Facet to Facet Linking of Shape Anisotropic Inorganic Nanocrystals with Site Specific and Stoichiometric Control

Abstract

Nonclassical growth mechanisms such as self-assembly and oriented attachment are effective ways to build complex nanostructures from simpler ones. In the latter case, the nanoparticle components are electronically coupled; however, control over the attachment between nanoparticles is highly challenging and generally requires a delicate balance between dipole-, ligand-, and solvent-based interactions. To this end, we perform incomplete cation exchange with Ag (Cu) on CdSe-seeded CdS nanorods and tetrapods to exclusively convert their tips into small AgS (CuS) domains. Selective removal of the ligands from these inorganic domains results in spontaneous, site-specific bridging of the nanoparticles. Using this method, we demonstrate the fabrication of polymer-like linear and branched nanoparticles with enhanced electrical properties, as well as the stoichiometric formation of nanoparticle homo- and heterodimers and tetramers. We show that linked structures can then be completely cation exchanged with Pb to generate PbSe/PbS-based nanostructured photodetector media with enhanced properties.

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

“…The mechanism for linking was previously reported by Sabyasachi et al 5 and will not be described in detail in this work. It is observed that, without the addition of ODPA, no linking takes place as seen in Figure 2(a), in accordance with the view that the addition of ODPA causes the native surface ligands of the Ag 2 S tip to come off.…”

“…We have recently developed a wet-chemical method of covalently joining shape-anisotropic cadmium chalcogenide NCs by introducing a reactive inorganic intermediate through a site-selective nucleation process. The particles are subsequently linked by the spontaneous fusion of the reactive inorganic intermediate domains 5 . Although the technique is still based on an oriented attachment mechanism, there is much less need to consider weak interparticle interactions, thus allowing for more flexibility and control.…”

Low‐Temperature Growth of High‐Quality Ag2HgS2 Crystals for Setup of Weak‐Light UV–Visible–NIR Photodetectors

“…[53] However, it is interesting that the present MSM type photodetectors based on the Ag 2 HgS 2 SCRs show linear responses, and they perform equivalent and high responsivities compared with most high-level van der Waals heterojunction photodetectors. [62][63][64][65] In fact, it is also worth noting that the Ag 2 HgS 2 SCRs photodetectors perform better than the InGaAs photodetectors (PDA20C2, Thorlabs, effective wavelength range between ≈800 and 1700 nm, Responsivity = 1 A W −1 , NEP = 2.2 × 10 −11 W Hz −1/2 ) and PbSe photodetectors (PDA20H, Thorlabs, NEP = 1.5 × 10 −10 W Hz −1/2 ) that have been commercially used. The investigations illustrate that the as-made Ag 2 HgS 2 -based photodetectors with extraordinary performance are highly potential for practical applications, especially in weak light photodetection including infrared regions in the future since Ag 2 HgS 2 is an alternatively promising and qualified candidate due to its intrinsic property and excellent photodetecting behavior.…”

A robust low data solution: Dimension prediction of semiconductor nanorods

“…24 Lastly, aspect ratio is also a key parameter when considering the selfassembly of these nanorods into mesostructures, affecting their usage in optoelectronic device applications. 25,26 Despite the significant improvement in synthesis and application of CdSe/CdS NRs, one major obstacle hindering its development is the laborious and time consuming experimental trial and error optimizations involved due to the complex behavior in the experimental parameter space. During the rod-like shell growth, the core size/amount, precursors amount, ligand type/ratio can impact the dimension of the rod and, in turn, optical properties of NRs.…”