Muschielok Christoph, Reiner Alexander, Röß-Ohlenroth Richard, Kalytta-Mewes Andreas, Volkmer Dirk, Wixforth Achim, Oberhofer Harald
Chair for Theoretical Chemistry, Technical University of Munich, Lichtenbergstraße 4, D-85747 Garching, Germany.
Chair for Experimental Physics I, University of Augsburg, Universitätsstraße 1, D-86159 Augsburg, Germany.
ACS Appl Mater Interfaces. 2022 Jul 27;14(29):33662-33674. doi: 10.1021/acsami.2c05127. Epub 2022 Jul 18.
With a view on adding to their use in trace gas sensing, we perform a combined experimental and theoretical study of the change of the conductivity of a metal organic framework (iron (1,2,3)-triazolate, Fe(ta)) with the uptake of chemically inert gases. To align our first-principles calculations with experimental measurements, we perform an ensemble average over different microscopic arrangements of the gas molecules in the pores of the metal-organic framework (MOF). Up to the experimentally reachable limit of gas uptake, we find a good agreement between both approaches. Thus, we can employ theory to further interpret our experimental results in terms of changes to the parameters of the Bardeen-Shockley band theory, electron-phonon coupling (in the form of the deformation potential), bulk modulus, and carrier effective mass. We find the first of these to be most strongly influenced through the gas uptake. Furthermore, we find the changes to the deformation potential to strongly depend on the individual microscopic arrangements of molecules in the pores of the MOF. This hints at a possible synthetic engineering of the material, e.g., by closing off certain pores, for a stronger, more interpretable electric response upon gas sorption.
为了增加它们在痕量气体传感中的应用，我们对金属有机框架（铁（1,2,3）-三唑化物，Fe(ta)）在吸收化学惰性气体时的电导率变化进行了实验与理论相结合的研究。为了使我们的第一性原理计算与实验测量结果相符，我们对金属有机框架（MOF）孔内气体分子的不同微观排列进行了系综平均。在实验可达到的气体吸收极限范围内，我们发现两种方法之间有很好的一致性。因此，我们可以利用理论进一步根据巴丁 - 肖克利能带理论参数、电子 - 声子耦合（以形变势的形式）、体积模量和载流子有效质量的变化来解释我们的实验结果。我们发现其中第一个参数受气体吸收的影响最大。此外，我们发现形变势的变化强烈依赖于MOF孔内分子的具体微观排列。这暗示了对该材料进行可能的合成工程设计，例如通过封闭某些孔，以在气体吸附时获得更强、更易解释的电响应。
