The combination of molecularly imprinted polymer (MIP) technology with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is presented with focus on optimization of the LA-ICP-MS parameters such as laser beam diameter, laser beam fluence, and scan speed using CdS quantum dots (QDs) as a template and dopamine as a functional monomer. Correlative Probe and Electron Microscopy (CPEM) was used for the surface analysis allowing simultaneous acquisition of SEM and AFM images at the same place, in the same coordinate system. This combination of AFM/SEM measuring reveals surface inequalities and enables obtaining of true correlative data enabling their easier interpretation with high resolution in all 3 dimensions.
The need to characterize and analyze structures in the (sub)nanometer range is growing. The complexity of measuring methods and advanced instruments in this field also creates a demand for innovatory ways of correlative analysis, easy-to-use instrumentation, and automated procedures. To tackle these market demands, NenoVision has developed a unique AFM LiteScope, designed for easy integration into the SEM. The motivation behind this hybrid system design is twofold – first, it allows for efficient, yet complex in-situ sample characterization. Second, it brings completely new possibilities for advanced correlative imaging and analyzing samples in a way that was difficult or impossible by separate SEM and AFM systems.
Microscopy & Microanalysis
One of the key steps in the progress in scientific instrumentation and analytical methods is the development of assembling of various techniques into the compact apparatus. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) are both well established and commonly used techniques for nanoworld imaging. These technologies were already integrated in the past but their imaging techniques were used separately. Correlative Probe and Electron Microscopy (CPEM) is based on a different principle than the traditional approach and it enables simultaneous acquistition of various signals including the AFM surface topography and mechanical properties, and SEM signals, such as SE and BSE.
Theoretical and Applied Fracture Mechanics
The fatigue hardening, softening, and crack initiation on the MAR-M247 superalloy were observed and measured at different temperatures. The plastic strain localization resulted in the formation of persistent strip markings on the surface of specimens. The surface relief after low cycle fatigue tests at 23 °C, 700 °C, and 800 °C was observed using our AFM LiteScope in tapping mode. The Correlative Probe and Electron Microscopy (CPEM) enabled the reconstruction of the surface in 3D, combining the best of HRSEM and AFM techniques.
In this research, LiteScope was used for the characterization of graphene and I/V spectroscopic measuring. The successful grafting of alkynyl groups onto graphene via the Sonogashira reaction between fluorographene and terminal alkynes was reported. Theoretical calculations revealed that fluorographene can efficiently bind and oxidize the palladium catalyst on electrophilic sites activated by fluorine atoms. This paves the way towards conductive and mechanically robust 3D covalent networks.
Journal of Materials Science
How to effectively improve the efficiency of light absorption and exciton separation? That is a major challenge for polymer solar cells. In this study, AuNPs with the particle size of about 30 nm were prepared by Frens reduction method. Subsequently, the dopamine (DA) self-polymerized on their surface, creating a core-shell structural material Au@PDA. By regulating the DA polymerization time, PDA shells with different thickness were obtained. AFM-in-SEM microscope LiteScope was used to measure the morphology of ITO/Au@PDA(1 h)/ZnO and ITO/ZnO composite films.
International Journal of Nanotechnology in Medicine & Engineering
The article focuses on the advantages of using Akiyama probes in the AFM-in-SEM LiteScope in biology. Because of its unique structure, the Akiyama probe can be also regarded as a tuning fork probe. Its advantages are especially significant under the conditions in which traditional SEM technology could not provide us with enough data about the sample and an extension of the traditional imaging procedures is needed. Akiyama probes´ measuring modes were explored and compared with alternative probes.
The delamination of bismuth ferrite prepared by atomic layer deposition (ALD) on highly oriented pyrolytic graphite (HOPG) substrate was studied. The topography of Bi-Fe-O thin films was studied under atmospheric conditions and in a vacuum using the Correlative Probe and Electron Microscopy (CPEM). Besides advanced correlative imaging, installing AFM into the SEM enabled protection from acoustic vibrations, thermal drift, and other noise exposure. The complementary AFM and SEM analysis provided the possibility of testing the mechanical properties by using pressure.
Applied Surface Science
Fluorographene is a fully fluorinated derivative of graphene. Unlike graphene, fluorographene is a wide gap semiconductor/insulator that holds great potential for applications requiring two-dimensional dielectric nanomaterials. Despite growing interest and a well-defined structure, the basic questions of fluorographene’s band gap nature and value remain a conundrum. Here, we resolve this long-standing issue, demonstrating a direct optical band gap at 5.75 eV by means of diffuse reflectance spectroscopy. The nature of the band gap and the factors contributing to earlier controversies are explained by combining spectroscopic methods, ab initio calculations based on the finite momentum Bethe-Salpeter equation, and structural characterization via x-ray diffraction and Raman scattering. Ab initio calculations complement the experimental results by showing an excitonic peak at 5.65 eV of a Frenkel exciton bound to a single atom. The calculations also reveal that the absorption bands at lower energies arise from the presence of fluorine vacancies in the material, which explains earlier controversies in the literature about the band gap of fluorographene.
Materials & Design
This study is focused on the preparation of new hybrid layers intended for surface modification of Ti-6Al-4V alloys for potential orthopaedic and dental applications. LiteScope was used there to perform surface analysis of material coatings, for examination of their topography and roughness. The hybrid oxide layers newly developed in this study – especially the layers with Zr – resulted as a promising material for coating metallic bone implants.
The paper presents the characterization of the microstructure evolution during flow forming of austenitic stainless steel AISI 304L. Due to plastic deformation of metastable austenitic steel, phase transformation from γ-austenite into α’-martensite occurs. This is initiated by the formation of shear bands as product of the external stresses. By means of coupled microscopic and micromagnetic investigations, a characterization of the microstructure was carried out. The research contributes to the development of micromagnetic sensors to monitor the evolution of properties during flow forming. This makes them more suitable for closed-loop property control, which offers possibilities for an application-oriented and more efficient production.