Machine-intelligent inkjet-printed α-Fe2O3/rGO towards NO2 quantification in ambient humidity

Tien Chun Wu, Jie Dai, Guohua Hu, Wen Bei Yu, Osarenkhoe Ogbeide, Andrea De Luca, Xiao Huang, Bao Lian Su, Yu Li, Florin Udrea, Tawfique Hasan

Research output: Contribution to journalArticlepeer-review


Metal oxides (MOx) represent one of the most investigated chemiresistive gas sensing platforms in spite of the challenges in selectivity to analytes and interference from humidity (RH). While selectivity is traditionally improved by cross-referencing sensor arrays, interferences from humidity (RH) in ambient environment, to which the majority of the MOx materials are susceptible, cannot be inherently quantified. For standalone MOx sensors, it is therefore difficult to discriminate responses from analytes and humidity. We develop a framework which employs temperature modulation (TM) algorithms and machine learning (ML) approaches using principal component analysis (PCA) and cluster analysis of transient features, to quantify NO2 concentrations under specific RH conditions. With a single inkjet-printed MOx/reduced graphene oxide (rGO) complementary metal-oxide-semiconductor (CMOS)-integrated sensor, we achieve an overall discrimination accuracy of 97.3%. Our approach may enable the development of predictive systems for humidity sensitive sensors under ambient moisture conditions, towards the realisation of low-power, miniaturised adaptive air quality monitoring.

Original languageEnglish
Article number128446
JournalSensors and Actuators, B: Chemical
Publication statusPublished - 15 Oct 2020
Externally publishedYes


  • Cluster analysis
  • Electronic nose
  • Factor analysis
  • Inkjet on CMOS
  • Machine learning
  • Principal component analysis
  • Temperature modulation


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