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Revealing the Cluster‐Cloud and Its Role in Nanocrystallization
Author(s) -
Jin Biao,
Wang Yanming,
Liu Zhaoming,
FranceLanord Arthur,
Grossman Jeffrey C.,
Jin Chuanhong,
Tang Ruikang
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201808225
Subject(s) - nucleation , cluster (spacecraft) , crystallization , materials science , chemical physics , particle (ecology) , crystallinity , supersaturation , nanoparticle , nanocrystal , phase (matter) , transmission electron microscopy , nanotechnology , crystal (programming language) , crystallography , chemical engineering , thermodynamics , chemistry , physics , oceanography , computer science , engineering , composite material , programming language , geology , organic chemistry
Elucidating the early stages of crystallization from supersaturated solutions is of critical importance, but remains a great challenge. An in situ liquid cell transmission electron microscopy study reveals an intermediate state of condensed atomic clusters during Pd and Au crystallizations, which is named a “cluster‐cloud.” It is found that nucleation is initiated by the collapse of a cluster‐cloud, first forming a nanoparticle. The subsequent particle maturation proceeds via multiple out‐and‐in relaxations of the cluster‐cloud to improve crystallinity: from a poorly crystallized phase, the particle evolves into a well‐defined single‐crystal phase. Both experimental investigations and atomistic simulations suggest that the cluster‐cloud‐mediated nanocrystallization involves an order–disorder phase separation and reconstruction, which is energetically favored compared to local rearrangements within the particle. This finding grants new insights into nanocrystallization mechanisms, and provides useful information for the improvement of synthesis pathways of nanocrystals.