Evolution of Self-Assembled ZnTe Magic-Sized Nanoclusters

Abstract

Three families of ZnTe magic-sized nanoclusters (MSNCs) were obtained exclusively using polytellurides as a tellurium precursor in a one-pot reaction by simply varying the reaction temperature and time only. Different ZnTe MSNCs exhibit different self-assembling or aggregation behavior, owing to their different structure, cluster size, and dipole-dipole interactions. The smallest family of ZnTe MSNCs (F323) does not reveal a crystalline structure and as a result assembles into lamellar triangle plates. Continuous heating of as synthesized ZnTe F323 assemblies resulted in the formation of ZnTe F398 MSNCs with wurzite structure and concomitant transformation into lamellar rectangle assemblies with the organization of nanoclusters along the ⟨002⟩ direction. Further annealing of ZnTe F398 assembled lamellar rectangles leads to full organization of MSNCs in all directions and formation of larger ZnTe F444 NCs that spontaneously form ultrathin nanowires following an oriented attachment mechanism. The key step in control over the size distribution of ZnTe ultrathin nanowires is, in fact, the growth mechanism of ZnTe F398 MSNCs; namely, the step growth mechanism enables formation of more uniform nanowires compared to those obtained by continuous growth mechanism. High yield of ZnTe nanowires is achieved as a result of the wurzite structure of F398 precursor. Transient absorption (TA) measurements show that all three families possess ultrafast dynamics of photogenerated electrons, despite their different crystalline structures.

Two-Dimensional Colloidal Nanocrystals

“…129 These quantum wires exhibit similar optical properties as quantum platelets with well defined absorption peaks and unusually thin transitions. Wurtzite quantum platelets and zinc-blende nanoplatelets exhibit the same optical features which will be treated in section 3.2.…”

Templated Growth of InP Nanocrystals with a Polytwistane Structure

“…The existence of non‐classical cluster intermediates during crystal growth has been shown to have profound implications on the growth kinetics of NCs . These locally stable intermediates, so called magic‐sized clusters, are characterized by their molecule‐like monodispersity, unusual stability, and in many cases their ability to seed the growth of kinetically accessible nanomaterial morphologies such as nanobelts, platelets, and pyramids . This last feature has made magic‐sized clusters intriguing synthons for templated nanomaterial synthesis and suggests that exploiting their unique structural properties can facilitate the synthesis of new nanoscale phases .…”

Templated Growth of InP Nanocrystals with a Polytwistane Structure

“…Thea bility to define structure at the nascent stage of nanocrystal (NC) nucleation has enabled the synthesis of awide variety of non-thermodynamic structures,including Al, Ge,and Au clusters, [1][2][3][4][5] metal chalcogenide superlattices, [6][7][8][9] allotropic phases such as e-Co, [10] and molecule-like crystals of InP and CdSe, [11][12][13][14] many of which exhibit unique surface chemistry and optical properties,a nd all of which redefine the classical ideas of material phase and crystal synthesis.Controlling the synthesis of these non-thermodynamic materials using soft-chemical methods presents ap articular challenge.E fforts in the field of semiconductor NC synthesis have revealed colloidal routes to,for example,new allotropes of Si [15] as well as metastable phases of CuInSe 2 [16] and SnS. Thea bility to define structure at the nascent stage of nanocrystal (NC) nucleation has enabled the synthesis of awide variety of non-thermodynamic structures,including Al, Ge,and Au clusters, [1][2][3][4][5] metal chalcogenide superlattices, [6][7][8][9] allotropic phases such as e-Co, [10] and molecule-like crystals of InP and CdSe, [11][12][13][14] many of which exhibit unique surface chemistry and optical properties,a nd all of which redefine the classical ideas of material phase and crystal synthesis.Controlling the synthesis of these non-thermodynamic materials using soft-chemical methods presents ap articular challenge.E fforts in the field of semiconductor NC synthesis have revealed colloidal routes to,for example,new allotropes of Si [15] as well as metastable phases of CuInSe 2 [16] and SnS.…”

“…Growing evidence suggests that classical mechanisms are in many cases insufficient to explain the formation of semiconductor NCs. [7,9,14] This last feature has made magic-sized clusters intriguing synthons for templated nanomaterial synthesis and suggests that exploiting their unique structural properties can facilitate the synthesis of new nanoscale phases. [18,21,22] These locally stable intermediates,s oc alled magic-sized clusters,are characterized by their molecule-like monodispersity,u nusual stability,a nd in many cases their ability to seed the growth of kinetically accessible nanomaterial morphologies such as nanobelts,p latelets,a nd pyramids.…”