Highlights

The objective of this effort is to design and develop well defined p-n heterostructures that allow the investigation of their optoelectronic properties due to interfacial interactions.

Promising a myriad of transformative applications in various fields such as communications, security, chemical & biological sensing, and astronomy, terahertz (THz) technology is a very promising technological field. In order to realize efficient THz systems, development of active devices, such as detectors and emitters is required.

The groups of Kagan, Murray, and Engheta in IRG3 teamed up to (a) synthesize gold (Au) nanorods (length of ~110 nm, diameter of ~22 nm) and direct their assembly in lithographically-defined templates to form nanorod equilateral trimers. Axial displacement of the nanorods created “right-handed” (R) and left-handed (not shown) two-dimensional chiral enantiomers.

As part of our commitment to outreach, two students working with David Chenoweth in this IRG  (Alexander Kasznal and Samuel Melton) are involved in Spark mentoring programs. Spark Students are paired with a mentor based on mutual interests. Students visit their mentor’s workplace once a week for 10-13 weeks. Students experience the value of planning, implementation and practice with the creation of a Spark Project.

A collaboration (Wells, Shenoy) in IRG 2 studied the mechanisms of mechanical plasticity in collagen networks resulting from contractile forces produced by cellular aggregates placed within them. The Wells group used fibroblast spheroids seeded atop collagen gels to study the plasticity of collagen fiber networks due to cell-induced forces. Second harmonic generation imaging and spectral analysis enabled quantification of the alignment of fibers between a pair of contractile cell clusters.

Starting in 2017, the LRSM and Singh Center for Nanotechnology hosted monthly field trips for Philadelphia middle and high school students. During these visits, students had introductory lessons on Materials Science and Nanotechnology and suited up for the clean room at the Quattrone Nanofabrication facility, where they observed and, when possible, assisted with lithography and soft-lithography. 124 students from four schools participated in the field trip program, of which 81% were URM and 96% were low-income (i.e., they qualify for the Federal Free and Reduced Lunch program).

Large-area growth of monolayer films of transition metal dichalcogenides is important in the rapidly advancing research field of topological materials, because scientists believe tungsten ditelluride has so-called “topological” electronic states. To this end, the Penn MRSEC SuperSeed team (Rappe, Johnson) and IRG faculty (Carpick, IRG-3; Kikkawa, IRG-4) collaborated to develop a growth process methodology for synthesis of reliable and reproducible large-area many-monolayer 1T'-WTe2 flakes.

Next-generation 'smart' nanoparticle systems should be precisely engineered in size, shape and composition to introduce multiple functionalities, unattainable from a single material. Bottom-up chemical methods are prized for the synthesis of crystalline nanoparticles, i.e., nanocrystals with size-and shape-dependent physical properties, but they are less successful in achieving multifunctionality. Top-down lithographic methods can produce multifunctional nanoparticles with precise size and shape control, yet this approach becomes increasingly difficult at sizes of order 10 nm.

Stable glasses produced by physical vapor deposition are important to understand. They exhibit optical birefringence, which traditionally implies that the constituent molecules are aligned.

Vesicle fusion and fission processes often occur in biological systems, usually with the aid of specialized proteins. Percec, Klein, Hammer, and Baumgart carried out comprehensive fusion/fission experiments based on three membrane ingredients: hydrogenated (RH), fluorinated (RF), and hybrid-hydrogenated/fluorinated (RHF) Janus dendrimers (Figure – Top Left).