Pure YH3-δ and Mg0.1Y0.9H 2.9-δ exhibit large differences in their thermochromic properties. Whereas the transmittance of YH3-δ decreases by 9% to 36%, in Mg0.1Y0.9H2.9-δ it decreases by 64% to 83% between 30°C and 160°C. This thermochromic effect is caused by hydrogen desorption upon temperature increase. The main difference between the two systems is that the face-centered-cubic to hexagonal-close- packed phase transition between YH2+δ and YH 3-δ is absent in Mg0.1Y0.9Hx, i.e., the YHx stays cubic for all 2≤x≤3. Because of this, there are no plateaus in the pressure-composition isotherms of Mg0.1Y 0.9Hx and the steepness of the optical transition upon hydrogen desorption increases drastically compared to pure YHx.
Thermochromic effect in YH3-δ and Mg0.1Y 0.9H2.9-δ / I.A.M.E. Giebels, S.J. Van Der Molen, R. Griessen, M. Di Vece. - In: APPLIED PHYSICS LETTERS. - ISSN 0003-6951. - 80:8(2002), pp. 1343-1345. [10.1063/1.1446993]
Thermochromic effect in YH3-δ and Mg0.1Y 0.9H2.9-δ
M. Di VeceUltimo
2002
Abstract
Pure YH3-δ and Mg0.1Y0.9H 2.9-δ exhibit large differences in their thermochromic properties. Whereas the transmittance of YH3-δ decreases by 9% to 36%, in Mg0.1Y0.9H2.9-δ it decreases by 64% to 83% between 30°C and 160°C. This thermochromic effect is caused by hydrogen desorption upon temperature increase. The main difference between the two systems is that the face-centered-cubic to hexagonal-close- packed phase transition between YH2+δ and YH 3-δ is absent in Mg0.1Y0.9Hx, i.e., the YHx stays cubic for all 2≤x≤3. Because of this, there are no plateaus in the pressure-composition isotherms of Mg0.1Y 0.9Hx and the steepness of the optical transition upon hydrogen desorption increases drastically compared to pure YHx.
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