Tetraphenylporphyrin-modified perovskite nanocrystals enable ratiometric fluorescent determination of sulfide ion in water samples

A simple and feasible approach was constructed for preparation of all inorganic cesium lead bromide perovskite nanocrystals (CsPbBr 3 NCs) modified with tetraphenylporphyrin tetrasulfonic acid (TPPS). The CsPbBr 3 /TPPS nanocomposite has good water stability and exhibits a dual-emission property. Adopting the CsPbBr 3 /TPPS nanocomposite as a nanoprobe, a rapid, selective and sensitive ratiometric fluorescent method was developed for determination of sulfide ion. When sulfide ion was added into the CsPbBr 3 /TPPS nanocomposite, the bright green fluorescence of CsPbBr 3 NCs at 520 nm was sharply quenched, whereas the red fluorescence of TPPS at 650 nm was hardly influenced. The quenching is possibly attributed to destruction of CsPbBr 3 NCs via the formation of more stable PbS. This nanoprobe can determine sulfide ion over the range of 0.2–15.0 nmol·L −1 with a detection limit as low as 0.05 nmol·L −1 . The relative standard deviation is 3.3% at 10.0 nmol·L −1 concentration level ( n  = 11). Sulfide ion content was successfully determined in different water samples by this nanoprobe. Graphical abstract