Interface-Driven Thermo-Electric Switching Performance of VO$^+$ Diffused Soda-Lime Glass.

Strongly confined NaVO$^+$ segregation and its thermo-responsive functionality at the interface between simple sputter-deposited amorphous vanadium oxide thin films and soda-lime glass was substantiated in the present study by in-situ temperature-controlled Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The obtained ToF-SIMS depth profiles provided unambiguous evidence for a reversible transformation that caused systematic switching of the NaVO$^+$/ Na$^+$ and Na$^+$/ VO$^+$ intensities upon cycling the temperature between 25 $^\circ$C and 340 $^\circ$C. Subsequently, NaVO complexes were found to be reversibly formed (at 300 $^\circ$C) in vanadium oxide diffused glass, leading to thermo-responsive electrical behaviour of the thin film glass system. This new segregation -- and diffusion-dependent multifunctionality of NaVO$^+$ -- points towards applications as an advanced material for thermo-optical switches, in smart windows or in thermal sensors.