Red-emissive carbon dots (CDs) were synthesized by one-step hydrothermal technique using citric acid (CA), and urea in N,N-dimethylformamide (DMF) solution. The CDs has an average diameter of 2.3 nm, excitation/emission maxima at 553/606 nm, and a low photoluminescence quantum yield (4%). Fluorescence is weakly quenched by the ions Fe(3+), Hg(2+), Cu(2+), Co(2+), Zn(2+), Ca(2+), Ni(2+), and Pb(2+). After addition of cetyltrimethyl ammonium ion (CTAB), electrostatic interaction between negatively charged CDs and CTAB causes the CDs to self-aggregate. The formation of CD/CTAB increases the avera...
