Over the past eight years, there has been a steady and appreciable increase in power conversion efficiency of organometal halide perovskite solar cells. The relatively high efficiency of these solar cells combined with their ability to be processed using simple solution-based methods, make perovskite solar cells a promising candidate as a solar energy solution. However, perovskite solar cells suffer from a lack of mechanical reliability and chemical stability especially compared to existing solar technologies like silicon, cadmium telluride, and copper indium gallium diselenide devices.
To help improve the chemical instabilities of perovskite solar cells, I am working on the development of thin film barrier layers which prevent degradation by inhibiting the diffusion of water and the volatilization of the perovskite itself in elevated temperatures. We use atmospheric, open-air plasma deposition in order to deposit our thin film barriers, as it is a scalable process, which uses chemical radicals and UV light to deposit high quality, dense films at lower temperatures. The eventual goal is to ensure that the efficiency of the solar cell does not drop below 90% of its initial efficiency after 1000 hours in an 85oC and 85% relative humidity environment.
Another research area I am actively exploring is building flexible perovskite solar cells on metal foil substrates. Flexible substrates are an ideal fit for a roll-to-roll processing line which is necessary for scaling up the manufacturing of solar cells. Metal foil substrates also offer the added advantage of retaining its mechanical integrity in a much larger temperature window than other flexible polymer substrates. The larger temperature window is very useful because many layers in a standard perovskite solar cell device stack require processing at temperatures > 300oC. By developing an efficient perovskite device architecture on metal foil, we are making progress towards enabling perovskite solar cells as a viable solution for solar energy.
- Liu, J.; Wang, J.; Zhang, Z.; Molina-Lopez, F.; Wang, G.J.; Schroeder, B.; Yan, X.; Zeng, Y.; Zhao, O. et al. Fully stretchable active-matrix organic light-emitting electrochemical cell array. Nature Communication 2020.
- Zhao, O.; Ding, Y.; Pan, Z.; Rolston, N.; Zhang, J.; Dauskardt, R. H. Open-Air Plasma-Deposited Multilayer Thin Film Moisture Barriers. ACS Appl. Mater. Interfaces 2020. https://doi.org/10.1021/acsami.0c01493.
- Printz, A. D.; Zhao, O.; Hamann, S.; Rolston, N.; Solgaard, O.; Dauskardt, R. H. Self-Aligned Concentrating Immersion-Lens Arrays for Patterning and Efficiency Recovery in Scaffold-Reinforced Perovskite Solar Cells. Appl. Mater. Today 2020, 20, 100704. https://doi.org/10.1016/j.apmt.2020.100704.
- Gutwald, M.; Rolston, N.; Printz, A. D.; Zhao, O.; Elmaraghi, H.; Ding, Y.; Zhang, J.; Dauskardt, R. H. Solar Energy Materials and Solar Cells Perspectives on Intrinsic Toughening Strategies and Passivation of Perovskite Films with Organic Additives. Sol. Energy Mater. Sol. Cells 2020, 209, 110433. https://doi.org/10.1016/j.solmat.2020.110433.
- Moriche, R.; Ding, Y.; Dong, S.; Zhao, O.; Dauskardt, R. H. Tunable Structure and Connectivity of Organosilica Hybrid Films by Using Different Epoxy Based Precursors in Atmospheric Plasma Deposition. Appl. Surf. Sci. 2020, 508 (December 2019), 145233. https://doi.org/10.1016/j.apsusc.2019.145233.
- William J Scheideler, Nicholas Rolston, Oliver Zhao, Jinbao Zhang, Reinhold H Dauskardt, “Rapid Aqueous Spray Fabrication of Robust NiOx: A Simple and Scalable Platform for Efficient Perovskite Solar Cells,” Advanced Energy Materials, 2019. DOI: https://doi.org/10.1002/aenm.201803600
- Bateman, Zhao, Bajcsy, Jennings, Toth, Cohen, Horton, Khattar, Kuo, Lee, Lim, Migasiuk, Renganathan, Zhang, and Oliveira “A User-Centered Design and Analysis of an Electrostatic Haptic Touchscreen System for Students with Visual Impairments,” International Journal of Human-Computer Studies, 2017, 109, 102-111. DOI: https://doi.org/10.1016/j.ijhcs.2017.09.004
- Alexander C. Kozen, Chuan-Fu Lin, Oliver Zhao, Sang Bok Lee, Gary W. Rubloff, and Malachi Noked. “Stabilization of Lithium Metal Anodes by Hybrid Artificial Solid Electrolyte Interphase,” Chemistry of Materials, 2017, 29 (15), 6298-6307. DOI: 10.1021/acs.chemmater.7b01496
- Chuan-Fu Lin, Malachi Noked, Alexander C. Kozen, Chanyuan Liu, Oliver Zhao, Keith Gregorczyk, Liangbing Hu, Sang Bok Lee, and Gary W. Rubloff, “Solid Electrolyte Lithium Phosphous Oxynitride as a Protective Nanocladding Layer for 3D High-Capacity Conversion Electrodes.” ACS Nano, 2016, 10, 2693−2701
- Luo, W., Lin, C.-F., Zhao, O., Noked, M., Zhang, Y., Rubloff, G. W. and Hu, L. (2016), “Ultrathin Surface Coating Enables the Stable Sodium Metal Anode.” Adv. Energy Mater., 1601526. doi:10.1002/aenm.201601526
- Horton, Renganathan, Toth, Cohen, Bajcsy, Bateman, Jennings, Khattar, Kuo, Lee, Lim, Migasiuk, Zhang, Zhao, and Oliveira, “A Review of Principles in Design and Usability Testing of Tactile Technology for Individuals with Visual Impairments.” Assistive Technology 2016.
- O. Zhao, P. Thornton, Z. Pan, & R.H. Dasukardt, “New Concepts for Reliable Low-Cost Module Encapsulation and Barrier Technologies” Photovoltaic Reliability Workshop, Denver, CO, Feb 26, 2020.
- O. Zhao, P. Thornton, Y. Ding, & R.H. Dasukardt, “Demonstrating New Concepts for Reliable Low-Cost Module Encapsulation and Barrier Technologies” DuraMAT 2019 Fall Workshop, Avon, CO, Aug 27, 2019.
- O. Zhao, A.D. Printz, S.S. Hamann, N. Rolston, O. Solgaard, & R.H. Dauskardt, “Self-aligned Concentrating Immersion Lens Arrays for Patterning and Efficiency Recovery in Scaffold-Reinforced Perovskite Solar Cells” Materials Research Society Spring Meeting, Phoenix, AZ, April 25, 2019.
- O. Zhao, A.D. Printz, N. Rolston, S.S. Hamann, O. Solgaard, & R.H. Dauskardt, “Multifunctional lens arrays for patterning and photon management in compound perovskite solar cells” eWear Symposium, Stanford, CA, September 13, 2018.
- A. Printz, N. Rolston, S.S. Hamann, O. Zhao, O. Solgaard, & R.H. Dauskardt, “Scaffold-reinforced perovskite compound solar cells with integrated light management”, Materials Research Society Spring Meeting, Phoenix, AZ, April 6, 2018.
- 2018 NSF GRFP Fellow