In this paper, in order to successfully achieve a fluorescent polyoxometalate (POM) probe with high luminescence, aggregation enhanced emission of POM is achieved by a self-assembly strategy. In detail, Eu-polyoxometalate (Na-9[EuW10O36]center dot 32H(2)O (EuNAtio)) and ionic-liquid-type imidazolium gemini surfactants ([C-14-n-C(14)im]Br-2, n = 2, 4, 6) constructed a vesicle with aggregation enhanced emission phenomenon. With the introduction of [C-14-n-C14im]Br2, the luminescence intensity increased sharply and compared the effect of the different space length of [C14-n-C14im]Br2, the introduction of [C-14-2-C(14)im]Br-2 had the best luminescence effect and the strongest luminescence of EuW10/[C-14-2-C(14)im]Br-2 was 32 times that of pure EuWio. Thus, a sensitive selective off-luminescence chemical sensor EuW10[C-14-2-C(14)im] Br-2 was developed for the label-free detection of Cr3+ and MnO4- in aqueous solution with lower detection limits of 0.926 mu M and 1.70 mu M, respectively. Collision between the fluorophore and Cr3+ or MnO4- caused dynamic quenching. Luminescence quenching of Cr3+ was attributed to Forster resonance energy transfer (FRET) while luminescence quenching of MnO4- was attributed to UV-vis competitive absorption. Our strategy for combining polyoxometalates with surfactants to construct aggregation enhanced emission systems is expected to provide new ways to develop simple, economical, fast and sensitive sensors in environmental applications such as metal ion detection. (C) 2019 Elsevier Inc. All rights reserved.