The Reichmanis Group works at the interface of chemical engineering, chemistry, materials science, optics, and electronics spanning the range from fundamental concept to technology development and implementation. Research interests include the chemistry, properties and applications of materials technologies for optoelectronic and storage applications, with particular focus on polymeric and nanostructured materials for advanced technologies. Examples of current projects include
- Design, synthesis, and development of organic and hybrid semiconductor materials and processes for flexible, stretchable optoelectronic applications
- Exploration of structure-process-property relationships in organic and hybrid pi-conjugated materials to enable development of a “tool-box” for the design of materials with enhanced performance attributes
- Elucidation of conjugated polymer thin film nanostructure/microstructure evolution and its correlation with macroscopic charge transport;
- Design and development of materials systems for alternative energy applications, from energy conversion to energy storage;
- Harness nature’s ability to template the growth of ordered structures on the nanoscopic through macroscopic scales to develop “green” electronics.
Organic semiconductor design, synthesis and characterization: Although significant progress has been made, organic semiconducting polymers typically have low charge carrier mobility, low oxidation stability and a relatively large bandgap relative to their inorganic counterparts. From a molecular perspective, intra- and inter-molecular π-orbital overlap (or π – π stacking) determines charge transport performance. We are engaged in studying the effects of molecular co-planarity, intra-molecular charge transport and electron-withdrawing substitution on the optical and electronic properties of candidate polymers with the aim of facilitating their field-effect charge transport and photovoltaic performance. The use of appropriately substituted conjugated systems are also of interest for a range of sensor applications.
Fundamental structure-property-process relations in conjugated polymer semiconductors: To take full advantage of organic semiconductor technology, solution processed materials are required for conventional mass printing applications. The development of viable active polymer materials for such applications requires not only the development of relevant chemistries, but also the development of compatible device fabrication processes. We are developing efficient processing techniques to manipulate and control the micro-/macro-structure of the thin films and investigating how the resultant structure impacts macroscopic charge transport within the material. Techniques such as absorption and vibrational spectroscopy, atomic force microscopy, x-ray diffraction and electrical measurements of thin films are employed to understand relationships between molecular structure, thin film architecture, optical properties and macroscopic charge transport in organic/polymer/hybrid semiconductor materials. Features extracted from microstructural data are analyzed through image analysis, peak fitting, and other techniques from the rapidly growing field of data science. Efforts to elucidate the role of interfaces are also in progress.
Hybrid materials for advanced energy storage: Reliable rechargeable batteries with high energy density are critically needed for application including consumer electronics, energy storage grids and electric vehicles, among others. Serving as one example, flexible batteries are considered as a promising approach for the creation of practical, aesthetic electronic devices owing to their potential to
adapt to mechanical stress and thereby shape transformation. In that regard, considerable efforts have been aimed at developing robust flexible lithium-ion batteries based on incorporating advanced materials and constructing new flexible, systematic platforms, including adoption of soft materials such as polymer electrolytes, nano-sized active materials, and highly patterned, flexible current collectors. To accelerate the development of robust flexible batteries, we are investigating the interfacial chemical properties at three key interfaces of high-capacity composite battery electrodes. Through elucidation of the complex molecular to mesoscale interactions between electrode components, we can begin to develop the requisite fundamental chemical – structural relationships required for robust, next generation battery platforms.
Biomaterials: Biomaterials such as PSLG and cellulose nanocrystals are being explored for use in “green” electronics. Cellulose nanocrystals are rigid, rod-like structures that are dispersible in water. If these particles can enforce long-range order in semiconducting polymers, we expect that the charge carrier mobility will increase due to improved pi-pi stacking. Other cellulose derivatives such as cellulose nanofibrils show promise in paper-based battery applications as well.