Facilely prepared carbon dots and rare earth ion doped hybrid composites for ratio-metric pH sensing and white-light emission

A facile method was developed to synthesize fluorescent carbon-dot Eu3+ hybrid composites (CD-Eu-HCs) by one-pot hydrothermal methods. The prepared composites demonstrate unique dual fluorescence which originates from the blue emission of the CDs and intrinsic photoluminescence of the Eu3+ ions, respectively. Moreover, such dual fluorescent characteristics show quite different responses for different pH value environments and have been developed in a ratiometric pH sensor. Lastly, they can realize white light emission by co-doping of Tb3+ and the color temperature becomes tunable by adjusting the relative proportion of Eu3+.