Cation Exchange on 2-D PbSe Superlattices

Abstract

PbSe quantum dots (QDs) of between 4 – 5 nm in size were synthesised by a heat-up and hot-injection method. These were used to perform oriented attachment whereby the QDs were connected via interatomic bonds to form extended 2-dimentional superlattices. The effect of the initial QD size, heating after attachment, and the use of molecules such as lead (II) oleate and oleic acid, on the resulting superlattice structure was investigated. Cation exchange (CE) was performed on the superlattices, however, the CE process resulted in ~ 90 % of the superlattices washing away. The solid support was coated with a silane molecule resulting in an increased retention of superlattices from 10 % to 27 %. CE reactions on individual PbSe QDs was performed, converting them first to CdSe and then to HgSe.