Issue 43, 2019

The effect of side-chain length on the microstructure and processing window of zone-cast naphthalene-based bispentalenes

Abstract

The solubilizing side-groups of solution-processable π-conjugated organic semiconductors affect both the crystal structure and microstructure of the respective thin films and thus charge-carrier mobility in devices. In this work, we explore how the alkyl side-chain length influences thin-film structure and charge transport in field-effect transistors of zone-cast, naphthalene-based bispentalenes. By tuning the alkyl-chain length and the casting speed, we alter the microstructure from highly aligned ribbons, to feathered ribbons, to disordered grains. Concurrently, the hole mobility changes over two orders of magnitude, from 0.001 cm2 V−1 s−1 at the fastest speeds to roughly 0.1 cm2 V−1 s−1 at slower speeds. The highest mobilities correspond to the presence of an aligned ribbon morphology. While optical measurements indicate negligible electronic differences between the molecules, grazing incidence X-ray diffraction measurements show that the films display different degrees of order and alignment. The compound with pentyl side-chains exhibits the largest tolerance to different processing conditions, yielding an aligned ribbon microstructure and high mobility over a wide range of casting speeds. Our results highlight the impact that even small changes to the molecular structure can have on the processing window and transport properties of thin-film devices.

Graphical abstract: The effect of side-chain length on the microstructure and processing window of zone-cast naphthalene-based bispentalenes

Supplementary files

Article information

Article type
Paper
Submitted
12 अगस्त 2019
Accepted
10 अक्तूबर 2019
First published
11 अक्तूबर 2019

J. Mater. Chem. C, 2019,7, 13493-13501

The effect of side-chain length on the microstructure and processing window of zone-cast naphthalene-based bispentalenes

K. P. Goetz, K. Sekine, F. Paulus, Y. Zhong, D. Roth, D. Becker-Koch, Y. J. Hofstetter, E. Michel, L. Reichert, F. Rominger, M. Rudolph, S. Huettner, Y. Vaynzof, E. M. Herzig, A. S. K. Hashmi and J. Zaumseil, J. Mater. Chem. C, 2019, 7, 13493 DOI: 10.1039/C9TC04470A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements