[Coming soon in January 2022]

Wang Materials Group
@​ McKetta Department of Chemical Engineering, The University of Texas at Austin

Computational Engineering of Optoelectronic Materials

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Our group utilizes and deploys computational methods to engineer the optical, electronic, and transport properties of materials in energy sustainability technologies. Enabled by high performance computing (HPC), we seek to elucidate and predict the materials properties at the microscopic level using first-principles calculations, drive the exploration of novel materials platforms, and create strategies that directly couple to experiments. In particular, we look to understand and harness defects in materials for optoelectronic devices. Research in the group is highly interdisciplinary and draws upon fields such as chemical engineering, materials science, and solid-state physics.

Current research goals are focused on catalysis, energy conversion, and next-generation computing applications.

Throughout our research and teaching efforts, we strive to create and foster a diverse, equitable, and inclusive environment.

Research Projects

Mixed transition metal systems
in electrocatalysts

Hydrogen fuel is considered to be a strong candidate to replace fossil fuels. Water splitting via electrolysis is a promising avenue for generating hydrogen fuel in an efficient manner. The transition metal oxyhydroxides  (MOOH, M = Fe, Ni, Co, ...) have been shown to have one of the highest activities of all known electrocatalysts. Interestingly, only certain compositions of transition metals have shown enhanced electrocatalytic performance. Furthermore, many of these systems are known to structurally change after cycling in operation. Nevertheless, there is limited understanding as to how or why performance is so dependent on composition and structure.

Our goal is to elucidate the microscopic impact of the presence of mixed transition metals on charge transfer (1) and charge recombination (2), and rationalize structure-composition-property-relationships.
Past relevant papers:
  • H. Ma, W. Wang, S. Kim, M.H. Cheng, M. Govoni, G. Galli. “PyCDFT: a Python package for constrained density functional theory.” J. Comp. Chem. 41, 1859 (2020) [doi: 10.1002/JCC.26354] [open-source code]
  • W. Wang, Y. Kang, H. Peelaers, K. Krishnaswamy, C.G. Van de Walle. “First-principles study of transport in WO3.” Phys. Rev. B. 101, 045116 (2020). [doi: 10.1103/PhysRevB.101.045116]
  • W. Wang, H. Peelaers, J.X. Shen, A. Janotti, C.G. Van de Walle. “Impact of point defects on electrochromism in WO3.” Proc. SPIE 10533, Oxide-based Materials and Devices IX; 10533C (2018), [doi:10.1117/12.2303688]

Chemoselectivity in aqueous environments for
(photo)electrochemical systems

Harnessing solar energy to drive water splitting reactions is a sustainable and clean strategy to hydrogen generation. In order to realize a hydrogen economy at scale and avoid stressing freshwater resources, we must look to using ocean/sea water.  However, ocean/sea water contains a medley of salts and ions, in particular chloride ions, that can inhibit water-splitting reactions and corrode the active material. Many multicomponent systems have shown the ability to split water in a salty aqueous environment, but no systematic understanding of which features of material systems work or why exists.

Thus our goal is to establish a holistic picture of the interfacial interactions between semiconductor surfaces and (salty) aqueous environments and their impact on electronic structure and provide engineering guidelines for more robust systems capable of selective and efficient generation of water splitting reactions.
Past relevant papers:
  • D. Lee,* W. Wang*, C, Zhou *, X. Tong, M. Liu, G. Galli, K.-S. Choi. “The impact of surface composition on the interfacial energetics and photoelectrochemical properties of BiVO4 .” Nature Energy. 6, 287 (2021)[doi: 10.1038/s41560-021-00777-x] [UChicago News release][BNL news release]
  • A. Lindberg*, W. Wang*, S. Zhang, G. Galli, K.-S. Choi. “Can a PbCrO4 photoanode perform as well as isoelectronic BiVO4?” ACS Appl. Energy Mater. (2020) [doi: 10.1021/acsaem.0c01250]
  • W. Wang, P. Strohbeen, D. Lee, C. Zhou, J. Kawasaki, K.-S. Choi, M. Liu, G. Galli. “The role of surface oxygen vacancies in BiVO4.” Chemistry of Materials. 32, 2899-2909 (2020). [doi: 10.1021/acs.chemmater.9b05047]

Oxygen vacancies and electric fields in perovskites for neuromorphic computing

As conventional materials such as silicon are approaching quantum mechanical limits, a new paradigm beyond Moore’s law is needed. One promising solution is neuromorphic computing, which aims to develop devices based on our own brain capable of learning and making nuanced decisions. Neurons operate with up to a 1000 times smaller power dissipation compared to devices based on conventional semiconductors, and thus offer a sustainable model for the next-generation of computing infrastructure. 

We study the migration of oxygen vacancies and how this changes in the presence of an external field in perovskite compounds as one way to achieve memristive behavior (i.e., the resistance depends on the previous state of the system). Perovskites offer fantastic compositional and structural variations, and will help elucidate fundamental aspects of metal-to-insulator transitions.
Past relevant papers:
  • W. Wang, P. Strohbeen, D. Lee, C. Zhou, J. Kawasaki, K.-S. Choi, M. Liu, G. Galli. “The role of surface oxygen vacancies in BiVO4.” Chemistry of Materials. 32, 2899-2909 (2020). [doi: 10.1021/acs.chemmater.9b05047]
  • W. Wang, A. Janotti, C.G. Van de Walle. “Phase transformations upon doping in WO3.” J. Chem. Phys., 146, 214504 (2017), [doi: 10.1063/1.4984581]
  • W. Wang, A. Janotti, C.G. Van de Walle. “Role of oxygen vacancies in crystalline WO3.” J. Mat Chem. C, 4, 6641 – 6648 (2016), [doi: 10.1039/C6TC01643J]

Past Projects Gallery

Interested students and postdocs, please reach out to: wwwwennie [at] austin.utexas.edu

The University of Texas at Austin 
McKetta Department of Chemical Engineering