Silicon quantum dots and MOFs hybrid multicolor fluorescent nanosensor for ultrasensitive and visual intelligent sensing of tetracycline

Metal-organic frameworks (MOFs) with multiple emission centers have recently bloomed out as attractive fluorescence (FL) sensors due to their high sensitivity and selectivity to multiple target species. Herein, a novel silicon quantum dots (SiQDs) hybride MOFs multicolor fluorescent nanosensor ([email protected]) was elaborately tailored for tetracycline detection, using in situ composition of [email protected] and further decoration of Eu3+ on its surface due to the coordination of free carboxyl groups and Eu3+. In this nanosensor, both the SiQDs with blue emission (λem=472 nm) and Eu3+ ions with potential red FL (λem=616 nm) can be served as specific recognition units of TC based on the inner filter effect (IFE) and the antenna effect, respectively. Upon the addition of TC, the emission intensity of the SiQDs decreased slowly while that of the Eu3+ ion increased significantly, accompanied by obvious blue-red color switching, resulting in ultrahigh sensitivity (detection limit 3.16 nM). Furthermore, real-time visual determination of TC in actual samples was successfully achieved. With the assistance of color scanning APP in smart phones, real-time intelligent determination of TC can be realized.