fig3

Figure 3. (A-C) PL spectra of untreated and CdCl₂-treated Yb³⁺:CsPbCl₃ NC films without encapsulation under continuous UV irradiation for different durations, along with the evolution of integrated total PL intensity versus irradiation time (normalized to unirradiated intensity); (D and E) Temperature-dependent PL spectra of untreated and CdCl₂-treated Yb³⁺:CsPbCl₃ NC films measured over the temperature range of 80-360 K; (F and G) Temperature-dependent integrated PL intensities of the Yb³⁺ emission, normalized to the emission intensity at 80 K; The solid lines represent fits to the Arrhenius equation; (H) Schematic illustration of the emission mechanism in Yb³⁺:CsPbCl₃ NCs before and after CdCl₂ treatment. PL: Photoluminescence; NC: nanocrystal; UV: ultraviolet.