Scalable Processing of Reliable Perovskite Solar Cells
Hybrid perovskites have established themselves as the leading materials for next-generation thin film solar cells by widely outperforming competing organic photovoltaics and amorphous silicon. Because perovskites utilize earth-abundant elements and can be manufactured by scalable solution-processes such as spray coating and printing, they represent a potentially low-cost and high-performance PV technology. However, the mechanical fragility of perovskites, along with related chemical instability and moisture sensitivity, threaten to limit the scaling of this promising technology. We are working to simultaneously address the reliability and scaling of perovskite technology to large area modules with long service lifetimes.
Gravure Printing Scalable Transparent Electronics
Printing technologies are attractive methods for high-throughput additive manufacturing of nanomaterials-based thin film electronics. Roll-to-roll compatible techniques such as gravure printing can operate at high-speed (1-10 m/s) and high-resolution (< 10 um) to drive down manufacturing costs and produce higher quality flexible electronic devices, respectively. However, the large-scale deployment of printed wireless sensors, flexible displays, and wearable electronics, requires greater understanding of the printing physics of nanomaterial-based inks, in order to improve the resolution, reliability, and uniformity of printed systems. In the past, gravure-printed electronics was limited to printing polymeric organic inks and metal nanoparticles, but a detailed understanding of the physics of gravure printing can inform inorganic sol-gel ink design and extend the scope of high-speed printing to new high-performance inorganic materials including transparent conductive oxides (TCOs).
Material Design for Low-Temperature Processed Metal Oxides
Transparent metal oxides are one of the most promising material systems for thin-film flexible electronics due to their unique balance of optical transparency and high electron mobility. Rapid progress in the field of solution-processed metal oxides has established them as a leading material system for thin-film transistors, transparent window electrodes, and inorganic charge transport layers in thin film solar cells. Fully-integrating metal oxides with additive printing technologies can enable a range of applications such as flexible displays, UV-imaging systems, and low-power gas sensors that are not viable with incumbent manufacturing technologies. An understanding of the interactions between precursor chemistry, fluid properties, printed feature morphology, and electrical performance can advance the scalable fabrication of metal oxides using high-speed printing and offer high performance at a low thermal budget for applications on flexible polymer substrates.
- W.J. Scheideler, M. McPhail, R. Kumar, J. Smith, and V. Subramanian, "Scalable, High-Performance Printed InOx Transistors Enabled by UV-Annealed Printed High-k AlOx Gate Dielectrics" ACS Appl. Mater. Interfaces, (Under Review).
- A. Zeumault, W. Scheideler, and V. Subramanian, "Electrostatic Tuning of Spray-Deposited ZnO for Controlled Mobility Enhancement," Adv. Func. Mater, 10.1002/adfm.201701021, June 2017.
- W.J. Scheideler, R. Kumar, A. Zeumault, and V. Subramanian, "Low-Temperature-Processed Printed Metal Oxide Transistors Based on Pure Aqueous Inks," Adv. Func. Mater, 27, 1606062, Mar. 2017. *Featured in Advanced Science News: http://www.advancedsciencenews.com/aqueous-printed-low-temperature-transistors/
- S. Chung, M. A. U. Karim, H. J. Kwon, W. Scheideler, and V. Subramanian, “A High-Speed Inkjet-Printed Microelectromechanical Relay With a Mechanically Enhanced Double-Clamped Channel-Beam,” J. Microelectromechanical Syst., vol. PP, no. 99, pp. 1–7, 2016.
- W. J. Scheideler, J. Smith, I. Deckman, A.C. Arias, and V. Subramanian, “A Robust, Gravure Printed, Silver Nanowire/Metal Oxide Hybrid Electrode for High-Throughput Patterned Transparent Conductors,” J. Mater. Chem. C., vol. 4, no. 15, pp. 3248-3255, 2016.
- V. Subramanian, S. Chung, G. Grau, and W.J. Scheideler, "Printed Transistors and MEMS for Large-Area Electronics," SID Symposium Digest of Technical Papers, vol. 47, 1, 956-959, 2016.
- R. Kitsomboonloha, H. Kang, G. Grau, W.J. Scheideler, and V. Subramanian, “MHZ-Range Fully Printed Hig8Performance Thin-Film Transistors by Using High-Resolution Gravure-Printed Lines,"Adv. Electron. Mater., vol. 1, no. 12, Dec.. 2015.
- W. J. Scheideler, J. Jang, M. A. U. Karim, R. Kitsomboonloha, A. Zeumault, and V. Subramanian, “Gravure Printed Sol–Gels on Flexible Glass: A Scalable Route to Additively Patterned Transparent Conductors,” ACS Appl. Mater. Interfaces, vol. 7, no. 23, pp. 12679–12687, Jun. 2015.
- G. Grau, W. J. Scheideler, and V. Subramanian, “High-resolution gravure printed lines: proximity effects and design rules,” SPIE Organic Photonics + Electronics, 2015, vol. 9569, p. 95690B–95690B–8.
- A. Zeumault*, W. Scheideler*, G. Grau, J. Smith, and V. Subramanian, “Patterning of Solution-Processed, Indium-Free Oxide TFTs by Selective Spray Pyrolysis,” Adv. Electron. Mater., vol. 2, no. 2, Feb. 2015. (*Equal Contribution)
- W. J. Scheideler and C.-H. Chen, “The minimum flow rate scaling of Taylor cone-jets issued from a nozzle,” Appl. Phys. Lett., vol. 104, no. 2, p. 024103, Jan. 2014.
- Y. Xu, C. Liu, W. Scheideler, S. Li, W. Li, Y.F. Lin, F. Balestra, G. Ghibaudo, and K. Tsukagoshi, “Understanding Thickness-Dependent Charge Transport in Pentacene Transistors by Low-Frequency Noise,” IEEE Electron Device Lett., vol. 34, no. 10, pp. 1298–1300, Oct. 2013.
- C. Liu, Y. Xu, Y. Li, W. Scheideler, and T. Minari, “Critical Impact of Gate Dielectric Interfaces on the Contact Resistance of High-Performance Organic Field-Effect Transistors,” J. Phys. Chem. C, vol. 117, no. 23, pp. 12337 12345, Jun. 2013.
- Y. Xu, W. Scheideler, C. Liu, F. Balestra, G. Ghibaudo, and K. Tsukagoshi, “Contact Thickness Effects in Bottom-Contact Coplanar Organic Field-Effect Transistors,” IEEE Electron Device Lett., vol. 34, no. 4, pp. 535 537, Apr. 2013.
Conference Proceedings and Presentations
- W. J. Scheideler and V. Subramanian, “Improving High-Speed Nanomaterials Printing with Sub-Process Decoupled Gravure Printer Design,” Proceedings of ASME SMASIS (Smart Materials, Adaptive Structures, and Intelligent Systems), Snowbird, Utah, September, 2017.
- W. J. Scheideler and V. Subramanian, “UV-Annealing-Enhanced Stability in High-Performance Printed InOx Transistors,” Proceedings of IEEE Electron Devices Technology and Manufacturing Conference, Toyama, Japan, February, 2017.
- W.J. Scheideler, A. Zeumault, and V. Subramanian, “Engineering high-k LaxZr1-xOy dielectrics for high performance fully-solution-processed transparent transistors,” Proceedings of 2015 Device Research Conference, Columbus, OH, June. 2015.
*Indicates Presenting Author
- S. Patel*, W.J. Scheideler, M. Karim, and Vivek Subramanian, “Inkjet-Printed MEM Relays for Active Solar Cell Routing,” IEEE International Conference on Micro Electro Mechanical Systems, Jan., 2018.
- Y. Kobayashi*, W.J. Scheideler, and V. Subramanian, “Back-Channel Engineering of Ultrathin Printed Indium Oxide Transistors for Carbon Dioxide,” Poster Presentation at Materials Research Society Fall Meeting, Boston, MA, Dec., 2017 (Accepted).
- W. J. Scheideler* and V. Subramanian, “Improving High-Speed Nanomaterials Printing with Sub-Process-Decoupled Gravure Printer Design,” Oral Presentation at ASME SMASIS (Smart Materials, Adaptive Structures, and Intelligent Systems), Snowbird, Utah, September, 2017.
- J. Jang*, S. Chung, and W.J. Scheideler, “Printed Metal Oxide Devices,” IMID 2017 International Meeting on Information Display, Busan, Korea, Aug. 2017.
- P.R. Schunk*, K. Tjiptowidjojo, R. Malakhov, N. Bell, A. Cook, V. Subramanian, W. Scheideler, “Challenges in gravure and ink-jet printing of nano-colloidal inks,” IUTAM/AMERIMECH Symposium on Computational Mechanics of Particle-Functionalized Fluid and Solid Materials for Additive Manufacturing and 3D Printing Processes, Berkeley, CA, May 30, 2017.
- W. J. Scheideler* and V. Subramanian, “UV-Annealing-Enhanced Stability in High-Performance Printed InOx Transistors,” Poster Presentation at IEEE Electron Devices Technology and Manufacturing Conference, Toyama, Japan, February, March, 2017.
- W. J. Scheideler,* A.R. Zeumault, J. Smith, and V. Subramanian, “Aqueous-Processed Metal Oxide Conductors for High-Performance, Low Temperature, Printed Transistors,” Oral Presentation at Materials Research Society Fall Meeting, Boston, MA, November, 2016.
- G. Grau*, W.J. Scheideler, and V. Subramanian, “Fluid Mechanical Proximity Effects in High-Resolution Gravure Printing for Printed Electronics,” Oral Presentation at the 2016 Meeting of the American Physical Society’s Division of Fluid Dynamics, Portland, OR, Nov. 2016.
- W.J. Scheideler*, A.R. Zeumault, J.N. Smith, and V. Subramanian, “Precision Maskless Patterning of Indium-Free Metal Oxide TFTs by selective spray pyrolysis,” Oral Presentation at Materials Research Society Spring Meeting, Phoenix, AZ, April. 2016.
- W.J. Scheideler*, G. Grau, and V. Subramanian, “Designing Inorganic Sol-gel Metal Oxide Inks for Gravure Printed Transparent, High-Performance Electronics,” Oral Presentation at 2016 LOPEC International Printed Electronics Conference, Munich, Germany, April. 2016.
- W.J. Scheideler*, A. Zeumault, and V. Subramanian, “Engineering high-k LaxZr1-xOy dielectrics for high-performance fully-solution-processed transparent transistors,” Oral Presentation at 2015 Device Research Conference, Columbus, OH, June. 2015.
- W.J. Scheideler* and V. Subramanian, “Direct Patterning of Sol-Gel-Enhanced Silver Nanowire Electrodes by Gravure Printing,“ Oral Presentation at Materials Research Society Spring Meeting, San Francisco, CA, Apr. 2015.
- W.J. Scheideler*, J. Jang, and V. Subramanian, “Gravure-Printing Transparent Sol-Gel Conductors on Flexible Glass Substrates,” Poster Presentation at the Fall Materials Research Society Meeting, Boston, MA, Dec. 2014.
- W.J. Scheideler* and C.H. Chen, “The Minimum Flow Rate Scaling in Taylor Cone Jets,” Oral Presentation at the 2012 Meeting of the American Physical Society’s Division of Fluid Dynamics, San Diego, CA, Nov. 2012.
- UC Berkeley EECS Chair’s Excellence Award
- National Science Foundation Graduate Research Fellowship
- Angier B. Duke Memorial Scholarship