Figure 1.

Fabricating flowchart of the gas sensing materials and gas sensors. (A1-A4) Flowchart of gas sensing films fabrication shows the specific procedures of synthesis of NiO films on glass substrates. This unique film structure was fabricated via a chemical controllable reaction combined with high-temperature oxidation approach. (B1-B3) Flowchart shows the assemble processes and configuration of the gas sensing devices based as-prepared NiO films, which mainly contained the preparation of electrodes and the connection between NiO sensing materials and electrodes.