Fig. 2. (a) The digital photos of PLNPs powder (left), and 5 s after stopping UV irradiation (right); (b) TEM image of PLNPs; (c) excitation and emission spectra of the PLNPs; (d) time-dependent PL intensity of PLNPs (1 mg mL−1) without further excitation after direct exposure under a UV lamp for 10 min; (e) PL responses of the PLNPs in different pH solutions; (f) PL responses of the PLNPs in different media. The concentrations of ions: 10 μM.
