The
combination of the two luminous substances to prepare a multifunctional
gel film brings the unexpected pH response properties in the pH range of
sweat. Weakly acidic sweat can induce a decrease in the red fluorescence
of MOF in the composite gel film, forcing the blue fluorescence of BDCZ
to highlight, resulting in a red-blue transformation of the functional
gel film visible to the naked eye. Besides sweat can promote the
phosphorescence of DBCZ. Based on these, a dual-mode sweat pH sensor and
sweat-based anti-counterfeiting can be designed (Figure 1b).
Properties of Y-TCPP/DBCZ PVA composite film
According to the previous reports, the fluorescence intensity of Y-TCPP
MOF increases with the increase of pH from
6-12.[27] Although these properties are still
maintained in the composite film, there have no responsive
photoluminescent property in the pH range of sweat. Actually, this
excellent alkali stimulation responsive luminescence performance of MOF
provides an excellent platform for our composite luminescent materials.