A dual-mode fluorescent probe based on carbon dots for detecting solution polarity

Fluorescent probes always attract huge attention. In particular, carbon dots, due to their unique biocompatibility and variable fluorescence characteristics, can be used in multiple fields and were fulled of expectation by researchers. Since the advent of the dual-mode carbon dots probe, which greatly improved the accuracy of quantitative detection, there are higher hopes for dual-mode carbon dots probes. Herein, we have successfully developed a new dual-mode fluorescent carbon dots probe based on 1,10-phenanthroline (Ph-CDs). Ph-CDs detect the object to be measured based on both down-conversion luminescence and up-conversion luminescence at the same time, different from the reported dual-mode fluorescent probes which are based on the wavelength and intensity changes in down-conversion luminescence. As-prepared Ph-CDs have good linear relationships with the polarity of solvents in down-conversion luminescence (R2 = 0.9909) and up-conversion luminescence (R2 = 0.9374), respectively. Hence, Ph-CDs provide a new in-depth insight into the design of fluorescent probes with dual-mode detection and they can give more accurate, reliable and convenient detection results.