Thermopower Enhancement in Designer Oxide Superlattices
August 12, 2014 — A layer-by-layer design of 2D oxide superlattices with precisely controlled interface compositions has improved the thermopower of oxide thermoelectrics by 300% compared to that of bulk counterparts. Controlling the 2D carrier density through a new materials design strategy is critical for developing highly efficient thermoelectrics.
Structure-dependent Properties Guide Catalyst Design for Oxygenates Conversion
August 06, 2014 — The catalytic transformation of oxygenates (i.e. aldehydes, alcohols, ketones) on metal oxides to generate value added products such as fuels and additives is of great importance industrially, yet is not well-understood. ORNL researchers have provided new insights into how oxygenates react on metal oxide particles with well-defined structures.
Pulsed Laser Deposition of Photoresponsive Two-Dimensional GaSe Nanosheet Networks
July 31, 2014 — Researchers demonstrated a pulsed laser deposition (PLD) approach to synthesize networks of interconnected metal chalcogenide (GaSe) nanosheets that exhibit high photoresponsivity.
Cooperative Growth of Large Single-Crystal Graphene Islands
June 12, 2014 — Researchers showed that it is possible to grow large, single-crystal graphene islands by controlling the nucleation density, which determines the growth mechanism.
Atom Substitution Gives Stable Performance of Solid Electrolytes
May 07, 2014 — The substitution of Ge for As in Li3AsS4 results in an exceptionally stable ionic conductivity versus temperature, and enhances the ionic conductivity by two orders of magnitude. The performance of solid state batteries is dramatically sensitive to temperature due to the energy barrier associated with Li ion motion.
Origin of anomalous atomic vibrations in efficient thermoelectrics revealed
May 06, 2014 — Thermoelectric SnTe and PbTe compounds were investigated with inelastic neutron scattering (INS) and first-principles calculations to understand the basis of their anharmonic lattice dynamics. The phonon anharmonicity of these materials is of both fundamental importance and of practical interest.
A Bi-Functional Electrolyte Design for Long Lasting Batteries
April 24, 2014 — An innovative design of a bi-functional electrolyte defies the theoretical maximum energy capacity of conventional lithium carbon fluoride (Li-CFx) batteries. This novel design has the potential of enabling the creation of long lasting batteries for implantable medical devices, wearable electronics and other applications.
Light-emitting diodes from monolayer WSe2 p-n junctions
April 24, 2014 — Light emitting diodes (LEDs) with improved efficiency have been realized using monolayers of WSe2 carefully cleaved from high-quality bulk single crystals. This new development has the potential for applications in novel optoelectronic devices, such as on-chip lasers.
Decoding the Resistivity of Solid Electrolytes for Batteries
April 02, 2014 — The atomic-scale origin of grain-boundary (GB) resistance in solid electrolytes has been revealed by electron microscopy and spectroscopy. Inorganic solid electrolytes have the potential for enabling intrinsically safe, energy-dense batteries.
New Composite Electrolyte for Advanced Solid State Batteries Shows that Two is Better than One
February 26, 2014 — A new composite electrolyte for batteries with high conduction has been made by combining two solid electrolytes with complementary properties. The composite optimizes the favorable properties of the individual components while minimizing their limitations and opens the door for the development of new solid-state batteries for energy-dense storage of electricity.