Wet process-prepared thick films of WO3 for NO2 sensing

Yong Gyu Choi, Go Sakai, Kengo Shimanoe, Norio Miura, Noboru Yamazoe

研究成果: ジャーナルへの寄稿会議記事査読

59 被引用数 (Scopus)


Preparation of an aqueous sol of WO3·2H2O starting from Na2WO4 through an ion-exchange method, coupled with post-treatments (ultrasonic and/or centrifugal), was found to give WO3·2H2O gels which differed in morphology and preferred orientation depending on the kinds and conditions of the post-treatments. The morphology of the gels was well inherited topotaxically by the dehydrated phases of WO3·H2O and tungsten trioxide (WO3), allowing to control the morphology of WO3 by the wet processing. The WO3 thick film devices, fabricated from the gels and calcined at 300°C, were found to show very different sensor responses to NO2 in air depending on the morphology of WO 3. That is, poorly developed, small lamellas of WO3 obtained by the ultrasonic treatment for a prolonged time (5h) gave the most sensitive device at 200°C, which could respond to as low as 10ppb NO 2, while well developed, thin lamellas of WO3 obtained by the centrifugal treatment for a prolonged time (10h) gave the most sensitive one at 300°C. In order to understand the dependence of sensor response on the morphology of WO3, several other methods were also adopted for preparing WO3. It was found that all of the sensor response data collected at 300°C could be related fairly well with the thickness of WO3 lamellas or the diameter of WO3 grains, whereas such a relationship became less certain at 200°C.

ジャーナルSensors and Actuators, B: Chemical
出版ステータス出版済み - 10月 15 2003
イベントSelected Papers from Eurosensors XVI - Prague, チェコ共和国
継続期間: 9月 15 20029月 18 2002

!!!All Science Journal Classification (ASJC) codes

  • 電子材料、光学材料、および磁性材料
  • 器械工学
  • 凝縮系物理学
  • 表面、皮膜および薄膜
  • 金属および合金
  • 電子工学および電気工学
  • 材料化学


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