Fig. 4: Charge storage enhancement through depletion layer engineering.
From: Control of electronic band profiles through depletion layer engineering in core–shell nanocrystals
a Upper panel: Photoelectrons stored in the NCs as a function of the shell thickness, showing the \({{{\Delta }}}{{{{N}}}}_{{{{e}}}} \sim {{{{{t}}}}_{{{{s}}}}}^{{{{3}}}}\) trend for values extracted from the empirical multi-layer model (black curve) and the numerical simulations (orange curve). Bottom Panel: Number of electrons extracted via chemical titration using F4TCNQ molecules as a function of \({{{{t}}}}_{{{{s}}}}\). The error bars represent the lower and upper limit of the charges extracted within the uncertainty of the data. b Experimental comparison between the optical response of two samples with same size and doping concentrations but different electronic structure, before (dotted line) and after (solid line) photodoping (homogeneous ITO in blue, core–shell ITO-In2O3 in red). The sensitivity of the LSPR modulation via photodoping is enhanced in the core–shell case. We highlight that the peak position of the LSPR after photodoping blueshifts in the homogeneous case, while it redshifts in the core–shell case indicating that depletion layer modulation is the main process of photodoping (see discussion above).
