Chemiresistive sensing platform based on PdO-PANI/ITO heterostructure for room temperature hydrogen detection

Abstract

Heterostructure of palladium oxide (PdO)-polyaniline (PANI)/indium tin oxide (ITO) have been used to enhance the sensitivity of chemiresistive sensors towards hydrogen (H2) gas at room temperature. The fabricated sensor assembly is facile and economical as it uses direct metallic electrical contact with the sensing element, which eliminates the need of expensive interdigitated electrodes (IDE). Pristine PANI, 5 wt%, and 10 wt% PdO-PANI nanocomposites are synthesized using one pot in-situ wet chemical polymerization method. Pristine PANI, 5 wt%, and 10 wt% PdO-PANI composites thin film are uniformly interfaced over sputtered indium tin oxide (ITO) layer coated glass substrate using spin coating process. Solid state sensing element consisting of PANI/ITO, 5 wt%, and 10 wt% PdO-PANI/ITO heterojunction has been used for detection of (1, 3, 10, and 20) % H2 concentration at room temperature. Two folds increase in the sensitivity of PdO-PANI nanocomposite towards 1% H2 gas concentration has been observed in comparison to pristine PANI based sensing element and further the sensitivity also increases as the percentage concentration of PdO within nanocomposite increases from 5 wt% to 10 wt% respectively. It has been observed that the proposed heterostructure based sensing assembly is highly sensitive towards H2 gas compared to similar previously reported sensors. With the onset of the hydrogen economy, this research work will pave the way in large scale production of sensitive and responsive handheld H2 gas sensors that can be used in common households along with industries.