Carbon Dot-Functionalized Solution-Gated Graphene Transistors for Highly Sensitive Detection of Cobalt(II) Ions

A carbon dot-functionalized solution-gated graphene transistor (CD-SGGT) was designed and prepared via the modification of CDs on the gate of SGGT. The above CDs were hydrothermally synthesized using DL-thioctic acid and triethylenetramine as C, N and S sources. The average size of CDs was ~6.2 nm, and there were many amino and carboxyl groups on the CDs’ surfaces. The CDs was then used as a probe for preparation of CD-SGGT sensor for the cobalt(II) (Co2+) ions detection. The CD-SGGT sensor showed excellent sensitivity and high selectivity. Remarkably, the limit of detection (LOD) reached 10−19M. The linear detection range was obtained from 10−19to 10−15M. Additionally, the CD-SGGT also showed fast response and good stability.Keywords:carbon dots;graphene;transistor;cobalt(II) ions;high selectivity;high sensitivity