CsPbBr₃ Perovskite–Coated Paper Substrate for the Cost‐Effective Detection of Fluoride, Chloride, and Iodide Ions in Water

Abstract

Developing a simple and cost‐effective substrate for the detection of the halide ions present in water is extremely important due to their adverse effects at higher concentrations. A good substrate should behave differently in the presence of different halide ions. Herein, a CsPbBr3‐coated paper substrate is used for the detection of fluoride, chloride, and iodide ions. As a result of the fast anion exchange reactions, in the presence of each halide ion, the CsPbBr3‐coated paper shows different emission behaviors. The presence of chloride and iodide ions results in blueshifted and redshifted absorption and emission, respectively. In the presence of fluoride ions, anion exchange followed by decomposition of the perovskite nanocrystal is observed. The anion exchange reactions of CsPbBr3 perovskites are faster than the moisture‐induced decomposition, which enables the detection of micromolar concentrations of fluoride, chloride, and iodide ions in water.

Anion Exchange in Lead Halide Perovskites: An Overview

“…[ 51 ] In an earlier work, we have shown the detection of chloride, iodide, and fluoride ions in water samples, using lead halide perovskites coated Whatman 40 filter paper as the substrate. [ 52 ] Herein, we have used dip coating method for the fabrication of the perovskite‐coated paper substrates. [ 52 ] Further, with the help of a 352 nm UV lamp, we could detect the presence of halide ions even at the concentration range of micromoles per liter ( Figure 4 ).…”

“…[ 52 ] Herein, we have used dip coating method for the fabrication of the perovskite‐coated paper substrates. [ 52 ] Further, with the help of a 352 nm UV lamp, we could detect the presence of halide ions even at the concentration range of micromoles per liter ( Figure 4 ). [ 52 ] On spotting chloride ion containing water on CsPbBr 3 coated paper substrate, the emission showed a shift from green to violet blue (Figure 4B), whereas, upon spotting iodide containing water, the emission turned red (Figure 4C).…”

“…[ 52 ] Further, with the help of a 352 nm UV lamp, we could detect the presence of halide ions even at the concentration range of micromoles per liter ( Figure 4 ). [ 52 ] On spotting chloride ion containing water on CsPbBr 3 coated paper substrate, the emission showed a shift from green to violet blue (Figure 4B), whereas, upon spotting iodide containing water, the emission turned red (Figure 4C). [ 52 ] At the same time, in the presence of fluoride ions, the decomposition of the CsPbBr 3 perovskite was observed.…”

“…[ 52 ] On spotting chloride ion containing water on CsPbBr 3 coated paper substrate, the emission showed a shift from green to violet blue (Figure 4B), whereas, upon spotting iodide containing water, the emission turned red (Figure 4C). [ 52 ] At the same time, in the presence of fluoride ions, the decomposition of the CsPbBr 3 perovskite was observed. [ 52 ] Thus, under UV light, the fluoride spotted part appeared dark as shown in Figure 4D.…”

“…[ 52 ] At the same time, in the presence of fluoride ions, the decomposition of the CsPbBr 3 perovskite was observed. [ 52 ] Thus, under UV light, the fluoride spotted part appeared dark as shown in Figure 4D. [ 52 ] A control experiment was conducted by spotting deionized water over perovskite coated paper and showed no change in the emission properties of CsPbBr 3 perovskite (Figure 4A).…”