Related Experiment Video
Updated: Jun 17, 2025
10:44
Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors
Published on: January 31, 2025
550
Bistable organic electrochemical transistors: enthalpy vs. entropy
Lukas M Bongartz1, Richard Kantelberg2, Tommy Meier2
1IAPP Dresden, Institute for Applied Physics, Technische Universität Dresden, Nöthnitzer Str. 61, 01187, Dresden, Germany. lukas.bongartz@tu-dresden.de.
Nature Communications
|August 9, 2024
Summary
A new thermodynamic model explains bistable operation in organic electrochemical transistors (OECTs) using enthalpy and entropy. This understanding enables the creation of single-OECT Schmitt triggers for advanced computing.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Organic Electronics
Background:
- Organic electrochemical transistors (OECTs) are crucial for bioelectronics and neuromorphic computing due to their electronic and ionic charge carrier coupling.
- Significant hysteresis in OECT transfer curves enables non-volatile memory applications, but its physical origin remains unclear.
Purpose of the Study:
- To develop a thermodynamic framework explaining the physical origin of bistable operation in OECTs.
- To validate the proposed model and explore its implications for OECT physics and device applications.
Main Methods:
- Development of a thermodynamic model based on enthalpy and entropy.
- Temperature-resolved characterizations and material manipulation.
- Thermal imaging and analysis of subthreshold swing deviations from Boltzmann statistics.
Main Results:
- The thermodynamic framework successfully explains bistable OECT operation through enthalpy-entropy interplay.
- Deviations from Boltzmann statistics in subthreshold swing were identified and analyzed.
- Existing literature on OECT hysteresis was reinterpreted in light of the new model.
Conclusions:
- A fundamental understanding of OECT hysteresis and bistability is established.
- The findings pave the way for novel device designs, including single-OECT Schmitt triggers.
- This work advances OECT physics for non-conventional computing paradigms leveraging symmetry-breaking phenomena.
Related Concept Videos
02:31Phase Transitions
19.0K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
19.0K
01:18Entropy
2.6K
The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the entropy.
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
2.6K
02:23Gibbs Free Energy and Thermodynamic Favorability
6.7K
The spontaneity of a process depends upon the temperature of the system. Phase transitions, for example, will proceed spontaneously in one direction or the other depending upon the temperature of the substance in question. Likewise, some chemical reactions can also exhibit temperature-dependent spontaneities. To illustrate this concept, the equation relating free energy change to the enthalpy and entropy changes for the process is considered:
6.7K
01:10Entropy Change in Reversible Processes
2.5K
In the Carnot engine, which achieves the maximum efficiency between two reservoirs of fixed temperatures, the total change in entropy is zero. The observation can be generalized by considering any reversible cyclic process consisting of many Carnot cycles. Thus, it can be stated that the total entropy change of any ideal reversible cycle is zero.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
2.5K
02:38Third Law of Thermodynamics
18.6K
A pure, perfectly crystalline solid possessing no kinetic energy (that is, at a temperature of absolute zero, 0 K) may be described by a single microstate, as its purity, perfect crystallinity,and complete lack of motion means there is but one possible location for each identical atom or molecule comprising the crystal (W = 1). According to the Boltzmann equation, the entropy of this system is zero.
18.6K
01:22Entropy within the Cell
10.5K
A living cell's primary tasks of obtaining, transforming, and using energy to do work may seem simple. However, the second law of thermodynamics explains why these tasks are harder than they appear. None of the energy transfers in the universe are completely efficient. In every energy transfer, some amount of energy is lost in a form that is unusable. In most cases, this form is heat energy. Thermodynamically, heat energy is defined as the energy transferred from one system to another that...
10.5K