Vertical Organic Thin Film Transistor for Skin Gas Sensing
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Solution Overview
Problem
Traditional organic field-effect transistors (OFETs) suffer from low current output due to intrinsically low carrier mobility and instability, primarily because of weak wavefunction overlap between molecules and disorders in the thin film, which limits their operating frequency and makes them susceptible to environmental factors.
Innovation Solution
The development of high-current organic thin film transistor (OTFT) devices with vertically-designed structures and donor-acceptor-based organic semiconductor materials, featuring a vertical gas sensor with a substrate, collector and emitter layers, and a metal grid with openings, utilizing polyvinylpyrrolidone as an insulating layer and specific organic semiconductor compounds to enhance mobility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional horizontal OFET structure is used, then device fabrication is simplified, but current output is low due to low carrier mobility
Solution Approach 1:
The patent transitions from a traditional horizontal OFET structure to a vertical transistor architecture. This dimensional change allows the channel to extend vertically through multiple layers (emitter, organic semiconductor layer, collector), enabling higher current density and improved carrier mobility while maintaining ease of fabrication through standard layer deposition techniques.
2Volume of moving object
If thin conduction channels are used, then device size is reduced, but stability deteriorates due to sensitivity to adsorbed oxygen and moisture
Solution Approach 1:
The patent employs a composite structure consisting of multiple functional layers: an emitter layer, an organic semiconductor layer, and a collector layer, separated by a dielectric layer. This multi-layer composite architecture provides both compact size and enhanced stability by controlling interfaces and protecting the conduction channel from environmental contaminants while maintaining efficient charge transport.
3Productivity
If operating voltage is increased to achieve desired current output, then current density improves, but energy consumption increases
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: the vertical channel length, layer thicknesses, material composition of the organic semiconductor layer, and electrode configurations. These parameter changes enable the device to achieve high current density at reduced operating voltages, improving efficiency by decoupling current output from proportional energy consumption increases.
4Speed
If donor-acceptor-based organic semiconductor materials are used, then carrier mobility is enhanced, but material complexity increases
Solution Approach 1:
The patent implements donor-acceptor-based organic semiconductor materials specifically in the active channel region where charge transport occurs, while other structural layers use simpler materials. This localized application of complex materials optimizes carrier mobility where needed without unnecessarily complicating the entire device structure, maintaining manufacturability while achieving high performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These OTFT devices achieve high relative current density at low voltages, improving sensitivity and stability, enabling effective detection of gases emitted from the skin with sensitivity to ammonia and aldehydes, and potentially offering non-invasive health monitoring solutions.
Implementation Method 1
the OSC layer is disposed in the vertical nano-channels configured to adsorb the gas emitted from skin
Implementation Method 2
an organic semiconductor (OSC) layer located in between the collector and emitter
Data Source
AI summary
A device for analyzing gas emitted from skin includes: an enclosure for collecting the gas emitted from skin, the enclosure having: an inlet through which a carrier gas is flown; and an outlet through which the carrier gas and the gas emitted from skin is flown into a vertical gas sensor, such that the vertical gas sensor has: a substrate; a collector layer; an emitter layer positively biased relative to the collector; a metal grid with a metal layer having openings, the metal grid located in between, but not in direct contact with, the collector and emitter; and an organic semiconductor (OSC) layer located in between the collector and emitter.