Figure 7.
Characterization of Pb4S3I2 and Pb3S2Cl2 NCs. TEM images of (a) Pb4S3I2 and (b) Pb3S2Cl2 NCs. (c) XRPD patterns of the three NC samples (Pb4S3I2, Pb4S3Br2, Pb3S2Cl2) and related Rietveld fits (Tables S3, S4, and S9). The red asterisks in the Pb4S3I2 pattern highlight the peaks coming from an impurity, most likely PbI2 nanosheets or flakes. (d) Optical absorption spectra of the three samples. The almost perfect overlap suggests that, despite the different composition, stoichiometry, and structure, the halides play a very minor role in the optical properties of this class of nanomaterials. The only appreciable trend is visible at the onset of the spectrum (inset).