Ligands as a universal molecular toolkit in synthesis and assembly of semiconductor nanocrystals

Abstract

The multiple ligands with different functionalities enable atomic-precision control of NCs morphology and subtle inter-NC interactions, which paves the way for novel optoelectronic applications.

The role of organic ligand shell structures in colloidal nanocrystal synthesis

“…Their colloidal nature allows them to be dispersed into solvents for optical studies, which include single-particle measurements 7,8 and assemblies of these materials can be created to investigate collective effects and their use as artificial atoms 9,10 .Fundamentally, most colloidal nanocrystals are composites that consist of an inorganic core and an organic ligand shell. This organic ligand shell enables colloidal stability in solvents 11,12 , prevents inorganic cores from fusing 10,13 , passivates undercoordinated atoms that lead to exciton traps in quantum dots [14][15][16][17] , acts as soft matter in the assembly of artificial solids 9,10,18,19 and provides a platform for the modification of inorganic cores 15,17,20 . Beyond contributing to colloidal nanocrystals properties, they are essential in synthesis.Organic ligands mediate growth by binding to growing nanocrystal surfaces as a surfactant.…”

“…Beyond contributing to colloidal nanocrystals properties, they are essential in synthesis.Organic ligands mediate growth by binding to growing nanocrystal surfaces as a surfactant. The group that binds to the nanocrystal surface is referred to as the head group, and the rest of the capping ligand is referred to as the tail group 1,19,21 . Typically, in hydrophobic environments, when growth is terminated by the exhaustion of precursors or reaction quenching, these ligands form an organic shell around each nanocrystal, in which the head groups face into the nanocrystal and the organic tail groups face outward.…”

“…Typically, in hydrophobic environments, when growth is terminated by the exhaustion of precursors or reaction quenching, these ligands form an organic shell around each nanocrystal, in which the head groups face into the nanocrystal and the organic tail groups face outward. The nature of the ligands dictates the inorganic nanocrystal surface structure 11,19,21,22 , and has been designed to promote surfaces that minimize electronic trap states in quantum dots 15,17,23,24 . A variety of head groups are used to terminate colloidal nanocrystal surfaces, such as carboxylates, amines, phosphonates, thiols and halides, and often a mixture of capping groups is used [15][16][17]20,[25][26][27][28][29][30][31][32] .…”

Bridging electrocatalyst and cocatalyst studies for solar hydrogen production via water splitting

“…76,115 To realize such site-specic CC deposition in other loading methods, exploiting the preferential adsorption of surfactants on different crystal planes of PCs could be useful. 172 The surfactants on CC precursor complex or NP surface have functional groups that could interact with coordinatively unsaturated atoms on the PC surface via dynamic adsorption and desorption. Again, the distinct atomic arrangement on the crystal facets of PCs might affect the binding affinities of incoming functional groups.…”

Thermomechanically controlled fluorescence anisotropy in thin films of InP/ZnS quantum dots

“…25,26 An elegant way to achieve structurally anisotropic thin films is by selective adsorption of ligands on different crystallographic facets of quasi-isotropic QDs, which results in an anisotropic organic shell of the nanocrystals, and translates to the anisotropic distribution of QDs in space. [27][28][29] However, besides few sparse examples, 30,31 most anisotropic and quasi-isotropic QDs SLs are static, with restricted tunability of structure and optical characteristics of the materials. In this context, hybrid materials comprising QDs and liquid crystals (QDs/LC) are particularly appealing since they benefit from the soft, ordered, and responsive character of mesogens, allowing to drive the organization/orientation of assemblies of QDs and enabling the formation of macroscopically (devicescale) ordered systems.…”