Liquid Cell Transmission Electron Microscopy Study of Platinum Iron Nanocrystal Growth and Shape Evolution

We study solution growth of platinum iron nanocrystals in situ in a liquid cell by using transmission electron microscopy. By varying the oleylamine concentration, we observed that platinum iron nanoparticle growth follows different trajectories with diverse shape evolution. With 20% oleylamine, three stages of growth were observed: (i) nucleation and growth of platinum iron nanoparticles in the precursor solution; (ii) nanowire formation by shape-directed nanoparticle attachment; and (iii) breakdown or shrinkage of the nanowires into individual nanoparticles with large size distribution. With 30% oleylamine, formation of platinum iron nanowires similar to that with 20% oleylamine was observed. However, those nanowires do not break down or shrink, which suggests that nanowires are stabilized by oleylamine as surfactant binding on the surface. With 50% oleylamine, after the individual nanoparticles are formed, they do not merge into nanowires. The shape of the nanoparticle is strongly influenced by the neighboring nanoparticles due to stereo-hindrance effects. Real-time observation of the dynamic growth process sheds light on the controllable synthesis of nanomaterials

In Situ Observation of Oscillatory Growth of Bismuth Nanoparticles

We study the growth of Bi nanoparticles in an engineered precursor-scarce environment in a liquid cell at an elevated temperature (180 °C) using transmission electron microscopy. Observation reveals dynamics of oscillatory growth of individual nanoparticles, pairwise Ostwald ripening and anti-Ostwald ripening and a global collective oscillation. The experimental results suggest a mass-transport zone is present around each particle, which couples to the observed growth kinetics. This study shed light on a new route for system engineering to reverse particle coursing by Ostwald ripening

Liquid Cell Transmission Electron Microscopy Study of Platinum Iron Nanocrystal Growth and Shape Evolution

We study solution growth of platinum iron nanocrystals in situ in a liquid cell by using transmission electron microscopy. By varying the oleylamine concentration, we observed that platinum iron nanoparticle growth follows different trajectories with diverse shape evolution. With 20% oleylamine, three stages of growth were observed: (i) nucleation and growth of platinum iron nanoparticles in the precursor solution; (ii) nanowire formation by shape-directed nanoparticle attachment; and (iii) breakdown or shrinkage of the nanowires into individual nanoparticles with large size distribution. With 30% oleylamine, formation of platinum iron nanowires similar to that with 20% oleylamine was observed. However, those nanowires do not break down or shrink, which suggests that nanowires are stabilized by oleylamine as surfactant binding on the surface. With 50% oleylamine, after the individual nanoparticles are formed, they do not merge into nanowires. The shape of the nanoparticle is strongly influenced by the neighboring nanoparticles due to stereo-hindrance effects. Real-time observation of the dynamic growth process sheds light on the controllable synthesis of nanomaterials

Liquid Cell Transmission Electron Microscopy Study of Platinum Iron Nanocrystal Growth and Shape Evolution

We study solution growth of platinum iron nanocrystals in situ in a liquid cell by using transmission electron microscopy. By varying the oleylamine concentration, we observed that platinum iron nanoparticle growth follows different trajectories with diverse shape evolution. With 20% oleylamine, three stages of growth were observed: (i) nucleation and growth of platinum iron nanoparticles in the precursor solution; (ii) nanowire formation by shape-directed nanoparticle attachment; and (iii) breakdown or shrinkage of the nanowires into individual nanoparticles with large size distribution. With 30% oleylamine, formation of platinum iron nanowires similar to that with 20% oleylamine was observed. However, those nanowires do not break down or shrink, which suggests that nanowires are stabilized by oleylamine as surfactant binding on the surface. With 50% oleylamine, after the individual nanoparticles are formed, they do not merge into nanowires. The shape of the nanoparticle is strongly influenced by the neighboring nanoparticles due to stereo-hindrance effects. Real-time observation of the dynamic growth process sheds light on the controllable synthesis of nanomaterials

In Situ Observation of Oscillatory Growth of Bismuth Nanoparticles

We study the growth of Bi nanoparticles in an engineered precursor-scarce environment in a liquid cell at an elevated temperature (180 °C) using transmission electron microscopy. Observation reveals dynamics of oscillatory growth of individual nanoparticles, pairwise Ostwald ripening and anti-Ostwald ripening and a global collective oscillation. The experimental results suggest a mass-transport zone is present around each particle, which couples to the observed growth kinetics. This study shed light on a new route for system engineering to reverse particle coursing by Ostwald ripening

In Situ Observation of Oscillatory Growth of Bismuth Nanoparticles

We study the growth of Bi nanoparticles in an engineered precursor-scarce environment in a liquid cell at an elevated temperature (180 °C) using transmission electron microscopy. Observation reveals dynamics of oscillatory growth of individual nanoparticles, pairwise Ostwald ripening and anti-Ostwald ripening and a global collective oscillation. The experimental results suggest a mass-transport zone is present around each particle, which couples to the observed growth kinetics. This study shed light on a new route for system engineering to reverse particle coursing by Ostwald ripening

Electron Beam Manipulation of Nanoparticles

We report on electron beam manipulation and simultaneous transmission electron microscopy imaging of gold nanoparticle movements in an environmental cell. Nanoparticles are trapped with the beam and move dynamically toward the location with higher electron density. Their global movements follow the beam positions. Analysis on the trajectories of nanoparticle movements inside the beam reveals a trapping force in the piconewton range at the electron density gradient of 10³–10⁴ (e·nm^–2·s^–1)·nm^–1. Multiple nanoparticles can also be trapped with the beam. By rapidly converging the beam, we further can “collect” nanoparticles on the membrane surface and assemble them into a cluster

Electron Beam Manipulation of Nanoparticles

We report on electron beam manipulation and simultaneous transmission electron microscopy imaging of gold nanoparticle movements in an environmental cell. Nanoparticles are trapped with the beam and move dynamically toward the location with higher electron density. Their global movements follow the beam positions. Analysis on the trajectories of nanoparticle movements inside the beam reveals a trapping force in the piconewton range at the electron density gradient of 10³–10⁴ (e·nm^–2·s^–1)·nm^–1. Multiple nanoparticles can also be trapped with the beam. By rapidly converging the beam, we further can “collect” nanoparticles on the membrane surface and assemble them into a cluster

Electron Beam Manipulation of Nanoparticles

We report on electron beam manipulation and simultaneous transmission electron microscopy imaging of gold nanoparticle movements in an environmental cell. Nanoparticles are trapped with the beam and move dynamically toward the location with higher electron density. Their global movements follow the beam positions. Analysis on the trajectories of nanoparticle movements inside the beam reveals a trapping force in the piconewton range at the electron density gradient of 10³–10⁴ (e·nm^–2·s^–1)·nm^–1. Multiple nanoparticles can also be trapped with the beam. By rapidly converging the beam, we further can “collect” nanoparticles on the membrane surface and assemble them into a cluster

Electron Beam Manipulation of Nanoparticles

We report on electron beam manipulation and simultaneous transmission electron microscopy imaging of gold nanoparticle movements in an environmental cell. Nanoparticles are trapped with the beam and move dynamically toward the location with higher electron density. Their global movements follow the beam positions. Analysis on the trajectories of nanoparticle movements inside the beam reveals a trapping force in the piconewton range at the electron density gradient of 10³–10⁴ (e·nm^–2·s^–1)·nm^–1. Multiple nanoparticles can also be trapped with the beam. By rapidly converging the beam, we further can “collect” nanoparticles on the membrane surface and assemble them into a cluster