We report on the spectral selection of excitation wavelength towards selective detection of aluminum and iron ions using dual emission polymer carbon dots (PCDs). PCDs were prepared from glucose and dilute sulfuric acid using one-pot solvothermal method. The PCDs emit blue light at 480 nm when excited at 340 nm, while emit red light at 590 nm when excited with 400 nm. Spectral selection (selection of excited state) showed sensitivity enhancement for detection of some metal ions. The PCDs showed fluorescence enhancement when combined with Al3+ ions with hypsochromic shift centered at 470 nm when excited at 440 nm. While the PCDs selectively quenched via addition of Fe3+ ions, when excited at 400 nm. The wavelength selection of the same carbon dots increases signal to noise ration. The PCDs showed thermo-sensing behavior from 0 C to 90 C with reasonably good reversibility. The PCDs acted as fluorescent probes for multicolor (green and yellow) imaging of MCF-7 cells while not inducing cell death, which indicates that the PCDs are biocompatible and nontoxic to the cells. Therefore, the PCDs can be used as probes for cell-imaging applications in vitro and in vivo. The PCDs proved to be a multi-purpose polymer carbon nanomaterial that can used for pharmaceutical analysis, bio-imaging and thermo-sensing while providing high accuracy, selectivity and a limit of detection in the nano range.
