A multi-stimuli-responsive CsPbBr3@PL-MOF functional anti-counterfeiting material.

A new composite material CsPbBr3@HPU-22 was prepared by using {[Zn2(ADDA)2(DMF)(H2O)2]·(DMF)}n (HPU-22) as a carrier to encapsulate CsPbBr3 in channels. The obtained composite material has high sensitivity to water. Under the stimulation of a humid environment or water vapor, the color of the CsPbBr3@HPU-22 product can be seen to turn from yellow to white. In addition, it is necessary to note that the changed color could recover after drying. A study of the mechanism demonstrated that the inter-conversion between CsPbBr3 and CsPb2Br5 is the major reason for this reversible color change during the wetting and drying process. In addition, CsPbBr3@HPU-22 also exhibited high sensitivity to acid–base gases, accompanied by a change in fluorescence color under UV light. The evidence showed that the protonation of DMF molecules might result in the reversible response of CsPbBr3@HPU-22 to acid–base gases. Therefore, the multi-response to water and acid–base gas stimulation gives the CsPbBr3@HPU-22 applications in the field of high-level anti-counterfeiting. [ABSTRACT FROM AUTHOR]