Vertical organic electrochemical transistor pairs
Inventors
Rivnay, Jonathan • Rashid, Reem B. • Ciechowski, Robert J.
Assignees
Publication Number
US-12336361-B2
Publication Date
2025-06-17
Expiration Date
2041-03-05
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Abstract
Cofacial vertical organic electrochemical transistor (vOECT) pairs, electronic circuits into which the vOECT pairs are integrated, and methods for fabricating the vOECT pairs are provided. The vOECTs pairs are formed from a vertically stacked structure that includes a first layer of an electrically conducting material, a first layer of an electrically insulating material, and a second layer of an electrically conducting material. The vOECTs of the pairs are formed on opposing sidewalls of a trench formed in the stacked structure.
Core Innovation
The invention provides cofacial vertical organic electrochemical transistor (vOECT) pairs formed from a vertically stacked structure that includes a first electrically conducting layer, a first electrically insulating layer, and a second electrically conducting layer. A trench is formed vertically through these layers, and a film of active material spans both conducting layers on each side of the trench. This film, when combined with an electrolyte within the trench and a gate electrode in contact with the electrolyte, creates a pair of vOECTs sharing a common active channel.
The problem being solved centers on limitations of traditional planar OECTs and previously fabricated vOECTs. Planar OECTs require large area due to lateral contact configuration, and earlier vertical OECTs, fabricated by traditional photolithography, suffered from parasitic capacitance due to overlap of active material on contacts, leading to slow response times. Additionally, creating complementary inverters using planar devices consumed significant real estate and required separately patterned channels for different semiconducting materials, imposing complex fabrication demands and limiting scalability.
Through the use of a vertically structured stack and the formation of a trench with a self-aligned method or photolithography, the invention enables fabrication of compact vOECT pairs with minimal overlap of active material and contacts, reducing parasitic capacitance. The design supports both complementary inverter and differential amplifier circuit configurations, facilitates the use of ambipolar semiconductors for balanced n-type and p-type functionality, and allows for large-scale integration as active components in various circuit architectures.
Claims Coverage
The patent claims cover five main inventive features as defined by the independent claims.
Cofacial vertical organic electrochemical transistor pair with vertically stacked structure and bisected trench
A device comprising: - A vertically stacked structure that includes a first electrically conducting layer, a second electrically conducting layer, and a separating electrically insulating layer. - A trench extending vertically through the stack, bisecting one or both conducting layers. - A film of active material in the trench spanning both conducting layers on either side. - An electrolyte at least partially filling the trench. - A gate electrode in contact with the electrolyte.
Electronic circuit incorporating cofacial vertical electrochemical transistor pair as an active component
An electronic circuit structure in which the previously described cofacial vertical organic electrochemical transistor pair forms an integrated active component of the circuit.
Complementary inverter formed with vertically stacked structure, trench, and specific electrical connections
A complementary inverter device comprising: - A vertically stacked structure with a first and a second electrically conducting layer, and an interposed insulating layer. - A trench vertically bisecting the first conducting layer, but not the second. - A film of active material in the trench as described. - An electrolyte partially filling the trench and a gate electrode in contact. - A voltage source connected to one part of the first conducting layer and ground connected to another part.
Differential pair with vertically stacked structure, bisected trench, and voltage/ground connections
A differential pair configuration comprising: - The same vertically stacked structure with first and second conducting layers separated by insulation. - A trench vertically bisecting the first conducting layer, but not the second. - A film of active material in the trench spanning layers. - An electrolyte within the trench and a gate electrode in contact. - A voltage source across the bisected first conducting layer and ground to the second conducting layer.
Method for forming a vertical organic electrochemical transistor
A method that includes: 1. Forming a vertically stacked structure with layered conducting and insulating materials and a hydrophobic capping layer. 2. Creating a trench in a central portion of the structure extending downward from the capping layer. 3. Depositing a liquid containing organic active material in the trench. 4. Evaporating the liquid to form a film of the active material spanning the trench and both conducting layers. 5. Filling the trench with electrolyte and placing a gate electrode in electrical communication with the organic active material.
In summary, the claims cover the structural design of cofacial vOECT pairs, their use within electronic circuits including inverters and differential amplifiers, and the specific method of fabrication enabling these devices.
Stated Advantages
The vertical structure results in a more compact form factor compared to planar OECTs, allowing the inverter active area to match the footprint of a single planar OECT.
The configuration enables high amplification, with shorter channel lengths leading to higher transconductance and improved electrical properties.
By minimizing overlap of the active material with contacts and reducing parasitic capacitance, the device achieves faster response times.
The fabrication approach enables simpler and potentially scalable manufacturing, including via self-aligned and laser-cut methods suitable for flexible and large-area electronics.
The design allows for the integration of complementary inverter and differential pair circuits as active components, suitable for low-power and high-gain on-site analog signal amplification.
The use of an ambipolar active material allows both n-type and p-type functionality in the same device structure, avoiding the need for separate patterning of different semiconductor materials.
The structure is compatible with flexible substrates and can be fabricated without the use of traditional photolithography for the trench, allowing for more versatile processing options.
Documented Applications
Active components in electronic circuits, including use in complementary inverters and differential pairs.
Analog voltage preamplifiers for recording electrocardiogram (ECG) signals.
On-site signal processing functions such as rectification and reference-based differential biochemical detection on flexible and conformal bioelectronic arrays.
Sensing measurement with internal reference/control in bioelectronics.
Potential use in logic circuits such as decoders for more complex circuit integration.
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