(524c) Modulating Electron Transport in PbSe Inorganic Nanocomposites: Doping Through Surface Engineering

In this work we report the use of inorganic matrices to engineer the carrier transport and interparticle spacing for lead selenide (PbSe) nanocrystal array.  Electrically insulating PbSe nanocrystal superlattices are converted into conductive nanocomposites by post assembly ligand exchange of the organic ligands with inorganic chalcogenidometallate clusters (CHAMs) of (N₂H₅)₄Sn₂S₆ / (N₂H₄)_x(N₂H₅)₄Ge₂S₆ or neutral polymorphs of (N₂H₄)₂ZnTe. Thermal annealing or chemical treatment further eliminates the hydrazine/hydrazinium cation and excess chalcogen to give the final inorganic nanocomposites. This work will discuss the fabrication method of defect-free and highly ordered nanocomposite films of PbSe nanocrystals. Our synthesis procedure entails independent processing of nanocrystals and inorganic matrix materials. Thus, it enables more control over the composition of resulting nanocomposites. Interestingly, we demonstrate it is possible to create either n- or p- type thin film transistors of PbSe nanocomposites based upon the choice of the inorganic matrix material (SnS₂ / GeS₂ / (N₂H₄)ZnTe). Our findings suggest a practical route to control doping in semiconductor nanocrystal array of PbSe.