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Disorder and localization dynamics in polymorphs of the molecular semiconductor pentacene probed by in situ micro-Raman spectroscopy and molecular dynamics simulations

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Ando, M 
Yoneya, M 
Kehoe, TB 
Ishii, H 
Minakata, T 


© 2019 American Physical Society. ©2019 American Physical Society. To reveal the relationship between microstructural disorder and charge localization dynamics in a van-der-Waals-bonded molecular semiconductor, the electrical properties of field-effect transistors with zone-cast pentacene films were characterized by using in situ micro-Raman spectroscopy to monitor the films' intermolecular and intramolecular vibrations. Transformations from a high-temperature phase with reduced molecular vibration along the long axis that were induced by electron localization in pentacene molecules at the channel interface and transformations from a low-temperature phase with increased molecular vibration that were induced by the electron delocalization were clearly observed under gate-bias stress, photoexcitation, and thermal annealing. Multilayer molecular dynamics simulations revealed that electrons should be localized in each pentacene molecule to stabilize the low-temperature phase and that the intramolecular Raman peak corresponds to the amount of out-of-plane molecular displacement that is most influential to charge localization and mobility reduction induced by fluctuating transfer integrals. We propose a unified picture to describe the relationship between out-of-plane structural disorder and charge localization dynamics in pentacene polymorphs.



3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, 3407 Theoretical and Computational Chemistry, 40 Engineering, 51 Physical Sciences, 4016 Materials Engineering, 5104 Condensed Matter Physics

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Physical Review Materials

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American Physical Society (APS)


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