Figure 3.

Absorption spectra of template Cu_2–xSe NCs (blue lines) and product CdSe NCs (red lines) and CuInSe₂ NCs (brown lines) obtained after CE reactions (Cu⁺ for Cd²⁺, and partial, self-limited Cu⁺ for In³⁺, respectively). The spectra were normalized at 400 nm. TEM images of the samples used to acquire the optical spectra are shown below (Figure 4). (A) Absorption spectra of quantum dots of different compositions. (B) Absorption spectra of thick nanoplatelets. Optical spectra of thinner (l ≤ 4.2 nm) CdSe nanoplatelets displaying PL are shown in Figure S11. (C) Absorption spectra of ultrathin nanosheets.