陶瓷样品研究中报道的结果（J Solid State Chem，1975; 12：193; Jpn J Appl Phys，2013; 52：09 KF 03）。
Ferroelectric oxides have been demonstrated to be promising in developing emerging photovoltaic technologies because of the various mechanisms that allow above‐band‐gap photovoltages and higher efficiencies. However, the wide band gaps of conventional ferroelectric oxides (2.7‐4 eV) limit their utilization of the solar spectrum. Here the phase stability, absorption properties, ferroelectric, and photovoltaic responses of Ni‐ and Ni‐Nb‐substituted BaTiO3were explored to evaluate their potential as visible‐light‐absorbing photovoltaic materials. Although the acceptor substitution of Ni2+stabilized a hexagonal 6H polymorph in both systems, post‐annealing treatments allowed restoration of a tetragonal 3C phase for Ba(Ti0.99Ni0.01)O2.99and (0.9)BaTiO3‐(0.1)Ba(Ni1/2Nb1/2)O2.75. The oxygen vacancies accompanying the Ni and Ni‐Nb substitutions significantly lower the optical band gap of BaTiO3to ~1.5 eV and the visible light absorption can be systematically tuned between 380 and 1000 nm by varying the Ni:Nb ratio. Room temperature ferroelectricity was observed in Ba(Ti0.99Ni0.01)O2.99with a saturation polarization = 18 μC/cm2and remnant polarization = 1 μC/cm2. The Ni‐Nb substituted composition (0.9)BaTiO3‐(0.1)Ba(Ni1/2Nb1/2)O2.75shows a ferroelectric response with a remnant polarization of 5 μC/cm2at 77 K, which gradually decreases as temperature increases. Both compositions exhibit ferroelectrically switchable photoresponses under an AM 1.5 G sunlight simulator; the highest switchable steady‐state current of 8 nA/cm2observed for (0.9)BaTiO3‐(0.1)Ba(Ni1/2Nb1/2)O2.75exceeds those reported in previous studies of BaTiO3ceramic samples (J Solid State Chem, 1975; 12: 193; Jpn J Appl Phys, 2013; 52: 09KF03).