Sn-Based Perovskite with a Wide Visible-Light Absorption Band Assisted by Hydride Doping
Sn-Based Perovskite with a Wide Visible-Light Absorption Band Assisted by Hydride Doping
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氢化物掺杂辅助的具有宽可见光吸收带的锡基钙钛矿
DOI：
10.1021/acs.chemmater.1c00460
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发表时间：
2021
影响因子：
8.6
通讯作者：
Maeda Kazuhiko
中科院分区：
文献类型：
--
作者：
Nakamura Masashi;Watanabe Hiroshi;Akamatsu Hirofumi;Fujii Kotaro;Yashima Masatomo;Hasegawa George;Inada Miki;Hayashi Katsuro;Maeda Kazuhiko
近年来，吸收可见光的窄禁带半导体由于其光功能应用而引起了极大的兴趣，包括异质结和太阳能电池。在此，我们报告了一种新的无铅钙钛矿材料，具有宽范围的可见光吸收，通过氢化物（H-）离子掺杂到BaSn0.7Y0.3O3−δ中成功合成。伴随H-离子掺杂的化学还原显著地将主体BaSn0.7Y0.3O3−δ的光学带隙从4.0 eV降低到2.0 eV。物理化学测量表明，BaSn0.7Y0.3O3−δ在B位经历了Sn 4+到Sn 2+的部分还原，同时保持了立方钙钛矿结构。密度泛函理论计算表明，来自Sn 2+孤对电子的电子态，位于价带顶部以上，有助于还原BaSn 0.7Y 0.3O 3 −δ的可见光吸收。通过Y3+取代Sn 4+将氧缺陷预先引入BaSnO 3中对于实现带隙的显著减小也是必不可少的。将还原的掺杂氢离子的BaSn0.7Y0.3O3-δ用作光电极材料，观察到高达600 nm的清晰阳极光响应，这表明该材料可用于光功能应用。这项工作的结果表明，利用立体活性孤对电子与H掺杂相结合，可以提供另一种方法来降低Sn（IV）基氧化物的带隙，这是无毒和便宜的，但通常是宽带隙半导体。
Visible-light-absorbing, narrow-gap semiconductors have attracted significant interest in recent years owing to their photofunctional applications, including heterogeneous photocatalysis and solar cells. Herein, we report a new Pb-free perovskite material with a wide range of visible-light absorption that was successfully synthesized via hydride (H–)-ion doping into BaSn0.7Y0.3O3−δ. Chemical reduction that accompanied H–-ion doping significantly reduced the optical band gap of the host BaSn0.7Y0.3O3−δfrom 4.0 to 2.0 eV. Physicochemical measurements revealed that BaSn0.7Y0.3O3−δunderwent the partial reduction of Sn4+to Sn2+at B-sites while maintaining the cubic perovskite structure. Density functional theory calculations showed that the electronic states derived from the Sn2+lone pair, which was located above the top of the valence band, contributed to the visible-light absorption of reduced BaSn0.7Y0.3O3−δ. The prior introduction of oxygen defects into BaSnO3by Y3+substitution for Sn4+was also indispensable to realize a significant reduction of the band gap. The reduced BaSn0.7Y0.3O3−δdoped with H–ions was applied as a photoelectrode material, and a clear anodic photoresponse of up to 600 nm was observed, which demonstrates that the material can be used for photofunctional applications. The results of this work suggest that the utilization of stereoactive lone pair of electrons in combination with H–doping may provide another approach to the band gap reduction of Sn(IV)-based oxides, which are nontoxic and less expensive, but generally wide-gap semiconductors.