We propose the use of a frequency-dependent photothermal measurement as a complement to light-flash, i.e., time-dependent, measurements to determine the through-plane thermal diffusivity of small, thin samples, e.g., semiconducting polymers and small organic molecule crystals. The analysis is extended from its previous use with some opaque conducting polymers to materials with finite absorption coefficients, such as crystals of 6,13-bis(triisopropylsilylethynyl)pentacene. Taking into account the finite absorption coefficients of the latter gives a value of diffusivity, D ≈ 0.10 mm2/s, much smaller than previously estimated and more consistent with its expected value. We also briefly discuss the effects of coating samples for the measurement to improve their optical properties.
|Journal||Journal of Applied Physics|
|State||Published - Oct 21 2018|
Bibliographical noteFunding Information:
We thank Z. Li, J. Edberg, F. Zhang, and X. Crispin (Linkoping U.) for providing samples of NFC-PEDOT and PEDOT:PSS, M. M. Payne and J. E. Anthony (U. Kentucky) for both providing samples of TIPS-pentacene and helpful suggestions in preparing new crystals, and Y. Yao and M. Weisenberger (U. Kentucky) for helpful discussions on techniques. This research was supported by the National Science Foundation (NSF) (Grant No. DMR-1262261).
© 2018 Author(s).
ASJC Scopus subject areas
- Physics and Astronomy (all)