Colorimetric paper test strips based on cesium lead bromide perovskite nanocrystals for rapid detection of ciprofloxacin hydrochloride.

The detection of drugs containing hydrochloric salt with conventional methods is time consuming and expensive. In this work, upon exposure to ciprofloxacin hydrochloride at different concentrations, the emission from CsPbBr 3 NCs shifts to the blue from 513 nm to 442 nm. CsPbBr (3- x ) Cl x NCs are formed by the ion exchange and substitution of Br - and Cl - ions from surface to core of NCs. The first-principles calculations suggest that the substitution of Br - by Cl - ions plays a critical role in the tuning of the energy bandgap. The color of paper test strips changes immediately after exposure to different Ciproxan solutions. We propose that this rapid and portable method has a high potential application in other chloride salts for food safety.