The growth of silver shells on gold nanorods is investigated by in situ liquid cell transmission electron microscopy using an advanced liquid cell architecture. The design is based on microwells in which the liquid is confined between a thin Si 3 N 4 membrane on one side and a few-layer graphene cap on the other side. A well-defined specimen thickness and an ultraflat cell top allow for the application of high-resolution TEM and the application of analytical TEM techniques on the same sample. The combination of high-resolution data with chemical information is validated by radically new insights into the growth of silver shells on cetrimonium bromide stabilized gold nanorods. It is shown that silver bromide particles already formed in the stock solution play an important role in the exchange of silver ions. The Ag shell growth can be directly correlated with the layer-by-layer dissolution of AgBr nanocrystals, which can be controlled by the electron flux density via distinctly generated chemical species in the solvent. The derived model framework is confirmed by in situ UV−vis absorption spectroscopy evaluating the blue shift in the longitudinal surface plasmon resonance of anisotropic NRs in a complementary batch experiment.

Thin‐film transistors (TFTs) based on amorphous indium‐gallium‐zinc‐oxide (a‐IGZO) have attracted vast attention for use in organic light‐emitting diode (AMOLED) displays due to their high electron mobility and large current on–off ratio. Although amorphous oxide semiconductors show considerably less threshold voltage (Vth) variation than poly‐silicon, large‐area processing and degradation effects can impede the characteristic parameters of a‐IGZO TFTs, which manifests in an uneven brightness distribution across the display panel. Such Vth variations are usually reduced by additional compensation circuits consisting of TFTs and capacitors. Herein, a new approach to compensate such variabilities is demonstrated: the integration of a programmable ferroelectric (FE) film in the gate stack of the TFT. This simplifies the complexity of the pixel cell and potentially minimizes the need for compensation circuits, which is crucial for transparent displays. To test this new approach, fully integrated FE‐TFTs (i.e., with vias contacting a structured bottom gate electrode from the top) based on a‐IGZO and FE hafnium‐zirconium oxide (HZO) are developed. A single low‐temperature post‐fabrication treatment at 350 °C for 1 h in air is used to simultaneously crystallize the HZO film in the FE phase and to reduce the number of defects in the a‐IGZO channel. The structural and electrical characterizations provide comprehensive guidance for the design of effective FE‐TFT gate stacks and device geometries. An accurate control of the polarization state and linear switching between multiple intermediate states is shown by using programming pulses of various amplitudes and widths. Furthermore, a direct correlation between the channel length and the applied pulse width for programming is observed.

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Utilizing ionizing radiation for in situ studies in liquid media enables unique insights into nanostructure formation dynamics. As radiolysis interferes with observations, kinetic simulations are employed to understand and exploit beam‐liquid interactions. By introducing an intuitive tool to simulate arbitrary kinetic models for radiation chemistry, it is demonstrated that these models provide a holistic understanding of reaction mechanisms. This is shown for irradiated HAuCl4 solutions allowing for quantitative prediction and tailoring of redox processes in liquid‐phase transmission electron microscopy (LP‐TEM). Moreover, it is demonstrated that kinetic modeling of radiation chemistry is applicable to investigations utilizing X‐rays such as X‐ray diffraction (XRD). This emphasizes that beam‐sample interactions must be considered during XRD in liquid media and shows that reaction kinetics do not provide a threshold dose rate for gold nucleation relevant to LP‐TEM and XRD. Furthermore, it is unveiled that oxidative etching of gold nanoparticles depends on both, precursor concentration, and dose rate. This dependency is exploited to probe the electron beam‐induced shift in Gibbs free energy landscape by analyzing critical radii of gold nanoparticles.