Thickness-Controlled Quasi-Two-Dimensional Colloidal PbSe Nanoplatelets
journal contributionposted on 18.01.2017, 00:00 by Weon-kyu Koh, Naveen K. Dandu, Andrew F. Fidler, Victor I. Klimov, Jeffrey M. Pietryga, Svetlana V. Kilina
We demonstrate controlled synthesis of discrete two-dimensional (2D) PbSe nanoplatelets (NPLs), with measurable photoluminescence, via oriented attachment directed by quantum dot (QD) surface chemistry. Halide passivation is critical to the growth of these (100) face-dominated NPLs, as corroborated by density functional theory studies. PbCl2 moieties attached to the (111) and (110) of small nanocrystals form interparticle bridges, aligning the QDs and leading to attachment. We find that a 2D bridging network is energetically favored over a 3D network, driving the formation of NPLs. Although PbI2 does not support bridging, its presence destabilizes the large (100) faces of NPLs, providing means for tuning NPL thickness. Spectroscopic analysis confirms the predicted role of thickness-dependent quantum confinement on the NPL band gap.
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PbCl 2 moietiesnanocrystals form interparticle bridgessurface chemistryPbI 2Halide passivationquantum dottheory studiesNPL thicknessSpectroscopic analysis3 D networkthickness-dependent quantum confinement2 DThickness-Controlled Quasi-Two-Dimensional Colloidal PbSe NanoplateletsQDNPL band gapPbSe nanoplatelets