Projects

• Printed and Flexible Energy Harvesting Devices
• Printed and Flexible Energy Storage Devices
• Printed Large-Area Electronics
• Printed Large-Area Optoelectronics
• Printed Large-Area Antennas
• Wearable Medical Devices
• Printed Sensors

Printed and Flexible Energy Harvesting Devices

Relevant publications:

1. 
   Flexible and stretchable power sources for wearable electronics Alla M. Zamarayeva, Aminy E. Ostfeld, Michael Wang, Jerica K. Duey, Igal Deckman, Balthazar P. Lechêne, Greg Davies, Daniel A. Steingart, and Ana Claudia Arias Science Advances, 2017 3, 6. [Abstract] [Bibtex] [PDF]

   Flexible and stretchable power sources represent a key technology for the realization of wearable electronics. Developing flexible and stretchable batteries with mechanical endurance that is on par with commercial standards and offer compliance while retaining safety remains a significant challenge. We present a unique approach that demonstrates mechanically robust, intrinsically safe silver-zinc batteries. This approach uses current collectors with enhanced mechanical design, such as helical springs and serpentines, as a structural support and backbone for all battery components. We show wire-shaped batteries based on helical band springs that are resilient to fatigue and retain electrochemical performance over 17,000 flexure cycles at a 0.5-cm bending radius. Serpentine-shaped batteries can be stretched with tunable degree and directionality while maintaining their specific capacity. Finally, the batteries are integrated, as a wearable device, with a photovoltaic module that enables recharging of the batteries.

   @article{zamarayeva2017flexible, author = {Zamarayeva, Alla M. and Ostfeld, Aminy E. and Wang, Michael and Duey, Jerica K. and Deckman, Igal and Lech{\^e}ne, Balthazar P. and Davies, Greg and Steingart, Daniel A. and Arias, Ana Claudia}, title = {Flexible and stretchable power sources for wearable electronics}, volume = {3}, number = {6}, year = {2017}, doi = {10.1126/sciadv.1602051}, publisher = {American Association for the Advancement of Science}, url = {http://advances.sciencemag.org/content/3/6/e1602051}, eprint = {http://advances.sciencemag.org/content/3/6/e1602051.full.pdf}, journal = {Science Advances}, thumbnail = {zamarayeva2017flexible.png}, pdf = {zamarayeva2017flexible.pdf} }

1. 
   Organic solar cells and fully printed super-capacitors optimized for indoor light energy harvesting Balthazar P. Lechene, Martin Cowell, Adrien Pierre, James W. Evans, Paul K. Wright, and Ana C. Arias Nano Energy , 2016 26, . [Abstract] [Bibtex] [PDF]

   Abstract Flexibility, lightness and printability make organic solar cells (OSC) strong candidates to power low consumption devices such as envisioned for the Internet of Things. Such devices may be placed indoors, where light levels are well below typical outdoors level. Here, we demonstrate that maximizing the efficiency of {OSC} for indoor operation requires specific device optimization. In particular, minimizing the dark current of the solar cells is critical to enhance their efficiency under indoor light. Cells optimized for sunlight reach 6.2% power conversion efficiency (PCE). However when measured under simulated indoor light conditions, the {PCE} is to 5.2%. Cells optimized for indoor operation yield 7.6% of {PCE} under indoor conditions. As a proof-of-concept, the solar cells are combined with fully printed super-capacitors to form a photo-rechargeable system. Such a system with a 0.475 cm2 indoor-optimized solar cell achieved a total energy conversion and storage efficiency (ECSE) of 1.57% under 1-sun, providing 26 mJ of energy and 4.1 mW of maximum power. Under simulated indoor light the system yielded an {ECSE} of 2.9%, while delivering 13.3 mJ and 2.8 mW. Those energy and power levels would be sufficient to power low-consumption electronic devices with low duty cycles.

   @article{lechene2016organic, title = {Organic solar cells and fully printed super-capacitors optimized for indoor light energy harvesting }, journal = {Nano Energy }, volume = {26}, number = {}, pages = {631 - 640}, year = {2016}, note = {}, issn = {2211-2855}, doi = {10.1016/j.nanoen.2016.06.017}, url = {http://www.sciencedirect.com/science/article/pii/S2211285516302002}, author = {Lechene, Balthazar P. and Cowell, Martin and Pierre, Adrien and Evans, James W. and Wright, Paul K. and Arias, Ana C.}, keywords = {Supercapacitor }, thumbnail = {lechene2016organic.png}, pdf = {lechene2016organic.pdf} }

Printed and Flexible Energy Storage Devices

Relevant publications:

1. 
   High-performance flexible energy storage and harvesting system for wearable electronics Aminy E. Ostfeld, Abhinav M. Gaikwad, Yasser Khan, and Ana C. Arias Scientific Reports, 2016 6, [Abstract] [Bibtex] [PDF]

   This paper reports on the design and operation of a flexible power source integrating a lithium ion battery and amorphous silicon solar module, optimized to supply power to a wearable health monitoring device. The battery consists of printed anode and cathode layers based on graphite and lithium cobalt oxide, respectively, on thin flexible current collectors. It displays energy density of 6.98_mWh/cm2 and demonstrates capacity retention of 90% at 3C discharge rate and  99% under 100 charge/discharge cycles and 600 cycles of mechanical flexing. A solar module with appropriate voltage and dimensions is used to charge the battery under both full sun and indoor illumination conditions, and the addition of the solar module is shown to extend the battery lifetime between charging cycles while powering a load. Furthermore, we show that by selecting the appropriate load duty cycle, the average load current can be matched to the solar module current and the battery can be maintained at a constant state of charge. Finally, the battery is used to power a pulse oximeter, demonstrating its effectiveness as a power source for wearable medical devices.

   @article{ostfeld2016high, title = {High-performance flexible energy storage and harvesting system for wearable electronics}, author = {Ostfeld, Aminy E. and Gaikwad, Abhinav M. and Khan, Yasser and Arias, Ana C.}, issn = {2045-2322}, journal = {Scientific Reports}, volume = {6}, year = {2016}, publisher = {Nature Publishing Group}, url = {http://www.nature.com/srep/2016/160517/srep26122/full/srep26122.html}, doi = {10.1038/srep26122}, thumbnail = {ostfeld2016high.png}, pdf = {ostfeld2016high.pdf} }

1. 
   Fabrication of a High-Performance Flexible Silver-Zinc Wire Battery Alla M. Zamarayeva, Abhinav M. Gaikwad, Igal Deckman, Michael Wang, Brian Khau, Daniel A. Steingart, and Ana Claudia Arias Advanced Electronic Materials, 2016 , . [Abstract] [Bibtex] [PDF]

   Fabrication of a flexible wire battery assembled by utilizing low-cost fabrication processes and based on silver-zinc chemistry is reported. It offers unique versatility in terms of integration with wearable technologies due to its omnidirectional flexibility and improved performance characteristics. The battery is stable over 170 cycles with capacity retention above 98% and has linear capacity ranging between 1.2 and 1.8 mAh cm_1 at 0.5C discharge rate.

   @article{zamarayeva2016fabrication, author = {Zamarayeva, Alla M. and Gaikwad, Abhinav M. and Deckman, Igal and Wang, Michael and Khau, Brian and Steingart, Daniel A. and Arias, Ana Claudia}, title = {Fabrication of a High-Performance Flexible Silver-Zinc Wire Battery}, journal = {Advanced Electronic Materials}, issn = {2199-160X}, volume = {}, number = {}, pages = {}, url = {http://dx.doi.org/10.1002/aelm.201500296}, doi = {10.1002/aelm.201500296}, keywords = {flexible batteries, flexible electronics, silver-zinc batteries, wire-shaped batteries}, year = {2016}, thumbnail = {zamarayeva2016fabrication.png}, pdf = {zamarayeva2016fabrication.pdf}, publisher = {Wiley-VCH} }

Printed Large-Area Electronics

Relevant publications:

1. All-Printed Flexible Organic Transistors Enabled by Surface Tension-Guided Blade Coating Adrien Pierre, Mahsa Sadeghi, Marcia M Payne, Antonio Facchetti, John E Anthony, and Ana Claudia Arias Advanced Materials, 2014 26, 32. [Bibtex]

   @article{pierre2014all, title = {All-Printed Flexible Organic Transistors Enabled by Surface Tension-Guided Blade Coating}, author = {Pierre, Adrien and Sadeghi, Mahsa and Payne, Marcia M and Facchetti, Antonio and Anthony, John E and Arias, Ana Claudia}, journal = {Advanced Materials}, volume = {26}, number = {32}, pages = {5722--5727}, year = {2014} }

1. 
   Identifying orthogonal solvents for solution processed organic transistors Abhinav M. Gaikwad, Yasser Khan, Aminy E. Ostfeld, Shishir Pandya, Sameer Abraham, and Ana Claudia Arias Organic Electronics, 2016 30, [Abstract] [Bibtex] [PDF] Solvents visualization program is available in the Downloads section.

   Abstract Identification of solvents for dissolving polymer dielectrics and organic semiconductors is necessary for the fabrication of solution-processed organic field effect transistors (OFETs). In addition to solubility and printability of a solvent, orthogonality is particularly important when forming multilayer structure from solutions. Currently, the process of finding orthogonal solvents is empirical, and based on trial-and-error experimental methods. In this paper, we present a methodology for identifying orthogonal solvents for solution-processed organic devices. We study the accuracy of Hildebrand and Hansen solubility theories for building solubility boundaries for organic semiconductor (Poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (PBTTT) and polymer dielectrics (Poly(methyl methacrylate) (PMMA), Polystyrene (PS)). The Hansen solubility sphere for the organic semiconductor and polymer gate dielectrics are analyzed to identify solvents that dissolve {PMMA} and PS, but are orthogonal to PBTTT. Top gate/bottom contact {PBTTT} based {OFETs} are fabricated with {PMMA} gate dielectric processed with solvents that are orthogonal and non-orthogonal to PBTTT. The non-orthogonal solvents swell the semiconductor layer and increase their surface roughness.

   @article{gaikwad2016identifying, title = {Identifying orthogonal solvents for solution processed organic transistors}, author = {Gaikwad, Abhinav M. and Khan, Yasser and Ostfeld, Aminy E. and Pandya, Shishir and Abraham, Sameer and Arias, Ana Claudia}, journal = {Organic Electronics}, volume = {30}, pages = {18 - 29}, year = {2016}, issn = {1566-1199}, url = {http://www.sciencedirect.com/science/article/pii/S1566119915302299}, doi = {10.1016/j.orgel.2015.12.008}, thumbnail = {gaikwad2016identifying.png}, pdf = {gaikwad2016identifying.pdf}, publisher = {}, note = {Solvents visualization program is available in the Downloads section.} }

Printed Large-Area Optoelectronics

Relevant publications:

1. 
   Charge-integrating organic heterojunction phototransistors for wide-dynamic-range image sensors Adrien Pierre, Abhinav Gaikwad, and Ana Claudia Arias Nature Photonics, 2017 [Abstract] [Bibtex] [PDF] Article

   Solution-processed phototransistors can substantially advance the performance of image sensors. Phototransistors exhibit large photoconductive gain and a sublinear responsivity to irradiance, which enables a logarithmic sensing of irradiance that is akin to the human eye and has a wider dynamic range than photodiode-based image sensors. Here, we present a novel solution-processed phototransistor composed of a heterostructure between a high-mobility organic semiconductor and an organic bulk heterojunction. The device efficiently integrates photogenerated charge during the period of a video frame then quickly discharges it, which significantly increases the signal-to-noise ratio compared with sampling photocurrent during readout. Phototransistor-based image sensors processed without photolithography on plastic substrates integrate charge with external quantum efficiencies above 100% at 100 frames per second. In addition, the sublinear responsivity to irradiance of these devices enables a wide dynamic range of 103 dB at 30 frames per second, which is competitive with state-of-the-art image sensors.

   @article{pierre2017charge, author = {Pierre, Adrien and Gaikwad, Abhinav and Arias, Ana Claudia}, title = {Charge-integrating organic heterojunction phototransistors for wide-dynamic-range image sensors}, journal = {Nature Photonics}, year = {2017}, month = feb, day = {20}, publisher = {Nature Publishing Group}, note = {Article}, issn = {1749-4893}, url = {http://dx.doi.org/10.1038/nphoton.2017.15}, thumbnail = {pierre2017charge.png}, pdf = {pierre2017charge.pdf} }

1. 
   Emission Area Patterning of Organic Light-Emitting Diodes (OLEDs) via Printed Dielectrics Donggeon Han, Yasser Khan, Karthik Gopalan, Adrien Pierre, and Ana C Arias Advanced Functional Materials, 2018 28, 37. [Abstract] [Bibtex] [PDF]

   Solution-processibility is one of the distinguished traits of organic light-emitting diodes (OLEDs) compared to existing solid-state LED technologies. It allows new opportunities which can simplify the fabrication and potentially reduce the cost of manufacturing process. Emission area patterning is one of the crucial fabrication steps and it usually involves subtractive methods, such as photolithography or etching. Here, printing techniques are used to pattern the emission area of blade-coated OLED layers. The print qualities of a number of printing schemes are characterized and compared. Spray coating and screen printing are used to deposit dielectrics with desired patterns on the OLED layers. At luminance of 1000 cd m_2 the OLEDs patterned using spray-coated and screen-printed dielectric show current density of 8.2 and 10.1 mA cm_2, external quantum efficiency (EQE) of 2.1% and 2.1%, and luminous efficacy of 5.5 and 6.3 lm W_1, respectively. The OLED characteristics and features of each printing scheme in depositing the dielectric layer are discussed. The printing methods are further applied to demonstrate displays with complex shapes and a seven-segment display.

   @article{han2018emission, title = {Emission Area Patterning of Organic Light-Emitting Diodes (OLEDs) via Printed Dielectrics}, author = {Han, Donggeon and Khan, Yasser and Gopalan, Karthik and Pierre, Adrien and Arias, Ana C}, journal = {Advanced Functional Materials}, volume = {28}, number = {37}, pages = {1802986}, year = {2018}, publisher = {Wiley Online Library}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.201802986}, thumbnail = {han2018emission.png}, pdf = {han2018emission.pdf} }

Printed Large-Area Antennas

Relevant publications:

1. 
   Printed Receive Coils with High Acoustic Transparency for Magnetic Resonance Guided Focused Ultrasound Joseph Corea, Patrick Ye, Dongjin Seo, Kim Butts-Pauly, Ana C. Arias, and Michael Lustig Scientific Reports, 2018 8, 3392. [Abstract] [Bibtex] [PDF]

   In magnetic resonance guided focused ultrasound (MRgFUS) therapy sound waves are focused through the body to selectively ablate difficult to access lesions and tissues. A magnetic resonance imaging (MRI) scanner non-invasively tracks the temperature increase throughout the tissue to guide the therapy. In clinical MRI, tightly fitted hardware comprised of multichannel coil arrays are required to capture high quality images at high spatiotemporal resolution. Ablating tissue requires a clear path for acoustic energy to travel but current array materials scatter and attenuate acoustic energy. As a result coil arrays are placed outside of the transducer, clear of the beam path, compromising imaging speed, resolution, and temperature accuracy of the scan. Here we show that when coil arrays are fabricated by additive manufacturing (i.e., printing), they exhibit acoustic transparency as high as 89.5%. This allows the coils to be placed in the beam path increasing the image signal to noise ratio (SNR) five-fold in phantoms and volunteers. We also characterize printed coil materials properties over time when submerged in the water required for acoustic coupling. These arrays offer high SNR and acceleration capabilities, which can address current challenges in treating head and abdominal tumors allowing MRgFUS to give patients better outcomes.

   @article{Corea2018AcousticTransparency, author = {Corea, Joseph and Ye, Patrick and Seo, Dongjin and Butts-Pauly, Kim and Arias, Ana C. and Lustig, Michael}, title = {Printed Receive Coils with High Acoustic Transparency for Magnetic Resonance Guided Focused Ultrasound}, journal = {Scientific Reports}, volume = {8}, number = {3392}, year = {2018}, month = feb, day = {21}, doi = {10.1038/s41598-018-21687-1}, publisher = {Nature Publishing Group}, url = {https://www.nature.com/articles/s41598-018-21687-1}, thumbnail = {Corea2018AcousticTransparency.png}, pdf = {Corea2018AcousticTransparency.pdf} }

1. 
   Screen-printed flexible MRI receive coils Joseph R Corea, Anita M Flynn, Balthazar Lechêne, Greig Scott, Galen D Reed, Peter J Shin, Michael Lustig, and Ana C Arias Nature Communications, 2016 7, [Abstract] [Bibtex] [PDF]

   Magnetic resonance imaging is an inherently signal-to-noise-starved technique that limits the spatial resolution, diagnostic image quality and results in typically long acquisition times that are prone to motion artefacts. This limitation is exacerbated when receive coils have poor fit due to lack of flexibility or need for padding for patient comfort. Here, we report a new approach that uses printing for fabricating receive coils. Our approach enables highly flexible, extremely lightweight conforming devices. We show that these devices exhibit similar to higher signal-to-noise ratio than conventional ones, in clinical scenarios when coils could be displaced more than 18_mm away from the body. In addition, we provide detailed material properties and components performance analysis. Prototype arrays are incorporated within infant blankets for in vivo studies. This work presents the first fully functional, printed coils for 1.5- and 3-T clinical scanners.

   @article{corea2016screen, title = {Screen-printed flexible MRI receive coils}, author = {Corea, Joseph R and Flynn, Anita M and Lech{\^e}ne, Balthazar and Scott, Greig and Reed, Galen D and Shin, Peter J and Lustig, Michael and Arias, Ana C}, journal = {Nature Communications}, volume = {7}, year = {2016}, publisher = {Nature Publishing Group}, url = {http://www.nature.com/ncomms/2016/160310/ncomms10839/full/ncomms10839.html}, doi = {110.1038/ncomms10839}, thumbnail = {corea2016screen.png}, pdf = {corea2016screen.pdf} }

Wearable Medical Devices

Relevant publications:

1. 
   A flexible organic reflectance oximeter array Yasser Khan, Donggeon Han, Adrien Pierre, Jonathan Ting, Xingchun Wang, Claire M. Lochner, Gianluca Bovo, Nir Yaacobi-Gross, Chris Newsome, Richard Wilson, and Ana C. Arias Proceedings of the National Academy of Sciences, 2018 [Abstract] [Bibtex] [PDF]

   The optical method to determine oxygen saturation in blood is limited to only tissues that can be transilluminated. The status quo provides a single-point measurement and lacks 2D oxygenation mapping capability. We use organic printed optoelectronics in a flexible array configuration that senses reflected light from tissue. Our reflectance oximeter is used beyond conventional sensing locations and accurately measures oxygen saturation on the forehead. In a full system implementation, coupled with a mathematical model, we create 2D oxygenation maps of adult forearms under pressure-cuff–induced ischemia. Our skin-like flexible sensor system has the potential to transform oxygenation monitoring of tissues, wounds, skin grafts, and transplanted organs.Transmission-mode pulse oximetry, the optical method for determining oxygen saturation in blood, is limited to only tissues that can be transilluminated, such as the earlobes and the fingers. The existing sensor configuration provides only single-point measurements, lacking 2D oxygenation mapping capability. Here, we demonstrate a flexible and printed sensor array composed of organic light-emitting diodes and organic photodiodes, which senses reflected light from tissue to determine the oxygen saturation. We use the reflectance oximeter array beyond the conventional sensing locations. The sensor is implemented to measure oxygen saturation on the forehead with 1.1% mean error and to create 2D oxygenation maps of adult forearms under pressure-cuff–induced ischemia. In addition, we present mathematical models to determine oxygenation in the presence and absence of a pulsatile arterial blood signal. The mechanical flexibility, 2D oxygenation mapping capability, and the ability to place the sensor in various locations make the reflectance oximeter array promising for medical sensing applications such as monitoring of real-time chronic medical conditions as well as postsurgery recovery management of tissues, organs, and wounds.

   @article{khan2018flexible, author = {Khan, Yasser and Han, Donggeon and Pierre, Adrien and Ting, Jonathan and Wang, Xingchun and Lochner, Claire M. and Bovo, Gianluca and Yaacobi-Gross, Nir and Newsome, Chris and Wilson, Richard and Arias, Ana C.}, title = {A flexible organic reflectance oximeter array}, year = {2018}, doi = {10.1073/pnas.1813053115}, publisher = {National Academy of Sciences}, issn = {0027-8424}, url = {http://www.pnas.org/content/early/2018/11/06/1813053115}, eprint = {http://www.pnas.org/content/early/2018/11/06/1813053115.full.pdf}, journal = {Proceedings of the National Academy of Sciences}, thumbnail = {khan2018flexible.png}, pdf = {khan2018flexible.pdf} }

1. 
   All-organic optoelectronic sensor for pulse oximetry Claire M Lochner*, Yasser Khan*, Adrien Pierre*, and Ana C Arias Nature Communications, 2014 5, 5745. [Abstract] [Bibtex] [PDF] *Equal contribution. Media Coverage: UC Berkeley Grad News, NSF Science 360 News, UC Berkeley News Center, Phys.org, ScienceDaily, and many more.

   Pulse oximetry is a ubiquitous non-invasive medical sensing method for measuring pulse rate and arterial blood oxygenation. Conventional pulse oximeters use expensive optoelectronic components that restrict sensing locations to finger tips or ear lobes due to their rigid form and area-scaling complexity. In this work, we report a pulse oximeter sensor based on organic materials, which are compatible with flexible substrates. Green (532_nm) and red (626_nm) organic light-emitting diodes (OLEDs) are used with an organic photodiode (OPD) sensitive at the aforementioned wavelengths. The sensor’s active layers are deposited from solution-processed materials via spin-coating and printing techniques. The all-organic optoelectronic oximeter sensor is interfaced with conventional electronics at 1_kHz and the acquired pulse rate and oxygenation are calibrated and compared with a commercially available oximeter. The organic sensor accurately measures pulse rate and oxygenation with errors of 1% and 2%, respectively.

   @article{lochner2014all, title = {All-organic optoelectronic sensor for pulse oximetry}, author = {Lochner*, Claire M and Khan*, Yasser and Pierre*, Adrien and Arias, Ana C}, journal = {Nature Communications}, volume = {5}, number = {5745}, year = {2014}, url = {http://www.nature.com/ncomms/2014/141210/ncomms6745/full/ncomms6745.html}, doi = {10.1038/ncomms6745}, thumbnail = {lochner2014all.png}, pdf = {lochner2014all.pdf}, publisher = {Nature Publishing Group}, note = {*Equal contribution. Media Coverage: }, media_1 = {UC Berkeley Grad News, }, media_1_link = {http://grad.berkeley.edu/news/headlines/engineering-team-invents-medical-sensor/}, media_2 = {NSF Science 360 News, }, media_2_link = {http://news.science360.gov/obj/story/d8f7fa4c-4e41-4bcb-8ccd-1939dc4af3da/organic-electronics-lead-cheap-wearable-medical-sensors}, media_3 = {UC Berkeley News Center, }, media_3_link = {http://newscenter.berkeley.edu/2014/12/10/organic-electronics-cheap-wearable-medical-sensors/}, media_4 = {Phys.org, }, media_4_link = {http://phys.org/news/2014-12-electronics-cheap-wearable-medical-sensors.html}, media_5 = {ScienceDaily, }, media_5_link = {http://www.sciencedaily.com/releases/2014/12/141210131356.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily%2Ftop_news+%28ScienceDaily%3A+Top+News%29}, media_6 = {and many more.}, media_6_link = {http://www.altmetric.com/details.php?domain=www.nature.com&citation_id=2972740} }

Printed Sensors

Relevant publications:

Last modified: 2022-04-12