A5057467750- Advanced Thermoelectric Materials and Devices
- Conducting polymers and applications
- Thermal Radiation and Cooling Technologies
- Thermal properties of materials
- Advanced Thermodynamics and Statistical Mechanics
- Organic Electronics and Photovoltaics
- Advanced Sensor and Energy Harvesting Materials
- Thermal Expansion and Ionic Conductivity
- Molecular Junctions and Nanostructures
- Solar Thermal and Photovoltaic Systems
- Optical properties and cooling technologies in crystalline materials
- Advanced Battery Materials and Technologies
- Perovskite Materials and Applications
- Quantum Electrodynamics and Casimir Effect
- Nuclear reactor physics and engineering
- Advanced ceramic materials synthesis
- Advanced battery technologies research
- Nuclear Materials and Properties
- Thermography and Photoacoustic Techniques
- Solar-Powered Water Purification Methods
- Supercapacitor Materials and Fabrication
- Transition Metal Oxide Nanomaterials
- Analytical Chemistry and Sensors
- International Law and Human Rights
- solar cell performance optimization
Georgia Institute of Technology
2015-2024
National Renewable Energy Laboratory
2021-2024
University of Wisconsin–Madison
2024
Atlanta Technical College
2023
Lawrence Berkeley National Laboratory
2013-2022
Arizona State University
2021
AID Atlanta
2014-2020
University of California, Berkeley
2010-2017
University of Michigan
2013
Research Experiences for Undergraduates
2013
Thermoelectric materials for power generation are typically compared using the dimensionless figure-of-merit ZT because it relates directly to device efficiency. However, practical applications, cost of – as governed by material, manufacturing, and heat exchanger costs is also a critical factor which not captured in alone. The necessary analysis, derived herein, optimizes coupled thermoelectric economic problem leg length, L, system fill factor, F, functions these costs. Fuel, operating,...
The electrical behavior of a conducting-polymer/inorganic-nanowire composite is explained with model in which carrier transport occurs predominantly through highly conductive volume polymer that exists at the polymer-nanowire interface. This result highlights importance controlling nanoscale interfaces for thermoelectric materials, and provides general route improving organic/inorganic composites. As service to our authors readers, this journal supporting information supplied by authors....
The thermoelectric properties of a unique hybrid polymer-inorganic nanoparticle system consisting tellurium nanowires and conducting polymer, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), can be optimized by both controlling the shape nanoparticles loading doping polymeric matrix with polar solvents. mechanism for an observed improvement in power factor is attributed to nature PEDOT:PSS, which exhibits transition from hopping transport-dominated regime carrier...
Abstract Molecular doping is a powerful method to fine‐tune the thermoelectric properties of organic semiconductors, in particular impart requisite electrical conductivity. The incorporation molecular dopants can, however, perturb microstructure semicrystalline which complicates development detailed understanding structure–property relationships. To better understand how pathway and resulting dopant counterion influence performance transport properties, new dimer dopant, (N‐DMBI) 2 ,...
Thermoelectricty in heterojunctions, where a single-molecule is trapped between metal electrodes, has been used to understand transport properties at organic-inorganic interfaces. (1) The these systems highly dependent on the energy level alignment molecular orbitals and Fermi (or work function) of contacts. To date, majority measurements have focused simple small molecules dominated through highest occupied orbital. (2, 3) In systems, limited by absence electrode materials with low levels...
Abstract This study reports on the thermoelectric properties of poly(3‐alkylchalcogenophene) thin films (500 nm) as a function heteroatom (sulfur, selenium, tellurium), and how these change with dopant (ferric chloride) concentration. UV–vis–NIR spectroscopy shows that polaronic charge carriers are formed upon doping. Poly(3‐alkyltellurophene) (P3RTe) is most easily doped followed by poly(3‐alkylselenophene) (P3RSe) poly(3‐alkylthiophene) (P3RT), where R = 3,7‐dimethyloctyl chain pendant...
Abstract Integrating thermoelectric generators (TEGs) into textiles is attractive for body heat harvesting to power wearable electronics. Textile‐integrated TEGs have the advantage of conformity that ensures efficient transfer and does not impede movement. Additive printing techniques solution processable polymer‐based (TE) materials can be used this purpose. However, a number fabrication challenges limit realization printed textile TEG using low cost, scalable, compatible process. In work,...
Abstract Polymer dielectrics find applications in modern electronic and electrical technologies due to their low density, durability, high dielectric breakdown strength, design flexibility. However, they are not reliable at temperatures mechanical integrity thermal stability. Herein, a self‐assembled nanocomposite is reported, which integrates 1D polyaramid nanofibers 2D boron nitride nanosheets through vacuum‐assisted layer‐by‐layer infiltration process. The resulting exhibits hierarchical...
The processability and electronic properties of conjugated polymers (CPs) have become increasingly important due to the potential these materials in redox solid-state devices for a broad range applications. To solubilize CPs, side chains are needed, but such reduce relative fraction electroactive material film, potentially obstructing π-π intermolecular interactions, localizing charge carriers, compromising desirable optoelectronic properties. deleterious effects chains, we demonstrate that...
The transport properties of a junction consisting small donor-acceptor molecules bound to Au electrodes are studied and understood in terms its hybrid donor-acceptor-electrode interfaces. A newly synthesized molecule bithiophene donor naphthalenediimide acceptor separated by conjugated phenylacetylene bridge nonconjugated end group shows rectification the reverse polarization, behavior opposite that observed mesoscopic p-n junctions. Solution-based spectroscopic measurements demonstrate...
ABSTRACT Electrically conducting polymers are attractive for thermoelectric generators (TEGs) because of their low thermal conductivity and solution processability. In this article, we report on the performance a radial device made from n‐ p‐type printed paper substrates. Our (TE) models predict an optimized geometry that operates under natural convective cooling alone, herein, fabrication new organic TEG. We used poly(nickel‐1,1,2,2‐ethenetetrathiolate) blended with poly(vinylidene...
Transient thermoreflectance (TTR) techniques are ubiquitous methods for measuring thermal conductivity of bulk materials and thin-films. Both through-plane k⊥ in-plane k∥ should be independently measured in transversely anisotropic materials. When these properties using conventional TTR techniques, the accuracy measurement is dependent on vice versa. This especially problematic thin-films measurements as uncertainty (∼5%) can propagate grow k∥. In this paper, we present a method simultaneous...
Thermoelectric generators (TEGs) are solid-state heat engines consisting of p-type and n-type semiconductors that convert into electricity via the Seebeck effect. Conducting polymers a viable alternative with intrinsic advantages over their inorganic counterparts, since they abundant, flexible as thick-films, have reduced manufacturing costs due to solution processing. Furthermore, an inherently low thermal conductivity, thus affording them option forgoing some exchanger costs. Current...
Abstract Conjugated polymers with high electrical conductivities are attractive for applications in capacitors, biosensors, organic thermoelectrics, and transparent electrodes. Here, a series of solution processable dioxythiophene copolymers based on 3,4‐propylenedioxythiophene (ProDOT) 3,4‐ethylenedioxythiophene (EDOT) is investigated as thermoelectric electrode materials. Through structural manipulation the polymer repeat unit, conductivity upon oxidative doping tuned from 1 × 10 −3 to 3 S...
Abstract Nickel ethenetetrathiolate (NiETT) polymers are promising n‐type thermoelectric (TE) materials, but their insolubility requires the use of an inert polymer matrix to form films, which is detrimental TE performance. In this work, thermal annealing as a post‐treatment process simultaneously enhances electrical conductivity from 6 ± 2 23 3 S cm −1 and thermopower −28 −74 4 µV K for NiETT/PVDF composite films. Spectroscopic characterization reveals that underlying mechanism involves...
A thermal diode is a two-terminal device that allows heat to transfer more easily in one direction (forward bias) than the opposite (reverse bias). photonic operates contactless mode and may afford large operating temperature range. Here, near-field based on hexagonal boron nitride (hBN) indium antimonide (InSb) films theoretically demonstrated. The dependence of interband absorption InSb used couple (or decouple) with hyperbolic phonon polaritons hBN. numerical analysis predicts...