We find that the PL quantum yield (QY) increases from 61 % for the native NCs to a maximum of 73 % upon addition of DCzGPC. Further increase of the ligand concentration reduces the PLQY to 61 % (Fig. ). This finding further strengthens the conclusion of a substantial interaction between the NCs and the novel ligand. . Minor variations in the results could stem from using different substrates , yet earlier measurements conducted on the same gold-coated substrate with CsPbBrI2 showed strong consistency. We find an ionization energy (IE) of 5.75 eV for the native particles and 5.9 eV for the pure DCzGPC ligand. The IE of the ligand-exchanged NCs ranges between 5.78 eV and 5.9 eV, indicating that states of the nanoparticle core contribute to valence band / 1Sh. Also, for the NCs exchanged with DCzGPC the VBM shifts towards higher E-EF values, and we find an enhanced density of states near the VBM while the work function after ligand exchange is nearly unaffected. The measured VBM shift is higher, (220 meV) than the observed hypsochromic shift (120 meV), indicating that the DCzGPC ligand also affects the position of the conduction band minimum. We note that both the shape and energetic position of the Pb4f core level spectra is almost identical for native and ligand-exchanged NCs (Fig. ),