Wei Liu, Oxford Instruments

Raman spectroscopy has been widely used in the recent development of semiconductor, energy storage and quantum materials, high speed and high resolution confocal Raman imaging provides extremely valuable material information. Newly launched witec 360 with Hexalight spectrometer brings a few spectroscopic technologies into one integrated solution, including but not limited to Raman, PL and SHG imaging capabilities, which enables a comprehensive, non‑destructive characterization workflow for material studies. In this presentation, system configuration will be introduced and a number of application will be discussed to show case these capabilities.

Kate Kiseeva

TBD

Cheryl Yao

Airborne microplastics (MPs) are emerging contaminants of concern because of their potential impacts on human health and their contribution to pollution in water, soil, and sediment. This study investigated the distribution, composition, and morphology of airborne microplastics in indoor and ambient air in northern New Jersey, USA. Microplastic fibers, films, and fragments composed of polystyrene (PS), polyethylene terephthalate (PET), polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) were identified in offices, hallways, classrooms, and a single-family house. The deposition rates of synthetic fibers, ranging from 35 µm to 1000 µm in length, were highest in the single-family house and lowest in the classroom, suggesting that residential environments may be important sources of airborne microplastic fibers. In contrast, film-like microplastics with surface areas of 200-5000 µm2 showed the highest deposition rate in the classroom and the lowest in the hallway, likely reflecting intensive use of plastic film materials in classroom settings. The deposition rate of microplastics in ambient air collected on a building roof was only about 2-8% of indoor deposition rates. Microplastics with similar textures but different sizes were identified in both total atmospheric deposition and particulate samples (PM2.5 and PM10), suggesting ongoing fragmentation from microplastics to smaller particles, potentially including nanoplastics. PE particles and fibers dominated indoor air samples, whereas PVC fragments were more prevalent in outdoor ambient air. Overall, these findings provide new insight into the characteristics of airborne microplastics in urban environments and improve our understanding of their sources, transport, fate, and potential health risks.

Wei Liu, Oxford Instruments

Raman spectroscopy is a traditional technology for chemical identification of materials. Combined with confocal microscopy, confocal Raman imaging has been used widely in the advanced material analysis, it is even more powerful when other imaging techniques such as AFM/photoluminescence/SHG are built in one system like witec360. Recent material development asked for more: running confocal Raman in non-conventional ways: extreme temperature from CVD reactor of 870 C to liquid helium cryostage, glove box for controlled chemical environment, large sized loading frame etc.. Fiber based witec 360 system provides great solutions for these requests through its unique modularity and flexibility, application examples will be discussed in this presentation.

Ted Limpoco

We have developed the first commercial atomic force microscope to use quadrature phase differential interferometry (QPDI) which greatly improves the accuracy and precision of AFM measurements. This is not the first AFM to use interferometric sensing. Several early implementations were abandoned because of their complexity, limited measurement range, and poor low-frequency noise performance. When optical beam deflection (OBD) was introduced in 1988, it became the standard AFM detection system until today.​

St. John Whittaker

An estimated 1/3 of molecular crystals can be prompted to grow as banded spherulites, which are polycrystalline aggregates of helical fibers. Between glass slides, banded spherulites form as thin films which expose different crystallographic facets at the film-air interface along the fiber helical axis. The crystalline anisotropic properties are therefore patterned, which include refractive index, absorbance, fluorescence, conductivity, and solubility, to name a few. Three separate projects are discussed which revolve around the usage of an Asylum atomic force microscope (AFM) to probe the chiral structures present in banded spherulite films. Because the twisting pitch of the helical crystals is variable and controllable, AFM is well-suited to probe these systems. AFM can map the spatial distribution of properties, ultimately allowing for correlation between crystalline orientation and a corresponding anisotropic property. Three unique applications will be discussed which range from nanoscopic interfacial facet measurements, conductivity measurement in thin films, and a custom photoconductivity module.

Ted Limpoco

2D materials are currently a hot topic in the materials research community as they have been shown to exhibit novel mechanical, optical and electrical properties. Graphene, specifically twisted graphene, exhibits Moiré superlattices that are of particular interest. These samples are prepared by imaging the graphene flakes, cutting them, rotating, and transferring them to new substrates in a specific order. Precise control over the manipulation of graphene and in-depth characterization of the resulting sample properties are crucial steps in the preparation of new and performant 2D material-based devices. To achieve this, a high-performance Atomic Force Microscope (AFM) is the instrument of choice. We present here the best imaging modes and setups to facilitate the twisted graphene sample preparation and characterization. Topography, conductivity, friction and piezoelectric data will be shown and discussed in the context of sample preparation and the expected sample properties.