Enhancing the response to ammonia and nitrogen dioxide of bare graphene through NiPc functionalization

In this work, in order to enhance the sensing capability of bare graphene, nickel phthalocyanine (NiPc) powder has been sublimated through a ther- mal evaporator in ultra-high vacuum, and deposited as a monolayer on a graphene on silicon carbide substrate. After characterization, the functionalized sample and a bare graphene layer have been settled on a properly designed platform, able to monitor the sensor response of both chemiresistors, allowing for a direct compar- ison of their performances under the same working condition. The results clearly demonstrate that the NiPc functionalization improves the response of bare graphene to ammonia and nitrogen dioxide by 40% and 30%, respectively, at 10 ppm concen- tration.