Institute of Solid State Physics
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SS22 WS22 SS23 WS23 SS24 WS24 Guidelines for Master Students
Modelling anharmonic properties and thermal conductivity in organic semiconductors Thermal transport is important for most practical applications of functional materials. In (opto-) electronic devices, it is typically desirable that materials dissipate heat as efficiently as possible. Conversely, for special purposes, like thermoelectric energy conversion, a low thermal conductivity is crucial. Organic semiconductors (OSC) are particularly relevant for optoelectronic applications, which is exemplified by their commercially successful use in displays for many devices. Moreover, OSCs have also been explored as promising candidates for thermoelectric applications. A central aspect for understanding thermal transport in OSCs is to realize, how the thermal conductivity and the structure of an OSC material are interrelated. In this work the method of non-equilibrium molecular dynamics (NEMD) is used to simulate the thermal conductivity for a range of different acene-based OSC materials. In order to achieve proper results, a well-established and defined force field is crucial, which should not only represent the harmonic phonon features but also the anharmonic properties of the potential. The latter can be tested by simulating the thermal expansion of the materials and comparing them, where possible, to experimental data. During the last year, we have gained considerable experience using and parametrizing the second generation, system-specific force field MOF-FF. Therefore, in my studies analogous force fields have been tested. |
