Kinetics‐Tunable Hydrochromic Luminescence Switching in Rb3TbF6:Eu3+ Perovskite

Abstract

AbstractHydrochromic luminescent materials that are responsive to water or moisture have attracted considerable attention owing to their extensive use in sensing and information security. However, fine‐tuning hydrochromic response to water content remains unfulfilled research, posing constraints in the widespread application of hydrochromic luminescence. This study reports a 0D Rb3TbF6 perovskite with highly controllable hydrochromic characteristics. The Rb3TbF6 crystals exhibit a distinct hydrochromic luminescence switching after B‐site doping with Eu3+, stemming from Rb3TbF6 to Rb2TbF5 transformation that triggers intra‐crystal Tb3+‐to‐Eu3+ energy transfer. Through A‐site alkaline metal alloying, the sensitivity of the perovskite to water stimuli is precisely tuned, rendering distinct responses over a wide range of humidity conditions (RH: 1–90% RH) and water levels (v/v: 0.5–55%). As an added benefit, the hydrochromic crystals also show excellent repeatability and photothermal stability. These advances on hydrochromic materials provide exciting opportunities in water detection, humidity sensing, and multi‐level information encryption.