For a given doping percentage, larger NCs contain a larger number of electrons (<Nsys>) and a higher electron density (<nsys>) after the synthesis, as compared to smaller NCs. Since the doping percentage is the same for all NCs in a size series, the width of the depletion layer is close to constant but constitutes a different volume fraction for each NC depending upon the diameter of the NC. When electrons are added through chemical doping, larger NCs can accommodate a larger number of electrons per NC (<Ntitr>) in their relatively large depletion volume. However, the electron concentration change in the core (<ntitr>) is lower. Thus, with an increase in the diameter of the NC, <Ntitr> increases but (<ntitr>) decreases (Figure ). Since this trend runs opposite to the trend for (<nsys>), the maximum electron density after chemical doping, (<nmax> = <nsys> + <ntitr>) is approximately constant with size. Further, since smaller NCs having a smaller <nsys> add a correspondingly larger <ntitr>, there is a larger change in total electron density, which leads to larger LSPR shift (equation 1) for smaller NCs than larger NCs having the same Sn doping percentage.