Extremely Sensitive and Selective NO Probe Based on Villi-like WO3 Nanostructures for Application to Exhaled Breath Analyzers
Extremely Sensitive and Selective NO Probe Based on Villi-like WO3 Nanostructures for Application to Exhaled Breath Analyzers
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DOI：
10.1021/am402456s
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发表时间：
2013-11-13
影响因子：
9.5
通讯作者：
Jang, Ho Won
中科院分区：
文献类型：
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作者：
Moon, Hi Gyu;Choi, You Rim;Jang, Ho Won
采用掠射角沉积法(GAD)在具有铂交叉指电极的SiO_2/Si衬底上制备了具有一维绒毛状纳米翅的自组装WO_3薄膜纳米结构。用GAD方法在室温下沉积WO_3薄膜，得到了具有大纵横比和孔隙率的各向异性纳米结构，其相对表面积约为普通WO_3薄膜的32倍。在相对湿度为80%的温度下，WO3VLNF传感器对一氧化氮(NO)有极高的响应(S)，而对乙醇、丙酮、氨和一氧化碳的响应可以忽略不计。这种对NO的高灵敏度和选择性归因于在单个WO_3 VLNF和WO_3对NO的高灵敏度之间的窄颈势垒的高效调节。该传感器对NO的理论检测下限有望低至万亿分之八十八(Ppt)。由于NO是公认的哮喘慢性呼吸道炎症的生物标志物，在高湿环境下对NO具有前所未有的高响应性和选择性，以及对NO的ppt水平检测下限，这表明WO_3 VLNF在高性能呼吸分析仪中具有巨大的潜力。
Self-assembled WO3 thin film nanostructures with 1-dimensional villi-like nanofingers (VLNF) have been synthesized on the SiO2/Si substrate with Pt interdigitated electrodes using glancing angle deposition (GAD). Room-temperature deposition of WO3 by GAD resulted in anisotropic nanostructures with large aspect ratio and porosity having a relative surface area, which is about 32 times larger than that of a plain WO3 film. A WO3 VLNF sensor shows extremely high response to nitric oxide (NO) at 200 degrees C in Time (s) 80% of relative humidity atmosphere, while responses of the sensor to ethanol, acetone, ammonia, and carbon monoxide are negligible. Such high sensitivity and selectivity to NO are attributed to the highly efficient modualtion of potential barriers at narrow necks between individual WO3 VLNF and the intrinsically high sensitivity of WO3 to NO. The theoretical detection limit of the sensor for NO is expected to be as low as 88 parts per trillion (ppt). Since NO is an approved biomarker of chronic airway inflammation in asthma, unprecedentedly high response and selectivity, and ppt-level detection limit to NO under highly humid environment demonstrate the great potential of the WO3 VLNF for use in high performance breath analyzers.