rexresearch1
Paul THIBADO, et al.
Graphene Energy Harvester
Graphene Energy Harvester
https://news.uark.edu/articles/54830/physicists-build-circuit-that-generates-clean-limitless-power-from-graphene
Physicists Build Circuit That Generates Clean, Limitless Power From Graphene
Paul Thibado, professor of physics, with sample energy-harvesting chips under development.
A team of University of Arkansas physicists has successfully developed a circuit capable of capturing graphene's thermal motion and converting it into an electrical current.
“An energy-harvesting circuit based on graphene could be incorporated into a chip to provide clean, limitless, low-voltage power for small devices or sensors,” said Paul Thibado, professor of physics and lead researcher in the discovery.
The findings, titled "Fluctuation-induced current from freestanding graphene," and published in the journal Physical Review E, are proof of a theory the physicists developed at the U of A three years ago that freestanding graphene — a single layer of carbon atoms — ripples and buckles in a way that holds promise for energy harvesting.
The idea of harvesting energy from graphene is controversial because it refutes physicist Richard Feynman’s well-known assertion that the thermal motion of atoms, known as Brownian motion, cannot do work. Thibado’s team found that at room temperature the thermal motion of graphene does in fact induce an alternating current (AC) in a circuit, an achievement thought to be impossible.
In the 1950s, physicist Léon Brillouin published a landmark paper refuting the idea that adding a single diode, a one-way electrical gate, to a circuit is the solution to harvesting energy from Brownian motion. Knowing this, Thibado’s group built their circuit with two diodes for converting AC into a direct current (DC). With the diodes in opposition allowing the current to flow both ways, they provide separate paths through the circuit, producing a pulsing DC current that performs work on a load resistor.
Additionally, they discovered that their design increased the amount of power delivered. “We also found that the on-off, switch-like behavior of the diodes actually amplifies the power delivered, rather than reducing it, as previously thought,” said Thibado. “The rate of change in resistance provided by the diodes adds an extra factor to the power.”
The team used a relatively new field of physics to prove the diodes increased the circuit’s power. “In proving this power enhancement, we drew from the emergent field of stochastic thermodynamics and extended the nearly century-old, celebrated theory of Nyquist,” said coauthor Pradeep Kumar, associate professor of physics and coauthor.
According to Kumar, the graphene and circuit share a symbiotic relationship. Though the thermal environment is performing work on the load resistor, the graphene and circuit are at the same temperature and heat does not flow between the two.
That’s an important distinction, said Thibado, because a temperature difference between the graphene and circuit, in a circuit producing power, would contradict the second law of thermodynamics. “This means that the second law of thermodynamics is not violated, nor is there any need to argue that ‘Maxwell’s Demon’ is separating hot and cold electrons,” Thibado said.
The team also discovered that the relatively slow motion of graphene induces current in the circuit at low frequencies, which is important from a technological perspective because electronics function more efficiently at lower frequencies.
“People may think that current flowing in a resistor causes it to heat up, but the Brownian current does not. In fact, if no current was flowing, the resistor would cool down,” Thibado explained. “What we did was reroute the current in the circuit and transform it into something useful.”
The team’s next objective is to determine if the DC current can be stored in a capacitor for later use, a goal that requires miniaturizing the circuit and patterning it on a silicon wafer, or chip. If millions of these tiny circuits could be built on a 1-millimeter by 1-millimeter chip, they could serve as a low-power battery replacement.
The University of Arkansas holds several patents pending in the U.S. and international markets on the technology and has licensed it for commercial applications through the university’s Technology Ventures division. Researchers Surendra Singh, University Professor of physics; Hugh Churchill, associate professor of physics; and Jeff Dix, assistant professor of engineering, contributed to the work, which was funded by the Chancellor’s Commercialization Fund supported by the Walton Family Charitable Support Foundation.
https://thibado.uark.edu/
Thibado' Group / Univ. Arkansas
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https://www.thegraphenecouncil.org/blogpost/1501180/Graphene-News-and-Updates?tag=Paul+Thibado
$900,000 Awarded to Optimize Graphene Energy Harvesting Devices // by Terrance Barkan,
Tuesday, January 16, 2024
U of A physics professor Paul Thibado received a commitment of $904,000 from the WoodNext Foundation, administered by the Greater Houston Community Foundation. The five-year grant will support Thibado’s development of graphene energy harvesters.
“We have successfully developed a process for building graphene energy harvesting device structures,” Thibado said, “but current structures do not harvest enough power. This proposal will allow us to optimize these structures to harvest nanowatts of power, which is enough energy to run sensors.”
Thibado and his colleagues will develop graphene energy harvesting (or GEH) technology for the following sources of power: solar, thermal, acoustic, kinetic, nonlinear and ambient radiation. As each device is developed, his team will then build a full prototype sensor system around that specific power source.
Nancy Chan, executive director of the WoodNext Foundation, said, “We’re excited to support Paul’s work. We think it’s an important step in the development of more clean energy options, as well as a potentially exciting advance in building the internet of things.”
Thibado noted that current state-of-the-art sensor technology is powered by batteries that require microwatts (a millionth of a watt) of continuous power. The goal of his project is twofold:
1. Reduce sensor power demand to nanowatts (a billionth of a watt) and
2. Power these sensors using energy harvested from the local environment.
Notably, these systems will not include batteries, which have a limited lifespan, allowing them to achieve exceptionally long operational lifetimes — potentially several decades.
“Mass use of this technology will further expand the internet of things,” Thibado explained, “which transforms ordinary sensors into smart nodes within an intelligent network. Thus, our systems will impact a wide range of applications.”
How wide? Thibado envisions these sensors being used in transportation product tracking, logistic fleet management, livestock tracking, soil sensors, agricultural climate monitoring, environmental flood alerts, disaster planning, atmospheric monitoring, predictive maintenance, manufacturing process monitoring, utility smart meters/grids, city smart parking, traffic control, city lighting, waste management, bike/scooter management, camera systems, building alarm systems, temperature control, lighting, access, wearable fitness monitoring, child tracking and medical tracking. So, pretty wide.
The installation cost of GEHs is expected to be competitive with other forms of energy supply, both large and small scale. However, GEH’s operational cost will be near zero with no costs for fuel, charging, replacement or overhaul. For example, a GEH chip could be placed in a remote temperature sensor. This chip, a component of its electronic module, will free the device from the need for external power or batteries. The chip will not require replacement, as it has the same life as other components of the device. With GEH technology, the device can be more compact, portable and safeguarded from power failure.
Scientists Design Novel Nonlinear Circuit to Harvest Clean Power Using Graphene
Posted By Terrance Barkan, Friday, August 18, 2023
Obtaining useful work from random fluctuations in a system at thermal equilibrium has long been considered impossible. In fact, in the 1960s eminent American physicist Richard Feynman effectively shut down further inquiry after he argued in a series of lectures that Brownian motion, or the thermal motion of atoms, cannot perform useful work.
Now, a new study published in Physical Review E titled “Charging capacitors from thermal fluctuations using diodes” has proven that Feynman missed something important.
Three of the paper’s five authors are from the University of Arkansas Department of Physics. According to first author Paul Thibado, their study rigorously proves that thermal fluctuations of freestanding graphene, when connected to a circuit with diodes having nonlinear resistance and storage capacitors, does produce useful work by charging the storage capacitors. (Refer to the animation of circuit.)
The authors found that when the storage capacitors have an initial charge of zero, the circuit draws power from the thermal environment to charge them. The team then showed that the system satisfies both the first and second laws of thermodynamics throughout the charging process. They also found that larger storage capacitors yield more stored charge and that a smaller graphene capacitance provides both a higher initial rate of charging and a longer time to discharge. These characteristics are important because they allow time to disconnect the storage capacitors from the energy harvesting circuit before the net charge is lost.
This latest publication builds on two of the group’s previous studies. The first was published in a 2016 Physical Review Letters article entitled “Anomalous Dynamical Behavior of Freestanding Graphene Membranes.” In that study, Thibado and his co-authors identified the unique vibrational properties of graphene and its potential for energy harvesting. The second was published in a 2020 Physical Review E article entitled "Fluctuation-induced current from freestanding graphene," in which they discuss a circuit using graphene that can supply clean, limitless power for small devices or sensors.
This latest study progresses even further by establishing mathematically the design of a circuit capable of gathering energy from the heat of the earth and storing it in capacitors for later use.
“Theoretically, this was what we set out to prove,” Thibado explained. “There are well-known sources of energy, such as kinetic, solar, ambient radiation, acoustic, and thermal gradients. Now there is also nonlinear thermal power. Usually, people imagine that thermal power requires a temperature gradient. That is, of course, an important source of practical power, but what we found is a new source of power that has never existed before. And this new power does not require two different temperatures because it exists at a single temperature.”
In addition to Thibado, co-authors include Pradeep Kumar, John Neu, Surendra Singh, and Luis Bonilla. Kumar and Singh are also physics professors with the University of Arkansas, Neu with the University of California, Berkeley, and Bonilla with Universidad Carlos III de Madrid.
A DECADE OF INQUIRY
The study represents the solution to a problem Thibado has been studying for well over a decade, when he and Kumar first tracked the dynamic movement of ripples in freestanding graphene at the atomic level. Discovered in 2004, graphene is a one-atom-thick sheet of graphite. The duo observed that freestanding graphene has a rippled structure, with each ripple flipping up and down in response to the ambient temperature.
“The thinner something is, the more flexible it is,” Thibado said. “And at only one atom thick, there is nothing more flexible. It’s like a trampoline, constantly moving up and down. If you want to stop it from moving, you have to cool it down to 20 Kelvin.”
His current efforts in the development of this technology are focused on building a device he calls a Graphene Energy Harvester (or GEH). GEH uses a negatively charged sheet of graphene suspended between two metal electrodes. When the graphene flips up, it induces a positive charge in the top electrode. When it flips down, it positively charges the bottom electrode, creating an alternating current. With diodes wired in opposition, allowing the current to flow both ways, separate paths are provided through the circuit, producing a pulsing DC current that performs work on a load resistor.
COMMERCIAL APPLICATIONS
NTS Innovations, a company specializing in nanotechnology, owns the exclusive license to develop GEH into commercial products. Because GEH circuits are so small, mere nanometers in size, they are ideal for mass duplication on silicon chips. When multiple GEH circuits are embedded on a chip in arrays, more power can be produced. They can also operate in many environments, making them particularly attractive for wireless sensors in locations where changing batteries is inconvenient or expensive, such as an underground pipe system or interior aircraft cable ducts.
Donald Meyer, founder and CEO of NTS Innovations, said of Thibado’s latest effort: “Paul’s research reinforces our conviction that we are on the right path with Graphene Energy Harvesting. We appreciate our partnership with the University of Arkansas in bringing this technology to market.”
Ryan McCoy, NTS Innovations’ vice president of sales and marketing, added, “There is broad demand across the electronics industry to shrink form factors and decrease dependency on batteries and wired power. We believe Graphene Energy Harvesting will have a profound impact on both.”
Of the long road to making his latest theoretical breakthrough, Thibado said, “There was always this question out there: ‘If our graphene device is in a really quiet, really dark environment, would it harvest any energy or not?’ The conventional answer to that is no, as it apparently defies the laws of physics. But the physics had never been looked at carefully. I think people were afraid of the topic a bit because of Feynman. So, everybody just said, ‘I'm not touching that.’ But the question just kept demanding our attention. Honestly, its solution was only found through the perseverance and diverse approaches of our unique team.”
https://www.youtube.com/watch?v=ADtHfn3bAaM
Good Vibrations // University of Arkansas
University of Arkansas physics professor Paul Thibado has been studying graphene since its discovery in 2004. A single layer of carbon atoms arranged in a honeycomb lattice structure, graphene exists in a state of constant motion. Thibado’s breakthrough discovery was that the energy it produces from this motion could be harvested and stored in tiny batteries. These batteries are ideal for sensors embedded in hard-to-access places, such as underground pipe systems or interior aircraft cable ducts. The power these batteries provide is clean and potentially limitless.
https://www.youtube.com/watch?v=GYzsB55mfjE
Representation of Nonlinear Thermal Current
https://journals.aps.org/pre/abstract/10.1103/PhysRevE.108.024130
Charging capacitors from thermal fluctuations using diodes
P. M. Thibado,, et al.
[ PDF ]
Abstract -- We theoretically consider a graphene ripple as a Brownian particle coupled to an energy storage circuit. When circuit and particle are at the same temperature, the second law forbids harvesting energy from the thermal motion of the Brownian particle, even if the circuit contains a rectifying diode. However, when the circuit contains a junction followed by two diodes wired in opposition, the approach to equilibrium may become ultraslow. Detailed balance is temporarily broken as current flows between the two diodes and charges storage capacitors. The energy harvested by each capacitor comes from the thermal bath of the diodes while the system obeys the first and second laws of thermodynamics.
https://bpb-us-e1.wpmucdn.com/wordpressua.uark.edu/dist/3/316/files/2025/03/entropy.pdf
Transient Thermal Energy Harvesting at a Single Temperature Using Nonlinearity
T.B. Amin, J.M. Mangum, Md R. Kabir, S.M. Rahman, Ashaduzzaman, P. Kumar, L.L. Bonilla, and P.M. Thibado
[ PDF ]
Abstract: The authors present an in-depth theoretical study of two nonlinear circuits capable of transient thermal energy harvesting at one temperature. The first circuit has a storage capacitor and diode connected in series. The second circuit has three storage capacitors, and
two diodes arranged for full wave rectification. The authors solve both Ito–Langevin and Fokker–Planck equations for both circuits using a large parameter space including capacitance values and diode quality. Surprisingly, using diodes one can harvest thermal energy at a single temperature by charging capacitors. However, this is a transient phenomenon. In equilibrium, the capacitor charge is zero, and this solution alone satisfies the second law of thermodynamics. The authors found that higher quality diodes provide more stored charge and longer lifetimes. Harvesting thermal energy from the ambient environment using diode nonlinearity requires capacitors to be charged but then disconnected from the circuit before they have time to discharge.
https://bpb-us-e1.wpmucdn.com/wordpressua.uark.edu/dist/3/316/files/2025/02/vcm.pdf
Journal of Low Power Electronics and Application 15, 11 (2025).
Low-Level Kinetic-Energy-Powered Temperature Sensing System
Ashaduzzaman, J.M. Mangum, S.M. Rahman, T.B. Amin, Md R. Kabir, H. Do, G. Carichner, D. Blaauw, and P.M. Thibado
[ PDF ]
Abstract: Powering modern nanowatt sensors from omnipresent low-level kinetic energy: This study investigates the power levels produced by a varying-capacitance kinetic energy harvesting system. A model system consisting of a uniformly driven rotating capacitor was built to develop an accurate output power performance model. We found a quantitative linear relationship between the rectified output current and the input applied bias voltage, driving frequency, and capacitance variation. We also demonstrate that our variable capacitor system is equivalent to fixed capacitor driven with an alternating current power source. Both the fixed-capacitance and varying-capacitance energy harvesting systems recharge a three-volt battery, which in turn powers a custom ultralow-power-consuming temperature sensor system.
https://thibado.uark.edu/files/2024/12/energy24.pdf
Array of Graphene Solar Cells on 100 mm Silicon Wafers for Power Systems
S.M. Rahman, Md R. Kabir, T.B. Amin, J.M. Mangum, Ashaduzzaman, and P.M. Thibado
[ PDF ]
Abstract: High electrical conductivity and optical transparency make graphene a suitable candidate for photovoltaic-based power systems. In this study, we present the design and fabrication of an array of graphene-based Schottky junction solar cells. Using mainstream semiconductor manufacturing methods, we produced 96 solar cells from a single 100 mm diameter silicon wafer that was precoated with an oxide layer. The fabrication process involves removing the oxide layer over a select region, depositing metal contacts on both the oxide and bare silicon regions, and transferring large-area graphene onto the exposed silicon to create the photovoltaic interface. A single solar cell can provide up to 160 μA of short-circuit current and up to 0.42 V of open-circuit voltage. A series of solar cells are wired to recharge a 3 V battery intermittently, while the battery continuously powers a device. The solar cells and rechargeable battery together form a power system for any 3-volt low-power application.
https://bpb-us-e1.wpmucdn.com/wordpressua.uark.edu/dist/3/316/files/2017/05/aip_ad_eh.pdf
Physical Review E 102, 042101 (2020)
Fluctuation-induced current from freestanding graphene
P.M. Thibado, P. Kumar, S. Singh, M. Ruiz-Garcia, A. Lasanta, and L.L. Bonilla
[ PDF ]
ABSTRACT -- e present five circuit topologies for low power energy harvesting. The most efficient circuit uses a variable capacitor as the power source, a DC bias voltage to charge the variable capacitor, two transistors for rectification, and two storage capacitors. Varying the capacitance performs work and results in stored charge in the capacitors. We experimentally measure the storage capacitor voltage and current over time. The circuit efficiency nears 50% at a maximum power of 10 nW. Multiple circuit topologies are simulated and yield efficiencies from 15% to 50%
DEVICE FOR AMBIENT THERMAL AND VIBRATION ENERGY HARVESTING -- US11705756
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An integrated circuit on a chip may include a plurality of capacitors that are connected in series and generate an AC noise signal. A selected bandwidth of the AC noise signal transmits through the series of capacitors as a first AC power signal. Respective rectifiers are positioned for receiving a positive cycle of the first AC power signal and a negative cycle of the first AC power signal. Output terminals are connected to the respective rectifiers and configured for connection to an off chip circuit. The capacitors may be fixed or variable gap capacitors.
ENERGY HARVESTING DEVICES AND SENSORS, AND METHODS OF MAKING AND USE THEREOF -- US12163508
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Tool and method for in situ vapor phase deposition source material reloading and maintenance -- US6551405
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A tool and method for reloading source materials in a vapor phase deposition (VPD) environment is disclosed. The tool and method does not require the venting of the VPD environment in order to perform its functions. The tool may reload source material into effusion cells or electron beam cells of a molecular beam epitaxy (MBE) machine without venting the growth chamber.