Chloroaurate ions below organic monolayers: Competitive accumulation and gold nanocrystal growth

<div><div><div><p>Covalently bonded organic monolayers play important roles in defining the solution processability, ambient stability, and electronic properties of two-dimensional (2D) materials such as Ge nanosheets (GeNSs); they also hold promise of providing avenues for the fabrication of future generation electronic and optical devices. Functionalization of GeNS normally involves surface moieties linked through covalent Ge−C bonds. In the present contribution we extend the scope of surface linkages to include Si−Ge bonding and present the first demonstration of heteronuclear dehydrocoupling of organosilanes to hydride-terminated GeNSs obtained from the deintercalation and exfoliation of CaGe2. We further exploit this new surface reactivity and demonstrated the preparation of directly bonded silicon quantum dot-Ge nanosheet hybrids.</p></div></div></div>

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Chemical Availability of Bromide Dictates CsPbBr3 Nanocrystal Growth

10.26434/chemrxiv.8081504 ◽

2019 ◽

Author(s):

Je-Ruei Wen ◽

Benjamin Roman ◽

Freddy Rodriguez Ortiz ◽

Noel Mireles Villegas ◽

Nicholas Porcellino ◽

...

Keyword(s):

Reaction Time ◽

Growth Mechanism ◽

Chemical Control ◽

Critical Role ◽

Phase Evolution ◽

Detailed Understanding ◽

Semiconductor Nanocrystal ◽

Nanocrystal Growth ◽

Chemical Availability

Lack of detailed understanding of the growth mechanism of CsPbBr3 nanocrystals has hindered sophisticated morphological and chemical control of this important emerging optoelectronic material. Here, we have elucidated the growth mechanism by slowing the reaction kinetics. When 1-bromohexane is used as an alternative halide source, bromide is slowly released into the reaction mixture, extending the reaction time from ~3 seconds to greater than 20 minutes. This enables us to monitor the phase evolution of products over the course of reaction, revealing that CsBr is the initial species formed, followed by Cs4PbBr6, and finally CsPbBr3. Further, formation of monodisperse CsBr nanocrystals is demonstrated in a bromide-deficient and lead-abundant solution. The CsBr can only be transformed into CsPbBr3 nanocubes if additional bromide is added. Our results indicate a fundamentally different growth mechanism for CsPbBr3 in comparison with more established semiconductor nanocrystal systems and reveal the critical role of the chemical availability of bromide for the growth reactions.<br>

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Multiple electrochemically accessible colour states in surface-confined metal-organic monolayers: Stepwise embedding individual metal centres

Materials Advances ◽

10.1039/d0ma00735h ◽

2021 ◽

Author(s):

Nadia O. Laschuk ◽

Rana Ahmad ◽

Iraklii I. Ebralidze ◽

Jade Poisson ◽

Franco Gaspari ◽

...

Keyword(s):

Iron Complexes ◽

Organic Monolayers ◽

Individual Metal ◽

Surface Enhanced ◽

Metal Organic

Sequential covalent embedding of cobalt, osmium, and iron complexes of 4'-(pyridin-4-yl)-2,2':6',2''-terpyridine to surface-enhanced support pre-functionalized with a templating layer results in hetero-bimetallic (Os-Fe and Co-Fe) and hetero-trimetallic (Co-Os-Fe) monolayer materials....

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