Relationship between structural rigidity and quantum efficiency in phosphors for solid state lighting

Our article on “An integrated first principles and experimental investigation of the relationship between structural rigidity and quantum efficiency in phosphors for solid state lighting” has just been published in the Journal of Luminescence. This work is a collaborative effort between the McKittrick and Ong groups, and Jungmin Ha and Zhenbin Wang are co-first authors. In this work, we test the hypothesis of whether high host structural rigidity results in phosphors with high quantum efficiency, and show using an integrated approach that combines DFT calculations and experimental studies that a high Debye temperature alone is not a sufficient condition for a high quantum efficiency.

Upcoming talks at XXV International Materials Research Congress

Prof Ong and Zhenbin Wang will be giving the following talks at the upcoming XXV International Materials Research Congress held in Cancun, Mexico. Shyue Ping Ong, “Multi-Electron Polyanion Cathodes For High Energy Density Alkali-Ion Batteries”, Symposium B4. Materials and technologies for stationary electrochemical energy storage, Wed Aug 17 2016, 8:30am. Zhenbin Wang, “Discovery of Novel Narrow-Band Red Phosphors using High-Throughput First Principles Descriptors”, Symposium B2. Inorganic Luminescent Materials and Applications, Thurs, Aug 18 2016, 12:45 pm. We look forward to meeting fellow scientists and researchers who are there!

Dopant segregation and embrittlement at Mo grain boundaries

Richard Tran and Zihan Xu published their paper on “Computational study of metallic dopant segregation and embrittlement at Molybdenum grain boundaries” in Acta Materialia. Mo and its alloys are important refractory materials for high temperature applications, but suffer from low ductility. In this work, we investigated the segregation and strengthening effects of 29 metallic dopants using DFT and empirical continuum models. We show that dopant chemistry and site preference plays a significant role in segregation behavior and strengthening effects at the GBs that deviate from simple bond-breaking arguments. Ta, Re, Os and W are predicted to have a weak strengthening effect on Mo for the Σ5(310) tilt GB, and Mn, Fe, Co and Nb are predicted to have reasonable strengthening effects for the Σ5(100) twist GB. Check out the paper at our publications page.

pymatgen 4.0.0 released

Version 4.0.0 of pymatgen has just been released. This new version cleans up a lot of the old deprecated code, and includes a lot of new functionality such as ABINIT8 support, improved lammps analysis, and many bug fixes. Check it out at