Study of the NO2 sensing mechanism of PEDOT-RGO film using in situ Raman Spectroscopy

• Published in: Sensors and actuators. B, Chemical Vol. 260; pp. 1025 - 1033
• Main Authors: Dunst, K.J., Trzciński, K., Scheibe, B., Sawczak, M., Jasiński, P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2018
• Subjects: In situ Raman spectroscopy; NO2 gas sensor; PEDOT-RGO; NO2 gas sensor; In situ Raman spectroscopy; PEDOT-RGO
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2018.01.089

•NO2 as a strong oxidant causes overoxidation of the PEDOT polymer.•RGO “protects” the polymer PEDOT against overoxidation process.•NO2 reacts more readily with RGO than with PEDOT in PEDOT-RGO composite.
In this work, the mechanism of the NO2 reaction with PEDOT-RGO composite film has been investigated via in situ Raman spectroscopy. Reduced graphene oxide (RGO), poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO) and poly(3,4-ethylenedioxytiophene)/ClO4− (PEDOT/ClO4−) films were fabricated using an electrodeposition method and used as resistance sensors of gaseous nitrogen dioxide. The experimental results indicate that NO2 causes overoxidation of the PEDOT polymer (PEDOT/ClO4− film) which leads to resistance increase and irreversible response. In contrast, the PEDOT-RGO response in the presence of NO2 is reversible. During short NO2 exposure, PEDOT from the PEDOT-RGO composite does not react to the gas but the presence of RGO in the PEDOT-RGO composite does not affect the overoxidation potential. It was found that the nitrogen dioxide reacts more readily to reduced graphene oxide, thus RGO “protects” the polymer against the adverse overoxidation process.