Structure of semiconducting versus fast-ion conducting glasses in the Ag–Ge–Se system

What is it about?

The structural origin of the semiconductor to fast-ion conductor transition for glasses in the Ag-Ge-Se system is elucidated by employing a wide range of experimental techniques, including electric force microscopy, x-ray and neutron diffraction, and differential scanning calorimetry.

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Photo by Tyler Lastovich on Unsplash

Photo by Tyler Lastovich on Unsplash

Why is it important?

The onset of super-ionic conductivity in glassy materials is important for making electrolytes for battery or sensor applications, and for making novel forms of non-volatile computer memory. In our paper we employ a range of techniques to probe the structural origin of the semiconductor to fast-ion conductor transition for glasses in the Ag-Ge-Se system. A self-consistent picture emerges in which the material is phase separated, and where the onset of super-ionic behaviour is associated with the percolation of an ionically conducting Ag-rich phase. The structure of this phase evolves with composition as the addition of silver eliminates Se-Se homopolar bonds that originate from the base glass. The results should be of general interest to those keen on probing the structure of heterogeneous disordered materials, and understanding how this structure is related to the material properties.

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