3D structure of individual nanocrystals in solution by electron microscopy

Abstract

Abstract:Understanding structural details of colloidal nanoparticles is required to bridge our knowledge about their synthesis, growth mechanisms, and physical properties. We introduce a method for determining 3D structures of individual nanoparticles in solution.We combine a graphene liquid cell, high-resolution transmission electron microscopy, a direct electron detector, and an algorithm for single-particle 3D reconstruction originally developed for analysis of biological molecules to produce two near-atomic resolution 3D structures of individual Pt nanocrystals. Since our method derives the 3D structure from images of individual nanoparticles rotating freely in solution, it enables the analysis of heterogeneous populations of potentially unordered nanoparticles that are synthesized in solution, thereby providing a means to understand the structure and stability of defects at the nanoscale. Main Text:Colloidal nanoparticles are clusters of hundreds to thousands of inorganic atoms typically surrounded by organic ligands that stabilize them in solution. The atomic arrangement of colloidal nanoparticles determines their chemical and physical properties, which are distinct from bulk materials and can be exploited for many applications in biological imaging, renewable energy, catalysis, and more. The 3D atomic arrangement on the surface and in the core of a nanocrystal influences the electronic structure, which affects how the nanocrystal functions in catalysis or how it interacts with other components at the atomic scale (1). Introduction of atomic dopants, surface adatoms, defects, and grain boundaries alters the chemical properties of nanocrystals (2). Ensembles of synthesized nanocrystals in solution are structurally inhomogeneous due to the stochastic nature of nanocrystal nucleation and growth (3,4). Therefore, a method for determination of the 3D atomic arrangement of individual unique nanoparticles in solution is needed. 3Electron tomography is routinely used for 3D analysis of materials (5-9). This method cannot be applied to individual particles in a liquid because it relies on acquisition of images of a single object at many different tilt angles over 2 to 5 hours, assuming the object is static during the entire acquisition. Single particle cryo-electron microscopy (cryo-EM) is a common method for the determination of 3D structures in biological sciences. The average 3D Coulomb potential map (density) of a protein is reconstructed from tens of thousands of TEM images of randomly oriented copies of the same protein embedded in vitreous ice (10). The unknown 3D projection angles of the images are determined by computational methods (11). Single-particle cryo-EM has succeeded in reconstructing biological molecules with nearly 3 Å resolution (10, 12). A similar approach was recently applied to reconstruct the atomic structure of homogeneous ultrasmall gold clusters (13). However, the single-particle method is not readily applicable to 3D reconstruction of colloidal nanoparticles due to their intrinsic struc...

Revealing the Phenomena of Heat and Photon Energy on Dealing Matter at Atomic level

“…In this context, structural design is crucial in targeting their specific application and many studies are now targeting and exploring structure either standalone or in relation to other fields of science [28][29][30][31][32][33][34][35][36][37]. Our several investigations discuss that structural motifs are owing to dynamics of the process arisen by characteristics photons and field forces [16][17][18][19][20][21][22][23][24] where it is proven experimentally in one of the study given elsewhere [18].…”

Revealing the Phenomena of Heat and Photon Energy on Dealing Matter at Atomic level

“…The set modalities of all sorts of photons depend on the origin of their generation establishing roles set by the manufacturer when they deal to suitable matter. In this context, structural design is crucial in targeting their specific application and many studies are now targeting and exploring structure either which standalone or in relation to other fields of science [29][30][31][32][33][34][35][36][37][38]. However, it has been disclosed elsewhere under original line of experiments that all structural motifs are owing to a force and energy [18] but also in semi-metallic materials [21,39].…”

Revealing the Phenomena of Heat and Photon Energy on Dealing Matter at Atomic Level

“…In this context, structural design is crucial in targeting their specific application and many studies are now targeting and exploring structure either which standalone or in relation to other fields of science [28][29][30][31][32][33][34][35][36][37]. However, it has been disclosed elsewhere under original line of experiments that all structural motifs are owing to a forcing energydirected phenomenon and a force-directed phenomenon not only in metallic colloids [18] but also in semi-metallic materials [21,38].…”