Giant and controllable humidity sensitivity achieved in (Na plus Nb) co-doped rutile TiO2
Giant and controllable humidity sensitivity achieved in (Na plus Nb) co-doped rutile TiO2
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(Na + Nb) 共掺杂金红石 TiO2 实现了巨大且可控的湿度灵敏度
DOI：
10.1016/j.snb.2019.05.019
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发表时间：
2019-08-15
影响因子：
8.4
通讯作者：
Wang, C. C.
中科院分区：
文献类型：
--
作者：
Li, T. Y.;Si, R. J.;Wang, C. C.
采用固相反应法制备了（Na_（0.25）Nb_（0.75））（x）Ti_（1-x）O_2（NNTO，x = 0，0.01，0.02，0.05）粉体，并将其用作湿敏材料。系统研究了NNTO基电容式湿敏元件的湿敏特性。结果表明，随着掺杂量的增加，薄膜的湿敏性增强。在x = 0.05的样品中实现了前所未有的13，705 pF/%RH的高湿度灵敏度，具有良好的重复性和快速的响应/恢复时间。氧空位、Nb-Ti（中心点）离子和NaNbO 3的第二相的点缺陷被认为是激发湿敏性能的原因。有趣的是，湿度灵敏度可以很容易地调谐由一个小的直流偏压0-4 V的抑郁症的湿度引起的麦克斯韦-瓦格纳松弛和中性化的充电点缺陷，由于偏压注入电子被发现是可调节性的原因。为研制性能优良的可调电容式传感器奠定了基础。
The (Na0.25Nb0.75)(x)Ti1-xO2 (NNTO, with x = 0, 0.01, 0.02, and 0.05) powders were prepared by solid-state reaction and used as humidity sensing materials. The humidity sensitive properties of the NNTO based capacitive-type sensors were systematically investigated. Our results revealed that the humidity sensitivity increases with the increasing of doping level. An unprecedented high humidity sensitivity of 13,705 pF/%RH with good repeatability and fast response/recovery time were achieved in the sample with x = 0.05. The point defects of oxygen vacancies, Nb-Ti(center dot) ions, and the secondary phase of NaNbO3 were argued to be responsible for the exciting humidity sensitive properties. Interestingly, the humidity sensitivity can be easily tuned by a small dc bias of 0-4 V. The depression of the humidity-induced Maxwell-Wagner relaxation and the neutralization of the charged point defects due to bias-injected electrons were found to be the cause of the adjustability. This work paves the way for developing capacitive-type sensors with adjustable and excellent performances.