Functional organic semiconductor and hybrid devices
Technologies society uses each day like photodetectors, solar cells, lasers, and sensors are dependent upon the morphology and interfaces of the constituent materials when deposited as a film. In other words, cell phones, breathalyzers, renewable energy, and countless other technologies are all dependent upon the fabrication and resulting interactions of some of their smallest parts. Dr. Adrienne Stiff-Roberts, Associate Professor of Electrical and Computer Engineering at Duke University, is developing a new thin-film deposition technique that has shown great promise in providing unprecedented control over organic-based materials. Her research is designed to understand the fundamental mechanisms and advantages of this technique, called emulsion-based, resonant infrared, matrix-assisted pulsed laser evaporation, or more simply, RIR-MAPLE. With RIR-MAPLE, she and her team will be able to remove the traditional limitations of solution-based processing, and furthermore, open up entirely new avenues for organic semiconductor devices and polymer-based films and surfaces, more generally.
By pioneering a novel approach to organic thin film deposition that combines solution and vacuum-processing, she and her team can provide many useful capabilities that are difficult, if not impossible, to achieve otherwise. Therefore, RIR-MAPLE offers a completely new way to integrate novel functions into films and devices with organic materials. As an example, organic solar cells have reached 12% efficiency, but are not yet practical for commercial application because the performance across a large solar panel is not consistent. Dr. Stiff-Robert’s thin-film deposition technique could help address this problem. In addition, RIR-MAPLE can create very uniform blends of polymers and inorganic nanoparticles, which could lead to new plasmonic applications, better materials for solar cells, and organic light emitting diodes using colloidal quantum dots. Thus, her technologies would help provide stronger platforms for renewable energy, biomedical sensors, anti-microbial applications, and more!
Current research includes:
Multi-functional Surfaces: Dr. Stiff-Roberts’ approach helps to combine different organic materials with designed functionality, without being limited by solubility. Therefore, she and her team can enable multi-functional surfaces with unique bulk properties enabled by the combination of disparate nanomaterials.
Nanocomposites: Dr. Stiff-Roberts’ ability to blend materials on the nanoscale has allowed her to create nanocomposites in which a polymer film is embedded with a uniform distribution of inorganic nanoparticles. Because her technology separates solvents from the deposited film, she and her team have more control over nanocomposite properties and more versatility in materials options. This is likely to have a large impact on renewable energy technologies in the future.
Applications: In the future, Dr. Stiff-Roberts hopes to demonstrate improved solar energy conversion using the advantages of RIR-MAPLE deposition. Possible approaches for improving solar cell efficiencies include depositing tandem solar cells to absorb more sunlight, depositing perovskite materials with optimized properties for solar energy conversion, and depositing nanocomposites comprising nanomaterials with diverse functionality to improve device efficiency. The nanoscale control of blended organic films also has great potential for application to antimicrobial surfaces and sensors for non-invasive glucose monitoring of diabetes.
Dr. Adrienne Stiff-Roberts was driven to academia by a passion to one day teach. Additionally, her father, a professor of mathematics education, served as a role model for the possibility of making a profession out of academia. He also piqued her interest in science during Saturday afternoons watching Doctor Who and Star Trek together. Yet, it wasn’t until her Junior year of high school when she was taking an AP Physics class that Dr. Stiff-Roberts knew she wanted to pursue a career in physics and engineering. In particular, she remembers participating in an elective course where she and other students were able to “play around with lasers.” Dr. Stiff-Roberts learned quickly and was inspired by applied problems where, if solved, she could have an impact on others.
Dr. Stiff-Roberts’ achievements in high school led to a scholarship, sponsored by NASA, to attend Spelman College, a small historically black college for women in Atlanta, Georgia. For Dr. Stiff-Roberts, Spelman College was a “place of empowerment.” There, she was able to focus on learning and to build the confidence to have an impact on academia and society at-large, despite the challenges of being a minority woman in the sciences. Dr. Stiff-Roberts participated in the Dual Degree Engineering Program, earning degrees in Physics from Spelman and Electrical Engineering from Georgia Tech, where she continued to be exposed to new learning environments and opportunities.
After completing her undergraduate degrees, Dr. Stiff-Roberts began her Ph.D. in Applied Physics. Eager to conduct research that made an impact in a responsible way, she was thrilled to find that University of Michigan provided limitless research opportunities in various fields. Despite previous struggles with her first introduction to quantum mechanics as an undergraduate, her favorite course during the first semester of graduate school was quantum mechanics, and the complex ideas finally started to make sense. After attending a lecture that connected quantum mechanics to lasers in semiconductor materials, she never looked back. This ah-ha moment motivated her towards the nexus of materials science, physics, and electrical engineering, where she has remained to this day.
Aside from research, Dr. Stiff-Roberts spends her free time with her husband and two young sons. She balances her busy work schedule with family and remaining active. She especially enjoys participating in martial arts with her sons, and she remains a science fiction fan.