Doping as Strategy to Tune Color of 2D colloidal Nanoplatelets.

Among colloidal nanocrystals, 2D nanoplatelets (NPL) made of II-VI compounds, appear as a special class of emitters with especially narrow photoluminescence signal. However the PL signal in the case of NPL is only tunable by discrete step. Here we demonstrate that doping is a viable path to finely tune the color of this NPL from green to red, making them extremely interesting as phosphor for wide gamut display. In addition using a combination of luminescence spectroscopy, tight binding simulation, transport and photoemission, we provide a consistent picture for the Ag+ doped CdSe NPL. The Ag activated state is strongly bound and located 340 meV above the valence band of the bulk material. The Ag dopant induces a relative shift of the Fermi level toward the valence band by up to 400 meV but preserve the n-type nature of the material.