[18a-A37-1~11] 17.2 Graphene

10:30 AM - 10:45 AM JST(1:30 AM - 1:45 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation AwardEnglish Presentation

[18a-A37-6] Reduced Cobalt-Phthalocyanine Covalently Functionalized Graphene Oxide for Fast, Sensitive, and Reproducible Ammonia Sensors.

〇(M2)Yuxiang Shen¹, Ryo Toyoshima¹, Ken Uchida¹ (1.Fac. of Eng., UTokyo)

Keywords:

gas sensor,graphene,phthalocyanine

Developing advanced ammonia sensors is important for future non-invasive early disease diagnosis. Organic systems can show good selectivity, but the response is slow, and it is difficult to achieve good stability due to agglomeration. Here, we report on a metal-organic sensor system that can combine excellent stability and high-speed response. The sensor was fabricated by covalently linking graphene with cobalt (II) 2,9,16,23-tetra(carboxy)phthalocyanine (CoTCPc) through a wet chemical reaction, followed by reduction and electron beam deposition of Cr/Au electrodes. Most notably, high operating temperatures have been realized in the graphene-porphyrin system. Because of the strong covalent bonding, the porphyrin molecule's range of motion is constrained, and the results show its good stability even after 100 days of operation at 473K. Moreover, the response time is significantly shortened (from 1 h to 2 min) while the sensitivity to ammonia is greatly improved because of the unique 18-electron conjugation system of the CoTCPc. It can respond quickly to NH₃ at 437K and was unaffected by humidity below 60% RH and H₂ after reduction. Finally, the adsorption process was further investigated by neural-network-potential (NNP)-based molecular dynamic simulations, and the self-diffusion coefficients explain that the stability of the device was more than three orders of magnitude better than the traditional case