A high-sensitive ratiometric luminescent thermometer based on dual-emission of carbon dots/Rhodamine B nanocomposite

A core-shell nanocomposite based on carbon dots (CD)/Rhodamine B (RhB) is realized by a facile method. The composite particles show spherical shape with narrow size distribution, non-agglomeration and smooth surface. The as-obtained nanocomposite shows the characteristic dual-emission of thermal-stable CD blue emission and thermal-sensitive RhB red emission at a single excitation wavelength. The fluorescence intensity ratio (FIR) is found to have a good linear relationship ( R 2  > 0.993) with temperature, while the corresponding maximum absolute and relative sensitivity is 2.01% K −1 and 1.39% K −1 in range of 283–373 K. The research provides a simple approach to create novel dual-emitting nanocomposites for temperature sensing application in micron-scale and biological field.