Self-Consistent Charge Density Functional Tight-Binding Study of Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) Ammonia Gas Sensor.
Geometric and electronic properties of 3,4-ethylenedioxythiophene (EDOT), styrene sulfonate (SS), and EDOT: SS oligomers up to 10 repeating units were studied by the self-consistent charge density functional tight-binding (SCC-DFTB) method. An application of PEDOT:PSS for ammonia (NH3) detection was highlighted and investigated both experimentally and theoretically. The results showed an important role of H-bonds in EDOT:SS oligomers complex conformation. Electrical conductivity of EDOT increased with increasing oligomers and doping SS due to enhancement of π conjugation. Printed PEDOT:PSS gas sensor exhibited relatively high response and selectivity to NH3. The SCC-DFTB calculation suggested domination of direct charge transfer process in changing of PEDOT:PSS conductivity upon NH3exposure at room temperature. The NH3molecules preferred to bind with PEDOT:PSS via physisorption. The most favorable adsorption site for PEDOT:PSS-NH3interaction was found to be at the nitrogen atom of NH3and hydrogen atoms of SS with an average optimal binding distance of 2.00 Å.
Department of Physics, Faculty of Science, Kasetsart University, 10900, Chatuchak, Bangkok, Thailand.|Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi, 11000, Nonthaburi, Thailand.
Ampaiwan
A
Marutaphan
Department of Physics, Faculty of Science, Kasetsart University, 10900, Chatuchak, Bangkok, Thailand.
Yotsarayuth
Y
Seekaew
Department of Physics, Faculty of Science, Kasetsart University, 10900, Chatuchak, Bangkok, Thailand. Chatchawal.w@ku.ac.th.
Chatchawal
http://orcid.org/0000-0002-5613-6615
C
Wongchoosuk
Ammonia gas sensor; Conducting polymers; PEDOT:PSS; QM/MD simulation; SCC-DFTB