Author: FirstCoder

Announcements

We are hiring!

We are seeking to fill one postdoctoral position. Successful candidates will have the opportunity to lead exciting projects that integrate advanced first principles methods, information technology and experiments (through external collaborations) to develop novel materials in energy storage and solid-state lighting. They will also receive mentoring to prepare them for future careers in academia or industry, including project management skills, proposal writing and effective scientific communication. More information can be found at http://www.materialsvirtuallab.org/positions. The ideal candidate should demonstrate creativity, passion for scientific inquiry, and an ability to link fundamental science to real-world applications. The ideal candidate will also have: An advanced degree in materials science and/or solid-state physics. Experience with first principles methods, such as density functional theory (DFT), ab initio molecular dynamics, density functional perturbation theory or GW. Programming skills, preferably with experience in sustainable software development for robust widely used code bases. Interested applicants should send the following materials to ongsp@ucsd.edu. A cover letter of no more than one page summarizing their research accomplishments and interests Curriculum vitae (Optional, but recommended) Samples of scientific codes they have written, either as a web link to a publicly accessible software repository or an email attachment.

Publications

Structure-Property-Composition Relations in β-SiAlON:Eu2+ Phosphor

Our work on “Elucidating Structure–Composition–Property Relationships of the β-SiAlON:Eu2+ Phosphor” has been published in Chemistry of Materials. Using first-principles calculations, we identified and confirmed various chemical rules for Si−Al, O−N, and Eu activator ordering in β-SiAlON, one of the most promising narrow-band green phosphors for high-power light-emitting diodes and liquid crystal display backlighting with wide color gamut. Through the construction of energetically favorable models based on these chemical rules, we studied the effect of oxygen content and Eu2+ activator concentrations on the local EuN9 activator environment, and its impact on important photoluminescence properties such as emission peak position (using the band gap as a proxy), bandwidth, and thermal quenching resistance.  Based on these insights, we discuss potential strategies for further composition optimization of β-SiAlON.

Publications

Thermodynamic scale of inorganic crystalline metastability

Prof Ong is a co-author on a recent article in Science Advances on the thermodynamic scale of inorganic crystalline metastability. This article uses the Materials Project, its API and pymatgen to perform a large-scale data-mining study of the thermodynamic scale of metastability for 29,902 observed inorganic crystalline phases. Press release is available on EurekAlert.

News

Ocean Discovery Institute

Professor Ong gave a talk on careers in STEM to 5th grade students from Hamilton Elementary at the Ocean Discovery Institute last Fri (Oct 14, 2016). He also worked with on building remotely operated vehicles. Check out the pictures below!

Publications

Room-Temperature All-solid-state Na-ion Batteries with Cl-doped Na3PS4

In collaboration with the Laboratory of Energy Storage and Conversion (LESC), we have developed a room-temperature all-solid-state rechargeable sodium-ion battery utilizing a novel Cl-doped Na3PS4 superionic conductor. The Cl-doped tetragonal Na3PS4 solid electrolyte exhibits room-temperature Na+ conductivity exceeding 1 mS/cm, and an all-solid-state TiS2/t-Na3−xPS4−xClx/Na cell utilizing this solid electrolyte can be cycled at room-temperature at a rate of C/10 with a capacity of about 80 mAh/g over 10 cycles. We show that this excellent electrochemical performance is not only due to the high Na+ conductivity of the solid electrolyte, but also due to the effect that “salting” Na3PS4 has on the formation of an electronically insulating, ionically conducting solid electrolyte interphase. This work is published in Scientific Reports. The co-first authors are Iek-Heng Chu (MAVRL), Christopher S. Kompella (LESC) and Han Nguyen (LESC), and the corresponding authors are Professors Shirley Meng and Shyue Ping Ong.

Publications

Data-driven Methods for the Study and Design of Alkali Superionic Conductors

Our article on “Data-driven First Principles Methods for the Study and Design of Alkali Superionic Conductors” has been published in  Chemistry of Materials as part of an invited Methods and Protocols special topic. In this work, we provide a detailed exposition of the first principles techniques that can be used to design alkali superionic conductors, a topic of high current interest. Accompanying this article is a repository of well-documented Jupyter notebooks that allows any researcher to easily reproduce the analysis and apply the same techniques to other materials. The article is available online and the notebooks are available at the following Github repo.

Announcements, Publications

Crystalium released

We have published the world’s largest database of surface energies and Wulff shapes, dubbed Crystalium. A collaborative effort between the Materials Virtual Lab and the Materials Project, this new open-source database can help researchers design new materials for technologies in which surfaces and interfaces play an important role, such as fuel cells, catalytic converters in cars, computer microchips, nanomaterials and solid-state batteries. You can read more about it in the UCSD press release on EurekAlert! This work is published in Scientific Data as an open-access article, and Richard Tran, one of our undergraduate volunteers, is the first author.