DOI: 10.5281/zenodo.7920055
title: Dataset for: "Additively manufactured degradable piezoelectric microsystems for sensing and actuating"

description: Dataset for "Additively manufactured degradable piezoelectric microsystems for sensing and actuating"
Morgan Monroe1,2, Nicolas Fumeaux1, L. Guillermo Villanueva2, and Danick Briand1
1Soft Transducers Laboratory (LMTS), EPFL, Switzerland
morgan.monroe@epfl.ch, danick.briand@epfl.ch
2Advanced NEMS Laboratory (A-NEMS), EPFL, Switzerland
 
This data set contains the data collected during the FNS project Green Piezo (Grant no. 179064) in association with the recent publication entitled "Additively manufactured degradable piezoelectric microsystems for sensing and actuating" 
DOI: 10.1002/admt.202300745
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Manuscript Abstract: 
The increasing global overabundance of electronic waste and concerns regarding the energy and material-intensive processes associated with traditional electronics manufacturing is driving the development of solution processed, degradable electronics. In particular, solution processed, degradable piezoelectrics have widespread potential in sustainable electronics, due to their diverse use in both sensing and actuating applications and the current industry predominance of lead-based materials. Yet current eco-friendly multi-material printing processes are limited by both the conventional challenges of multilayer process integration as well as the low-temperature thermal constraints of biodegradable materials. In this study, we present a novel approach to the fabrication of additively manufactured and sustainable piezoelectric devices made with degradable electrode materials on paper substrates. The screen-printed, eco-friendly KNbO3 piezoelectric transducers are combined with degradable carbon- or zinc-based conductive inks. We evaluate the physical, dielectric, and piezoelectric properties of the devices, assessing the influence of electrode material on device performance. We report on effective piezoelectric coefficients as high as 4.6 pC N-1 and 5.1 pC N-1 for printed piezoelectric devices on paper substrates with carbon and zinc electrodes respectively. We then demonstrate the applicability of the developed technology in both sensing and actuating applications. Thus, we present the first instance of sustainable fully additively manufactured piezoelectric force sensors and acoustic speakers. By demonstrating entirely printable piezoelectric devices compatible with various green electrode materials, we work to develop more complex sustainable printed piezoelectric technologies in the future.
 
The data set consists of the following folders:

Device design files
Physical characterization data
Dielectric characterization data
Force Sensor Demonstrator data
Speaker Demonstrator data
Below is a detailed description of the data types and contents of each folder. In many files, the naming convention includes one of two key material indicators. In reference to ink properties, the term "Ink Active Material" indicates the primary ingredient in the ink being characterized. This is either KNbO3, Zinc, or Carbon. The specific ink compositions can be found in the Methods portion of the associated manuscript. In reference to devices being characterized, the term "Electrode Material" indicates the primary component of the printed or deposited electrode layers of the devices (as the piezoelectric layer is always the printed KNbO3 film). The electrode materials are either "Gold" (referring to thermally evaporated Gold of approximately 100nm thickness) which was used as a reference electrode material, "Zinc" (referring to screen printed zinc ink as described in the manuscript), or "Carbon" (Referring to screen printed carbon ink as described in the manuscript).
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Data types
There are 13 file types in this data set: .pdf, .png, .tif, .txt, .dat, .csv, .svg, .stl, .py, .vi, .dwf3work, .aup3, .wav

.pdf files 

pdf files in this repository contain summaries of images used in physical characterization, aggregated for ease of visualization. These are exported from Photoshop files and thus include full image information.
.png and .tif files 

These files contain scanning electron microscopy images of the printed samples on silicon, in cross-section.
.txt, .csv, and .dat files 

These files contain raw data from device characterization. These file types are comma delimited and the files can be opened with text editors such as Notepad++. Column headers elaborate on the data contained within each file.  
.svg files 

These files contain vector data displaying the full designs of devices fabricated in this study. This data can be opened with a vector graphics editor such as InkScape. The various layers of each file denote a different layer of the device design, and can be treated individually as masks for the relevant layers.
.stl files 

These files contain design information for 3D components. These files can be opened with any 3D design software such as FreeCAD. All .stl files included in this repository are reproduced from Shannon Ley (https://pinshape.com/items/36134-3d-printed-3d-printed-headphones).
.py files 

These files contain python scripts used to process the raw data after collection. These scripts can be opened and edited with standard python scripting interfaces. Each script is commented with descriptions of the overall file as well as in-line comments for user orientation. 
.vi files 

These files contain LabVIEW scripts used to collect raw data during measurements. These scripts can be opened and edited with LabVIEW from version 2020. The script is commented with descriptions of the overall file as well as in-line comments for user orientation. Only one file in this dataset is of this filetype.
.dwf3work files

These files contain Digilent Waveforms workspaces used to collect raw data during measurements. These scripts can be opened using the opensource Digilent Waveforms software (https://digilent.com/shop/software/digilent-waveforms/) to view the recorded data and all relevant recording parameters at time of measurement. 
.aup3 files 

These files contain Audacity workspaces used to collect and process audio data during speaker characterization measurements. These files can be opened using the opensource Audacity software (https://www.audacityteam.org/).
.wav files 

These files are audio files of the data exported from Audacity during speaker device characterization and can be opened with any audio processing software.
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01 Characterization Device Design
This folder contains the design files associated with the fabrication of the basic printed devices used for characterization studies.
01 CapacitorsALL.svg
A vector file containing the whole-device design of the capacitor style devices used in primary characterization. Each layer of the file is a layer of the device, and was used for the ordering and fabrication of associated screen printing meshes and shadowmasks.
02 BottomElectrode.svg
A vector file containing the design of solely the bottom electrode layer for devices used in primary characterization. This design was used for the ordering and fabrication of associated screen printing meshes and shadowmasks.
03 PiezoelectricLayer.svg
A vector file containing the design of solely the piezoelectric layer for devices used in primary characterization. This design was used for the ordering and fabrication of associated screen printing meshes and shadowmasks.
04 TopElectrode.svg
A vector file containing the design of solely the top electrode layer for devices used in primary characterization. This design was used for the ordering and fabrication of associated screen printing meshes and shadowmasks.
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02 Physical Characteristics
This folder contains all the data associated with characterizing the physical properties of the piezoelectric devices in this manuscript.
01 Particle Size Analysis
01 Images: A folder of SEM images as .png files. These images are cross-sectional SEM images of samples used to evaluate the particle size distribution for the KNbO3, Zinc, and carbon powders using in device fabrication. A second set of images with an appended filename ("traces") in the same folder portrays the sizing lines used to randomly sample particles for sizing.
02 ParticleSizeDistribution_RAW.csv: A data file containing the raw measurements collected using the above images in tandem with ImageJ processing software. Data was used to produce histograms of particle size distributions for the KNbO3, Zinc, and Carbon particles.
 
02 Profilometry
01 Profilometry Data: A folder of raw data collected as profilometry measurements in the form of .dat files. Data files are labelled using the convention "Profile_[Electrode Material]_DeviceStack_Sample[#].dat" (Ex: "Profile_Carbon_DeviceStack_Sample2.dat"). All measurements begin with a measure of the paper substrate as reference before approaching the sample, where it crosses all 3 layers of the sample before returning to the paper substrate, creating a series of layer-cake-like steps from which layer thicknesses can be determined.
02 ProfilometeryDataPlotter.py: a python script to batch import and plot the above collected raw profilometry data. 
 
03 Cross-section Optical Images
A folder containing optical microscopy images of the printed devices in cross-section when printed on paper substrates. The naming convention used is "Optical_[Electrode Material]_[microscope Magnification]_[Image number in that condition].tif" (Ex: "Optical_Carbon_x50_01.tif").
 
04 Cross-section SEM Images
A folder containing scanning electron microscopy ("SEM") images of the printed devices in cross-section when printed on silicon substrates. The naming convention used is "SEM_[Electrode Material]_[microscope Magnification]_[Image number in that condition].tif" (Ex: "SEM_Carbon_1k_01.tif").
 
05 Ink Rheology 
Summary data collected during rheological measurements of the KNbO3, Zinc, and Carbon inks, as .txt files. The naming convention is "Viscosity_[Ink Primary Component]Ink.txt" (Ex: "Viscosity_ZincInk.txt")
 
06 Degradation Study 
01 DegradationStudy_MassChange.csv: A data file containing the raw measurements collected during the degradation studies. Data includes the specific samples under test and their measured mass at specific dates, as measured after drying.
02 Degradation Study Images.pdf: a .pdf file containing the raw degradation images used in this study, correlated to the dates of imaging and text conditions. 
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03 Electrical Characteristics
This folder contains all the data associated with characterizing the dielectric and piezoelectric properties of the piezoelectric devices in this paper.
01 Impedance Data
01 ImpedanceDataAnalysis.py 
The python analysis script used to batch analyze and plot the raw impedance data collected for these samples. Takes the files in the associated folder as input and outputs arrays of measured capacitance and permittivity values for the data analyzed, as well as plots of the processed impedance data as a function of frequency.
02 Raw Impedance Data
The raw impedance data used to evaluate the dielectric properties of the devices, including two file types: 
".csv": Impedance data collected for capacitor style devices of each electrode type, in the after exporting the relevant impedance, phase, and capacitance data from the raw collection file format. Naming convention is "Impedance_[electrode material]_ALL.csv" (Ex: "Impedance_Carbon_ALL.csv").
 ".dwf3work": Raw Impedance data collected for capacitor style devices of each electrode type, in the original files as collected using Digilent Waveforms Software (open source). Data is split into two files based on the size of the capacitors being measured, (either 5 and 10 mm2 devices, or 20 and 30mm2 devices). The naming convention used is "Impedance_[Electrode Material]__[capacitor surface areas tested].dwf3work" (Ex: "Impedance_Zinc_5&10mm2.dwf3work").
 
02 Berlincourt Data
This folder contains all the data associated with characterizing the piezoelectric properties of the devices in this manuscript. It includes 3 files, sorted by the electrode material of the devices under test, and reports the average d33,eff values (over 3 repetitions) measured for those devices based on the applied poling Voltage and field. The naming convention used is "BerlincourtData_[Electrode Material].csv" (Ex: "BerlincourtData_Carbon.csv").
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04 Force Sensor Demonstrator
This folder contains all the data associated with force sensor demonstrator reported on in the associated manuscript.
01 TouchGrid.svg
A vector file containing the whole-device design of the force sensor device used in this sensing demonstration. Each layer of the file is a layer of the device, and was used for the ordering and fabrication of associated screen printing meshes.
 
02 VoltageMeasurement.vi
A LabView script file used for recording the output voltage of the piezoelectric devices as a function of time. To be used in combination with an Agilent 34410A or 34411A Multimeter. Outputs Voltage response as a function of time from the initiation of the recorded measurement.
 
03 Single Force Data
This folder contains data associated with characterizing the force sensor demonstrators reported on in this manuscript. It includes 3 sub-folders, sorted by the electrode material of the devices under test. The naming convention used for the sub-folders is "SingleForce_[Electrode Material]" (Ex: "SingleForce_Zinc"). Within each sub-folder is a series of data files (.csv) detailing the test and data conditions. Each sample was compressed with a set force in a series of pulses. The naming convention used for the files in the sub-folders is "[Electrode Material]_[Max Applied Force]_[MeasuredData].csv" (Ex: "Gold_12.5N_MM.csv"), where the measured data is either "_F" or "_MM" for Force data or Multimeter data respectively.
"_F.csv": The files include data recorded by the Instron Pull tester of the force applied to the sample as a function of time. This data is associated with the measured voltage in the paired "_MM.csv" file. 
"_MM.csv": The files include data recorded by a LabVIEW script in tandem with an Agilent multimeter of the voltage produced by the sample associated with the incident force in the paired "_F.csv" file. 
 
04 Stepped Force Data
This folder contains data associated with characterizing the force sensor demonstrators reported on in this manuscript. It includes 3 sub-folders, sorted by the electrode material of the devices under test. The naming convention used for the sub-folders is "SteppedMeasurements_[Electrode Material]" (Ex: "SteppedMeasurements_Gold"). Within each sub-folder is a series of data files (.csv) detailing the test and data conditions. Each sample was compressed with a series of pulses successively increasing in applied force. The naming convention used for the files in the sub-folders is "[Electrode MaterialSteppedSweep[#]_[MeasuredData].csv" (Ex: "Carbon_SteppedSweep1_F.csv"), where the measured data is either "_F" or "_MM" for Force data or Multimeter data respectively, and the # indicates the repetition number of that specific measurement. Other details are the same as those described above for the subfolder data of 03 Single Force Data.
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05 Speaker Demonstrator
This folder contains all the data associated with speaker demonstrator reported on in the associated manuscript.
01 Speaker Design
01 SpeakersBuzzers.svg 
A vector file containing the design of the components used to fabricate the piezoelectric buzzer for the speaker demonstrator. This includes a baseplate onto which the piezoelectric devices were adhered, two rings as standoffs, and two long traces used for the "contact wires". All components were lasercut from cardboard or cardstock components.
02 3D Design Files 
A folder containing the design files (.stl) for 3D printing of the headphone chassis, including the headband, ear cans, and baffles. All designs were provided open source by Shannon Ley (https://pinshape.com/items/36134-3d-printed-3d-printed-headphones).
 
02 Speaker Data
01 RawAudioRecordings 
A folder containing the raw audio recordings used in speaker characterization, in the form of .aup3 files, directly from the recording software (Audacity). File naming convention is "[Electrode Material]_[Device Size used]_[Recording sampling rate]_RAW.aup3" (Ex: "Zinc_5x30mm2_44.1khz_RAW.aup3").
02 Exported Audio 
A folder containing the exported audio recordings used in speaker characterization after trimming to a consistent length of 15s, and exporting from the recording software (Audacity) in the form of .wav files. Each sub-folder has naming convention of "[Electrode Material]_[Device Size used]_[Recording sampling rate]_export" (Ex: "Zinc_5x30mm2_44.1khz_export"), and contains a number of files. Each file within these folders is labelled with the frequency at which the speaker was actuated for that recording data. These files were then imported into Origin, where an FFT was used to extract the amplitude of the recorded data at that specific actuating frequency.
 
03 Speaker LDV
A folder containing the laser doppler vibrometry data collected for speakers with either Zinc or Carbon-electroded piezoelectric actuators. The data comes in two formats: as-produced from Digilent Waveforms (.dwf3work), or exported (.csv) files. The naming convention for the raw data is "[Electrode Material]_[Speaker active area]_LDV_Raw.dwf3work" (Ex: "Zinc_5x30mm2_LDV_Raw.dwf3work"). The naming convention for the exported data is "[Electrode Material]_[Speaker active area]_LDV_Export.csv" (Ex: "Zinc_5x30mm2_LDV_Export.csv").