fig2

Figure 2. (A) Absorption and PL spectra of Yb³⁺:CsPbCl₃ NCs post-treated with different amounts of CdCl₂. Time-resolved PL decay curves of the excitons (B) and Yb³⁺ emissions (C), respectively; (D) Average PL lifetimes of the excitons and Yb³⁺ ions extracted from biexponential fitting; (E) PLQYs of the excitonic emission, Yb³⁺ near-infrared emission, and total emission, together with the exciton to Yb³⁺ energy transfer efficiencies (η_ET), for Yb³⁺:CsPbCl₃ NCs treated with different amounts of CdCl₂; (F) Comparison of the average PL lifetimes of the excitons and Yb³⁺ ions, as well as the total PLQYs of Yb³⁺:CsPbCl₃ NCs treated with different metal chlorides (CdCl₂, ZnCl₂, NiCl₂, and CuCl₂). PLQY: Photoluminescence quantum yield; NCs: nanocrystals; PL: photoluminescence.