Dai Tiantian, Deng Zanhong, Wang Shimao, Fang Xiaodong, Meng Gang
Anhui Provincial Key Laboratory of Photonic Devices and Materials, Anhui Institute of Optics and Fine Mechanics and Key Lab of Photovoltaic and Energy Conservation Materials, Chinese Academy of Sciences, Hefei 230031, China.
Research Center for Intelligent Sensing, Zhejiang Lab, Hangzhou 311121, China.
Nanoscale. 2022 Mar 31;14(13):5002-5009. doi: 10.1039/d2nr00609j.
With features of innate tunnels and oxygen vacancies derived from a unique geometrical structure and sub-stoichiometric compositions, WO nanowires have been explored as multifunctional materials with diverse applications. Though thermal oxidation offers a facile method to synthesize patterned WO nanowires, the relatively high growth temperature (≳500 °C) hinders their emerging applications in flexible or wearable electronics. In this work, aiming to lower the growth temperature of WO nanowires by thermal oxidation, the temperature and oxygen partial pressure dependent growth has been systematically investigated for both W films and powders. WO nanowires could be steadily obtained with appropriate temperature and oxygen pressure ranges for both cases, while the growth temperature of a W film (metastable β phase dominant) could be much lower than that of W powder (α phase). The structural analysis indicates that metastable β-W is susceptible to oxidation in comparison with α-W and thus generates oxidation-induced chemical compression for nanowire growth. The growth temperature of WO nanowires could be reduced to . 400 °C, which paves the way for the patterning of WO nanowires on indium-tin-oxide (ITO) glass substrates and flexible substrates.
由于具有源自独特几何结构和亚化学计量组成的固有隧道和氧空位，WO纳米线已被探索作为具有多种应用的多功能材料。尽管热氧化提供了一种合成图案化WO纳米线的简便方法，但相对较高的生长温度（≳500°C）阻碍了它们在柔性或可穿戴电子产品中的新兴应用。在这项工作中，为了通过热氧化降低WO纳米线的生长温度，系统地研究了W薄膜和粉末在温度和氧分压依赖下的生长情况。对于这两种情况，在适当的温度和氧压力范围内都可以稳定地获得WO纳米线，而W薄膜（以亚稳β相为主）的生长温度远低于W粉末（α相）。结构分析表明，与α-W相比，亚稳β-W更容易氧化，从而产生氧化诱导的化学压缩以促进纳米线生长。WO纳米线的生长温度可以降低到400°C，这为在氧化铟锡（ITO）玻璃基板和柔性基板上图案化WO纳米线铺平了道路。
