CsPbBr3 PQDs in EuAPO-5 Zeolite: Highly Stable Fluorescent-Traffic-Light Sensor for Point-of-Care Response of Tetracycline and Temperature

Abstract

Fluorescent point-of-care (POC) sensors with specific target recognition capability through signaling mechanisms have promising applications in areas such as environmental monitoring and food detection. Herein, a solvent-free method was developed to prepare a novel POC sensor based on dual-luminescent CsPbBr3@EuAPO-5 composite that enabled the multiple sensing of tetracycline (TC) and temperature in a unique fluorescent-traffic-light manner. Benefiting from the confinement effect of EuAPO-5 zeolite, the CsPbBr3 perovskite quantum dots (PQDs) exhibits extraordinary luminescent stability even soaking in water for 30 days. During TC detection, the effective absorbed energy transfer from TC to Eu3+ in EuAPO-5 zeolite through the antenna effect enhances the red emission of Eu3+, and meanwhile a internal filtering effect (IFE) between the TC molecule and CsPbBr3 PQDs results in the green emission quenching of CsPbBr3. Combining the colorimetric determination using a smartphone-based analysis application (APP), the CsPbBr3@EuAPO-5 can serve as a portable POC sensor for TC monitoring in aqueous solution with a low detection limit of 0.013µM in a linear range of 0-140µM. Besides, ratiometric temperature sensing behavior of CsPbBr3@EuAPO-5 for high temperature warning in a fluorescent-traffic-light manner was also achieved, boosting a high sensitivity of 27.63% K-1 (at 383K) and a temperature resolution greater than 0.0035K in 293-383K. This work provides a novel bifunctional CsPbBr3 PQDs based sensor for reliable and visual detection of TC concentration and temperature, laying the foundation for the development of high-quality POC sensors with exceptional sensitivity and practicality.