Research Topics

In the Ratcliff group, we are broadly interested in materials synthesis, structural control, processing, and transport phenomena of low cost semiconducting materials and interfaces.  Our particular emphasis is organic-based electronic devices. Polymeric and organic semiconductors offer mechanical flexibility and tailorable properties through synthesis, which makes them exceptionally promising in next-generation electronics.

Our overarching goals are developing exciting opportunities in flexible devices for bioelectronics and energy harvesting and storage, all with reduced manufacturing cost and lessened environmental impact. To achieve this goal, we must understand the molecular-level composition and structure controlling charge transfer and charge transport properties.  

 

Organic Bioelectronics and Sensors

Interfacing electronic materials with biological systems improves understanding of bimolecular interactions and promotes application of solid-state devices in biology and medicine.  One key area of interest is molecular sensing, focusing on detection of biomarkers in human sweat for local or remote monitoring of human operator function.  Conductive polymers are especially promising bioelectronic materials, with high flexibility to match tissue modulus, low toxicity, and electronic properties that are highly influenced by both electrical charges and ions.

 

Organic electrochemical transistors (OECTs) and electrolyte-gated organic transistors leverage the hybrid electrical-ionic conduction mechanism of organic semiconductor active elements. This unique conduction property yields higher transconductance and lower operating voltages relative to inorganic transistors, with enhanced sensitivity in high ionic strength environments.  We are interested in fundamental structure-property relationships and transport properties of these materials, interfaces and devices. 

 

(Photo)Electrochemical Cells for Energy Conversion and Storage

Polymer/liquid interfaces are critical for energy conversion in solar fuels and molecular catalysis, redox flow batteries, supercapacitors, fuel cell, thermogalvanic, electrochromic, and novel dye cell applications.

Polymers are highly advantageous, as the electronic properties can be tuned to match redox potentials of small molecule targets such as CO2 or H2O or other redox-active molecules, while also controlling optical properties for photon absorption.  If we can understand transport phenomena and charge transfer of polymer/electrolyte interfaces, we can drive the search for new materials with improved functionality.  In the Ratcliff group, we are developing interfacial design strategies to control matter on the atomic scale and how to characterize the functionality of these interfaces at relevant length scales (nano to micron).