A Simple and Robust Approach to Reducing Contact Resistance in Organic Transistors

12/1/2018 | Z. A. Lamport, K. J. Barth, H. Lee, E. Gann, S. Engmann, H. Chen, M. Guthold, I. McCulloch, J. E. Anthony, L. J. Richter, D. M. DeLongchamp, and O. D. Jurchescu

Contact effects limit device performance, even in the case of high-mobility semiconductors. We developed a strategy for drastically reducing contact effects: it consists in creating high work function domains at the surface of the injecting electrodes to promote channels of enhanced injection.

MOVCD of Complex Nitride Semiconductors

11/26/2018 | K. Kash, W. Lambrecht, H. Zhao

A unique, custom-designed research instrument for metal-organic chemical vapor deposition (MOCVD) is enabling the synthesis and study of complex nitride semiconductors, such as ZnGeN21, and alloys and heterostructures of these materials, alone and in combination with the binary nitrides (Al,Ga,In)

Tunable Semiconductors: Organic-inorganic Hybrids

10/4/2018 | W. You, Y. Kanai (U. NC); D. Mitzi, V. Blum (Duke U.)

We use high-level computational theory to demonstrate how a novel class of crystalline semiconductor materials, so-called layered hybrid organic-inorganic perovskites (HOIPs), can be designed at the atomic scale to provide targeted semiconductor properties. The tun-ability of the materials arises from the atomic-scale combination of an inorganic semi-conductor integrated with functionalized organic molecules that offer a wide range of properties.

Materials from Mathematics

8/30/2018 | Richard D. James, University of Minnesota

Austenite/martensite interface in Cu69.5Al27Ni3.5. Zero elastic energy austenite/martensite interfaces possible under the co-factor conditions. Red is austenite and blue/green are two variants of martensite. These pictures exhibit large deformations, zero elastic energy, and perfect fitting of the phases under continuous variation of the volume fraction f.

Controlling Emission in Optical Materials

8/21/2018 | Amar H. Flood (PI), Steven L. Tait, Krishnan Raghavachari, Peter J. Ortoleva

If we can understand how the packing gives rise to the optical properties, then we can control the packing to generate materials of any color and brightness.

Predicting the Rubbery Response of Polymer Liquids

7/31/2018

Our work describes how different kinds of polymer entangle. The key insight is simple to state intuitively: polymer chains entangle as often as they can, limited only by how often they can closely approach each other. We turn this deceptively simple statement into a unified scaling theory for different kinds of polymer fluids.

Discovery, Development and Deployment of High Temperature Coating – Substrate Systems

5/18/2018 | Tresa M. Pollock

This DMREF program engages a multidisciplinary team from Materials, Computer Science and Mechanical Engineering to develop a fundamental framework for design of a new class of multilayered systems that could impact new, energy efficient power generation and propulsion systems.

Data Mining for Parameters Affecting Polymorph Selection

4/1/2018 | Yueh-Lin (Lynn) Loo (Princeton U.)

The macroscopic properties of molecular materials can be drastically influenced by their solid-state packing arrangements, of which there can be many (e.g., polymorphism). Strategies to controllably and predictively access select polymorphs are desired, but predicting the conditions necessary to access a given polymorph is challenging with the current state of the art.

Degradable Block Copolymers

3/20/2018 | Karen Wooley (Texas A&M University)

Fully degradable amphiphilic block polymers derived from three natural products, l-lactide, l-cysteine and d-glucose were synthesized and assembled in solution into spherical and cylindrical nanostructures. The solution assembly process was driven by crystallization of the poly(l-lactide) (PLLA) block and involved heating the polymers in water at 65 °C for 30 hours, followed by cooling the solutions to room temperature.

Defect & Dopant Predictions for Thermoelectric Materials

3/20/2018 | https://dmref.org/files/13bc53a2-6be6-4e57-855e-ff7d538df0c1

Challenge: Defects and scarcity of dopants often are the Achilles heel to realizing the theoretical potential of new semiconductors (eg transparent conductors, thermoelectrics). Further, native defects and dopants are computationally expensive to accurately calculate. Two approaches to overcome this challenge are in progress:

Research Highlights