Emission Fingerprint Relationships of Low‐Level Water in Organic Solvents Based on Ln³⁺‐β‐Diketonate Complexes in Laponite

Detection of low‐content water in organic solvents is highly desirable for a number of chemical industries. However, most of luminescence water detectors reported so far easily generate liquid waste and the luminescence intensity of single emissive transition is susceptible by many factors. Herein a simple and green solid‐state detecting way is proposed to achieve the ratiometric detection of low‐level water in organic solvents based on Eu³⁺, Tb³⁺, and acac co‐doped Laponite (abbreviated as Eu₁Tb₉(acac)_n@Lap). Such a luminescence detector represents excellent fingerprint correlation between water content in solvents and emission intensity ratio (I_Eu/I_Tb), and the variable emissive light colors of Eu₁Tb₉(acac)_n@Lap is observed as water concentration in common organic solvents (MeCN, EtOH, and THF) increases (0%–5% v/v) clearly and directly with the naked eye. The approach should be a very promising strategy to achieve the low‐content water detecting in organic solvents.