In Situ Quantification of Interactions between Charged Nanorods in a Predefined Potential Energy Landscape.

Quantitative understanding of nanoscale interactions is a prerequisite for harnessing the remarkable collective properties of nanoparticle systems. Here, we report the combined use of liquid-phase transmission electron microscopy and electron beam lithography to elucidate the interactions between charged nanorods in a predefined potential energy landscape. In situ site-selective lift-off of surface-functionalized lithographed gold nanorods is achieved by patterning them with adhesion layer materials that undergo etching at different rates.

The Use of Graphene and Its Derivatives for Liquid-Phase Transmission Electron Microscopy of Radiation-Sensitive Specimens.

One of the key challenges facing liquid-phase transmission electron microscopy (TEM) of biological specimens has been the damaging effects of electron beam irradiation. The strongly ionizing electron beam is known to induce radiolysis of surrounding water molecules, leading to the formation of reactive radical species. In this study, we employ DNA-assembled Au nanoparticle superlattices (DNA-AuNP superlattices) as a model system to demonstrate that graphene and its derivatives can be used to mitigate electron beam-induced damage.

Spiers Memorial Lecture. New tools for observing the growth and assembly of colloidal inorganic nanocrystals.

We present two examples of the use of liquid cells to study colloidal inorganic nanocrystals using in situ transmission electron microscopy. The first uses a liquid cell to quantify the interaction potential between pairs of colloidal nanocrystals, and the second demonstrates direct imaging of nanocrystal growth and structure in the liquid cell.

Interaction Potentials of Anisotropic Nanocrystals from the Trajectory Sampling of Particle Motion using in Situ Liquid Phase Transmission Electron Microscopy.

We demonstrate a generalizable strategy to use the relative trajectories of pairs and groups of nanocrystals, and potentially other nanoscale objects, moving in solution which can now be obtained by in situ liquid phase transmission electron microscopy (TEM) to determine the interaction potentials between nanocrystals. Such nanoscale interactions are crucial for collective behaviors and applications of synthetic nanocrystals and natural biomolecules, but have been very challenging to measure in situ at nanometer or sub-nanometer resolution. Here we use liquid phase TEM to extract the mathematical form of interaction potential between nanocrystals from their sampled trajectories.

Correlating triplet yield, singlet oxygen generation and photochemical stability in polymer/fullerene blend films.

The photostability of two donor polymers, DPP-TT-T and PTB7, is compared in neat films and blend films with PC(71)BM. In both neat and blend films, PTB7 is shown to be relatively unstable. This observation is shown to correlate with transient optical studies of long lived polymer triplets and with molecular probe studies of singlet oxygen yields.