화학공학소재연구정보센터
Solid State Ionics, Vol.253, 101-109, 2013
Tl-204 tracer diffusion and conductivity in thallium thiogermanate glasses
Conductivity and Tl-254 tracer diffusion measurements have been carried out in the (Tl2S)(x)(GeS)(60)(GeS2)(40-x) glassy system, where the Tl2S concentration changes between 0 <= x <= 25. The room temperature dc conductivity increases by 7 orders of magnitude with increasing thallium concentration, ranging between 10(-18) S cm(-1) for the 60GeS-40GeS(2) matrix and 10(-11) S cm(-1) for Tl2S-rich glasses. The activation energy decreases from 1.22 to 0.79 eV, respectively. The conductivity and thallium diffusion results reveal that the ionic transport becomes to be predominant at high thallium concentrations (approximate to 15 at.% Tl). The thallium ion transport number t(Tl-) increases from 10(-3) for low cation concentrations to t(Tl-) congruent to 1 for the x = 20 sample. The Haven ratio, H-R approximate to 1, indicates uncorrelated ion motion even at rather high thallium concentrations. The obtained results are discussed in comparison with similar (Ag2S)(x)(GeS)(60)(GeS2)(40-x), glassy system. (C) 2013 Elsevier B.V. All rights reserved.