Congratulations to Professors Jim Cahoon (UNC), David Mitzi (Duke) and Aram Amassian (NC State) for receiving NSF funding to launch a new collaborative REU site focused on hybrid perovskite materials. Under this award, twelve students will conduct research in faculty labs across the three RTNN institutions. To strengthen inter-institutional relationships, each student will partner with a peer working on a complementary project at a different RTNN university. Team-building, professional development, and social activities will be interwoven into the program schedule. The first cohort of students will begin in summer 2022.
There are three objectives for this REU program: (1) To provide a hands-on research experience in hybrid perovskite materials that reinforces student knowledge of cutting-edge characterization techniques and analytical tools that can be used to evaluate the nanoscopic structure of hybrid perovskite systems; (2) to foster student interest in pursuing a career in STEM fields, especially those from underrepresented groups; and (3) to develop communication and networking skills in each of the participants.
More information for the program will be posted on the RTNN website in Fall 2021. If you are interested in receiving updates about this exciting new program, please contact Maude Cuchiara (email@example.com).
The RTNN hosted 11 educators this summer from Durham, Johnston, Wake, and Chatham Counties. The educators worked in small teams in research labs at NC State, Duke, and UNC as well as a start-up company, Smart Material Solutions. During their time in the program, educators were exposed to and participated in research in cutting-edge laboratories. They also had the opportunity to utilize multiple nanotechnology techniques and tools in RTNN facilities including atomic layer deposition, photolithography, scanning electron microscopy, and atomic force microscopy. Projects ranged from the creation and analysis of thin films to the development of new filter materials. Educators also wrote innovative lesson plans linked to their research to bring back to their home institutions. The program culminated in a poster session where teachers shared their summer work and how they will use their experiences in their classroom.
NC State researchers are now using a microfluidic system to create quantum dots across the visible light spectrum. The use of microfluidics significantly reduces manufacturing costs and enables real-time process monitoring. Quantum dots can be used in a variety of applications including LED displays and solar energy. For more information, visit the NC State News Release or the original paper in Advanced Functional Materials (details below).
Authors: Kameel Abdel-Latif, Robert W. Epps, Corwin B. Kerr, Christopher M. Papa, Felix N. Castellano and Milad Abolhasani, North Carolina State University
Published: March 15, Advanced Functional Materials
Abstract: In an effort to produce the materials of next-generation photoelectronic devices, post-synthesis halide exchange reactions of perovskite quantum dots have been explored to achieve enhanced band-gap tunability. However, comprehensive understanding of the multifaceted halide exchange reactions has been inhibited by their vast relevant parameter space and complex reaction network. In this work, we present a facile room temperature strategy for rapid halide exchange of inorganic perovskite quantum dots. We provide a comprehensive understanding of the halide exchange reactions by isolating reaction kinetics from precursor mixing rates utilizing a modular microfluidic platform, QDExer (Quantum Dot Exchanger). We illustrate the effects of ligand composition and halide salt source on the rate and extent of the halide exchange reactions. Our fluidic platform offers a unique time- and material-efficient approach for studies of solution phase-processed colloidal nanocrystals beyond those studied here and may accelerate the discovery and optimization of next-generation materials for energy technologies.
“Imaging and Quantitative Analysis of Insecticide in Mosquito Net Fibers Using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS)”
Stephen C. Smith, Centers for Disease Control and Prevention; Chuanzhen Zhou, Fred A. Stevie, and Roberto Garcia, North Carolina State University
Abstract: Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis was used to qualitatively and quantitatively assess the distribution of permethrin insecticide on the surfaces and interiors of Olyset® long-lasting insecticidal net (LLIN) fibers. Total insecticide content in LLINs has been established using many analytical methods. However, it is important to quantify the bioavailable portion residing on the fiber surfaces for incorporated LLINs. ToF-SIMS is a very surface sensitive technique and can directly image the spatial distribution of permethrin insecticide on the surface of Olyset fibers. Surface permethrin appeared as patchy deposits which were easily removed by acetone and reappeared after several days as interior permethrin migrated (bloomed) from the fiber interior. After a wash/incubation cycle, permethrin deposits were more diffuse and less concentrated than those on the as-received fibers. ToF-SIMS is particularly sensitive to detect the Cl- ion, which is the characteristic ion of permethrin. Ion implantation and quantification of dopants using SIMS is well established in the semiconductor industry. In this study, quantitative depth profiling was carried out using 35Cl– ion implantation to correlate secondary ion yield with permethrin concentration, yielding a limit of detection of 0.051 wt% for permethrin. In some cases, surface concentration differed greatly from the fiber interior (>1 µm below the surface). Two- and three-dimensional mapping of Cl at sub-micrometer resolution showed permethrin to be dissolved throughout the fiber, with about 2 vol% residing in disperse, high-concentration domains. This suggests that these fibers fall into the class of monolithic sustained-release devices. It is expected that ToF-SIMS can be a valuable tool to provide insight into the insecticide release behavior of other LLIN products, both current and future.