Switchable and adjustable AIE activity of Pt(II) complexes achieving swift-responding and highly sensitive oxygen sensing

AIE-active luminogens are attractive for bioimaging, sensors, and optical detections. However, controllably switching and adjusting the AIE activity of luminogens in aqueous media to perform the best of AIE performance under appropriate water fraction remains a challenge. Herein, we report the first case of switchable and adjustable AIE activity based on Pt(II) complexes. The AIE activity of Pt(II) complexes in aqueous media can be flexibly switched and adjusted via finely tuning the rotation activity of the substituents. And the rotation activity of the substituents have been experimentally confirmed by the luminescent lifetimes and theoretically verified by the dipole moments of Pt(II) complexes. Furthermore, luminescent oxygen sensing films were constructed by combining the AIE-active Pt(II) complexes with commercially available, low-cost ethyl cellulose (EC). With the attenuation of EC film thickness, swift-responding quenching/recovering cycles (7.7 s) of the PtTPA-EC(N10) oxygen sensing film were demonstrated. And the controllable AIE property of Pt(II) complexes can effectively improve the oxygen sensitivity and the homogeneity of oxygen sensing films.