Akademska digitalna zbirka SLovenije - logo
E-resources
Full text
Peer reviewed
  • A New Strategy for Humidity...
    Yoon, Ji-Wook; Kim, Jun-Sik; Kim, Tae-Hyung; Hong, Young Jun; Kang, Yun Chan; Lee, Jong-Heun

    Small (Weinheim an der Bergstrasse, Germany), 08/2016, Volume: 12, Issue: 31
    Journal Article

    The humidity dependence of the gas sensing characteristics of metal oxide semiconductors has been one of the greatest obstacles for gas sensor applications during the last five decades because ambient humidity dynamically changes with the environmental conditions. Herein, a new and novel strategy is reported to eliminate the humidity dependence of the gas sensing characteristics of oxide chemiresistors via dynamic self‐refreshing of the sensing surface affected by water vapor chemisorption. The sensor resistance and gas response of pure In2O3 hollow spheres significantly change and deteriorate in humid atmospheres. In contrast, the humidity dependence becomes negligible when an optimal concentration of CeO2 nanoclusters is uniformly loaded onto In2O3 hollow spheres via layer‐by‐layer (LBL) assembly. Moreover, In2O3 sensors LBL‐coated with CeO2 nanoclusters show fast response/recovery, low detection limit (500 ppb), and high selectivity to acetone even in highly humid conditions (relative humidity 80%). The mechanism underlying the dynamic refreshing of the In2O3 sensing surfaces regardless of humidity variation is investigated in relation to the role of CeO2 and the chemical interaction among CeO2, In2O3, and water vapor. This strategy can be widely used to design high performance gas sensors including disease diagnosis via breath analysis and pollutant monitoring. Humidity independent oxide semiconductor gas sensors are designed by dynamic self‐refreshing of In2O3 sensing surface assisted by layer‐by‐layer coated CeO2 nanoclusters. The CeO2 nanoclusters refreshed the sensing surface in a regenerative manner by scavenging chemically adsorbed hydroxyl groups and supplying oxygen ions. The unique self‐refreshing mechanism can provide a general solution for designing high performance gas sensors without humidity dependence.