▎ 摘　　要

New type of "turn-on" fluorescent sensor for Cs ion was developed using a composite of blue-emissive conjugated polymer (CP) and graphene oxide (GO). Ethylene glycol units were introduced to the side chain of CP, which could interact with Cs ions. The CP and GO formed a stable, nonfluorescent composite, because of hydrophobic and pi-pi interactions between them. In the presence of Cs ions, the CP was released from the CP-GO composite because of higher affinity of Cs ions with ethylene glycol units in the CP. Such a weaker interaction between CP and GO led to the recovery of initial blue fluorescence of the CP. The degree of fluorescence restoration would be a measure of the concentration of Cs ions. Thus, fluorescence "turn-on" from CP-GO was attributed to the presence of Cs ions.