TY - JOUR
T1 - A new strategy for humidity independent oxide chemiresistors
T2 - Dynamic self-refreshing of In2O3 sensing surface assisted by layer-by-layer coated CeO2 nanoclusters
AU - Yoon, Ji Wook
AU - Kim, Jun Sik
AU - Kim, Tae Hyung
AU - Hong, Young Jun
AU - Kang, Yun Chan
AU - Lee, Jong Heun
N1 - Funding Information:
through the reactions ( 4) , ( 5) , ( 6) , ( 7) is supported by the humidity independent sensor resistance in the present study (Figure 6 b5–b7). Scheme 1 a–d (involving reactions ( 4) , ( 5) , ( 6) , ( 7) ) can occur in a repetitive manner, providing a novel mechanism for the regenerative refresh of the In 2O 3 surfaces and Ce 4+/Ce 3+ by OH scavenging and oxygen readsorption. Therefore, the CeO 2 nanoparticles on the In 2O 3 surface play a key role in (1) scavenging of hydroxyl groups (OH) on the In 2O 3 surface, and (2) maintaining a constant concentration of negatively charged oxygen ions by assisting oxygen ion read-sorption. This mechanism results in the observed humidity independent gas response and sensor resistance. Note that the resistance in air ( Ra) of the 11.7 Ce-In 2O 3 sensor decreased immediately after exposure to humidity and rapidly recovered
Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2016R1A2A1A05005331).
PY - 2016/8
Y1 - 2016/8
N2 - 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.
AB - 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.
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U2 - 10.1002/smll.201601507
DO - 10.1002/smll.201601507
M3 - Article
C2 - 27357165
AN - SCOPUS:84981532057
VL - 12
SP - 4229
EP - 4240
JO - Small
JF - Small
SN - 1613-6810
IS - 31
ER -