Optical and structural properties of different thicknesses
of CsPbBr3 NPLs and the exchanged CsPbCl3 and
CsPbI3 NPLs. (A–C) Three different thicknesses,
with (A) 5 ML emitting
at 2.70 eV, Stoke shift (Ss) = 0.11 eV, and fwhm = 0.11 eV; (B) 4
ML emitting at 2.76 eV, Ss = 0.12 eV, and fwhm = 0.17 eV; and (C)
3 ML emitting at 2.83 eV, Ss = 0.11 eV, and fwhm = 0.09 eV. (D,E)
TEM and HRTEM image of 3 ML thick sample indicated a thickness of
1.8 nm. (F) Fine-tuning the PL of CsPbBr3 NPLs with anion-exchange
reactions to CsPbCl3 and CsPbI3. Scale bar corresponds
to 50 nm in D, and 2 nm in E.