Ali Shakouri | SMART Industry Consortium/Purdue University: Can mathematical models and image processing replace expensive vacuum deposition in printed electronics?
00:07:30.385 - 00:08:51.965
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Can mathematical models and image processing replace expensive vacuum deposition in printed electronics?
Screen printing conductive electrodes introduces microstructural variability, causing significant signal fluctuation in electrochemical sensors. For instance, testing a batch of 30 low-cost sensors in a single nitrate solution yields voltage variances of 50 to 60 millivolts, translating to an unacceptable 30% variability in performance. Traditionally, solving this requires transitioning to costly vacuum evaporated electrodes, which destroys the economic viability of disposable agricultural IoT devices.
Instead of upgrading the physical hardware, researchers can leverage inline optical and physical characterization at the point of manufacture. By coupling this structural data with a physics-based model of the electrode's temporal response, an image-processing algorithm can mathematically correct for the microstructural non-uniformities.
This hybrid approach of hardware-software co-design mitigates up to 80% of the inherent fabrication variability. As a result, the device-to-device variability drops from 30% to under 5% in laboratory environments without adding a single cent to the raw material or deposition costs of the roll-to-roll printed substrate.
In this short video, you can learn:
* How microstructural roughness in screen-printed electrodes degrades the baseline sensitivity of ion-selective electrochemical sensors.
* Why physical modeling of electrochemical response curves outperforms raw hardware upgrades in low-cost manufacturing.
* The methodology for utilizing inline imaging data and algorithms to reduce device-to-device variability by over 80 percent.
๐ **Clip Abstract** Screen-printed electrochemical sensors suffer from high device-to-device variability due to microstructural roughness on printed electrodes and membranes. This clip demonstrates how combining inline optical characterization with a temporal physics-based model can mathematically calibrate out 80% of this variance, reducing device error to under 5% without expensive vacuum-deposition processes.
#ScreenPrintedElectrodes, #ElectrochemicalSensors, #HardwareSoftwareCoDesign, #InlineOpticalCharacterization, #PrintedElectronics, #AgriculturalIoT
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00:04:06.325 - 00:05:40.885
How can field-directed assembly transform cheap piezoelectric microparticles into highly transparent acoustic speakers?
How can field-directed assembly transform cheap piezoelectric microparticles into highly transparent acoustic speakers?
The fabrication of large-area, semi-transparent tactile and acoustic transducers depends heavily on controlling the orientation of active crystalline domains. By dispersing piezoelectric particles into a polymer matrix and applying external electric or magnetic fields during curing, researchers can force the vertical alignment of these particles perpendicular to the plane of the film. This field-directed self-assembly enables highly uniform, flexible piezoelectric sheets manufactured over large areas at a fraction of the cost of sputtered ceramic thin films.
The resulting anisotropic microstructures possess extraordinary mechanical-to-electrical transduction sensitivity. They are capable of resolving forces down to the milligram range, such as detecting the impact of a microscopic droplet or a single bird feather. Because the underlying physical mechanism of piezoelectricity is thermodynamically reversible, these exact same thin-film sheets can function in reverse as acoustic actuators.
By applying high-frequency AC voltages across the film, the inverse piezoelectric effect drives localized micro-vibrations, transforming the flexible sheet into a highly directional, transparent speaker. This acoustic transducer demonstrates a flat frequency response stretching up to 20 kilohertz and delivers output sound pressures ranging between 60 and 70 decibels.
In this short video, you can learn:
* The process of using electric and magnetic fields to achieve vertical alignment of piezoelectric particles in polymeric thin films.
* How field-directed particle alignment yields high-sensitivity tactile interfaces capable of detecting sub-milligram physical forces.
* The acoustic properties and design limits of flexible, transparent speaker diaphragms utilizing the inverse piezoelectric effect up to 20 kHz.
๐ **Clip Abstract** Vertical alignment of piezoelectric particles in thin-film polymers can be achieved over large areas via electric and magnetic fields to create cheap, semi-transparent sensors. The speaker explains how these reversible transducer sheets can function both as ultra-sensitive touch sensors and as flexible, transparent acoustic speakers operating up to 20 kilohertz.
#FieldDirectedAssembly, #PiezoelectricComposites, #InversePiezoelectricEffect, #TransparentAcousticTransducers, #PrintedElectronics, #FlexibleAcoustics
00:09:49.655 - 00:11:10.495
Why do electrochemical sensors only become temperature-sensitive as they age, and how do we solve this mathematically in the field?
Why do electrochemical sensors only become temperature-sensitive as they age, and how do we solve this mathematically in the field?
Deploying low-cost electrochemical sensors in agricultural soils introduces severe environmental challenges, particularly diurnal temperature fluctuations that distort raw output voltage. Interestingly, fresh printed ion-selective sensors exhibit minimal thermal sensitivity; however, as the polymer membranes hydrate and age in soil over weeks, they develop a highly pronounced temperature dependency. Stabilizing the physical package with active thermal management is cost-prohibitive for disposable, distributed IoT nodes.
To overcome this age-dependent drift, researchers deploy a multi-sensor array at a single sensing node containing a mix of fresh and aged sensors. By understanding the underlying physics of membrane degradation and ion-exchange thermodynamics, we can model the relationship between temperature, sensor age, and the resulting electrochemical potential.
Applying a Maximum Likelihood Estimation (MLE) algorithm to the combined output of these co-located sensors allows the system to separate thermal noise from real concentration changes. This digital calibration pipeline successfully reconstructs the true nitrate dynamics over several weeks of field exposure, matching laboratory ground truth data without complex physical shielding.
In this short video, you can learn:
* Why printed electrochemical sensors develop a late-stage sensitivity to environmental temperature variations as they age in the field.
* How co-locating fresh and aged sensors in a single sensing node enables differential tracking of drift phenomena.
* The mathematical application of Maximum Likelihood Estimators to reconstruct raw electrochemical sensor data into precise chemical concentration metrics.
๐ **Clip Abstract** Environmental temperature variations degrade the signal integrity of aged electrochemical agricultural sensors, presenting a major barrier to low-cost field deployment. This segment details a software-calibration approach that combines multi-sensor array nodes with Maximum Likelihood Estimation to accurately reconstruct chemical concentration data despite severe thermal drift.
#PrintedElectrochemicalSensors, #IonSelectiveSensors, #MaximumLikelihoodEstimation, #SensorDriftCompensation, #PrecisionAgriculture, #SoilSensingIoT