Atomic Alignment in PbS Nanocrystal Superlattices with Compact Inorganic Ligands via Reversible Oriented Attachment of Nanocrystals

TL;DR

This study demonstrates reversible atomic alignment in PbS nanocrystal superlattices using inorganic ligands, revealing thermodynamically stabilized orientational order and enabling dynamic, reconfigurable material structures with potential electronic and optoelectronic applications.

Contribution

It introduces a reversible assembly method for PbS nanocrystal superlattices with atomic-lattice alignment using strongly charged inorganic ligands, advancing reconfigurable nanomaterials.

Findings

Nanocrystals form long-range ordered superlattices with atomic alignment.

Reversible disassembly into colloids is achieved.

Orientational order is stabilized by many-body ion correlations.

Abstract

Nanocrystals (NCs) serve as versatile building blocks for the creation of functional materials, with NC self-assembly offering opportunities to enable novel material properties. Here, we demonstrate that PbS NCs functionalized with strongly negatively charged metal chalcogenide complex (MCC) ligands, such as $Sn_2S_6^{4-}$ and $AsS_4^{3-}$, can self-assemble into all-inorganic superlattices with both long-range superlattice translational and atomic-lattice orientational order. Structural characterizations reveal that the NCs adopt unexpected edge-to-edge alignment, and numerical simulation clarifies that orientational order is thermodynamically stabilized by many-body ion correlations originating from the dense electrolyte. Furthermore, we show that the superlattices of $Sn_2S_6^{4-}$-functionalized PbS NCs can be fully disassembled back into the colloidal state, which is highly unusual for orientationally attached superlattices with atomic-lattice alignment. The reversible oriented attachment of NCs, enabling their dynamic assembly and disassembly into effectively single-crystalline superstructures, offers a pathway toward designing reconfigurable materials with adaptive and controllable electronic and optoelectronic properties.