Abstract
Polyethyleneimine (PEI) and chromium oxide (Cr
2
O
3
) with different weight percentages were chosen for sensing carbon dioxide (CO
2
). Four divergent varieties of sensors with different concentrations of Cr
2
O
3
in PEI were fabricated by drop-casting the sensitive films on prepared interdigitated electrodes (IDE) from copper clad. X-ray, absorbance, morphological, and compositional studies were carried on Cr
2
O
3
nanoparticles by x-ray diffractometry (XRD), UV–Visible spectrometry, and field-emission scanning electron microscopy (FESEM). Response proficiency for all the fabricated sensors was meticulously examined at room temperature. Solitary proficiencies of resistance versus gas concentration, sensitivity, repeatability, and precise response time and recovery time measurements were examined. It was epitomized that the appropriate weight ratio of PEI and Cr
2
O
3
was critical for CO
2
sensing. A reasonable correlation between the sensing responses of the developed sensors to carbon dioxide under nitrogen was achieved.