Multicolored devices fabricated by direct lithography of colloidal nanocrystals

Colloidal nanocrystals (NCs) are interesting as potential active medium for novel nanophotonic and nanoelectronic devices, due to their low fabrication costs and full tunability of their opto-electronic properties. In this work we report a multi step approach for the fabrication of multicolored micro- and nano- displays by localizing NCs through lithographic techniques without recurring to etching processes or surface treatment of the substrate. We demonstrate the possibility to localize different ensembles of emitters on the same substrate by realigned photolithographic steps or mix-and-match electron beam and photolithographic approaches. Moreover, fine tuning of the overall pixel emission is shown by varying the concentration ratio among localized red and green NCs. This technique enables the fabrication of optically pumped colored pixels with very high definition. Our approach combined with advances in NCs-based light emitting diodes technology will enable the electrical injection of advanced micro and nano light sources.