Bian Zhiping, Zhao Jiangtao, Cao Heng, Dong Yongqi, Luo Zhenlin
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China.
Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
ACS Appl Mater Interfaces. 2021 Mar 24;13(11):13419-13424. doi: 10.1021/acsami.1c01165. Epub 2021 Mar 12.
Hydrogenation, an effective way to tune the properties of transition metal oxide (TMO) thin films, has been long awaited to be performed safely and without an external energy input. Recently, metal-acid-TMO has been reported to be an effective approach for hydrogenation, but the requirement of acid limits its application. In this work, the reversible and rapid hydrogen doping of WO in NaOH(aq) | Al(s) | WO(s) is revealed by structural and electrical measurements. Accompanied by the structural phase transition identified by X-ray diffraction, the electric resistance of the WO film is found to be able to change by 5 orders of magnitude. A significant electrical response of touching, 8-fold in amplitude and 3 s in a cycle, can be achieved in the low-resistance state. These reactions are reversible at room temperature. This study unambiguously proves that the hydrogenation-driven dynamic phase transition of WO in metal-solution-WO systems could occur not only in acid solutions but also in some non-acid environments. Unlike the monotonic increase of resistance revealed during HWO to WO transition, an intriguing non-monotonic evolution was found for crystal lattice parameter , indicating that the mechanism of WO hydrogenation involves a series of metastable states, more comprehensive and reasonable. This work sheds light on the potential applications of metal-solution-TMO hydrogenation in touching sensors, circuits survey, and information storage.
氢化是调节过渡金属氧化物（TMO）薄膜性能的有效方法，长期以来人们一直期待能够在无需外部能量输入的情况下安全地进行氢化。最近，有报道称金属-酸-TMO是一种有效的氢化方法，但对酸的要求限制了其应用。在这项工作中，通过结构和电学测量揭示了在NaOH（水溶液）|Al（固体）|WO（固体）体系中WO的可逆且快速的氢掺杂现象。伴随着X射线衍射确定的结构相变，发现WO薄膜的电阻能够改变5个数量级。在低电阻状态下，可以实现显著的触摸电响应，幅度为8倍，周期为3秒。这些反应在室温下是可逆的。这项研究明确证明，金属-溶液-WO体系中WO的氢化驱动动态相变不仅可以在酸性溶液中发生，也可以在一些非酸性环境中发生。与HWO向WO转变过程中电阻单调增加不同，发现晶格参数呈现出有趣的非单调演化，这表明WO氢化机制涉及一系列亚稳态，更加全面合理。这项工作为金属-溶液-TMO氢化在触摸传感器、电路测量和信息存储方面的潜在应用提供了线索。
