Structural Study of Diketopyrrolopyrrole Derivative Thin Films: Influence of Deposition Method, Substrate Surface, and Aging

Fynbo, C and Huss-Hansen, MK and Bikondoa, O and Gangadharappa, C and da Silva Filho, DA and Patil, S and Knaapila, M and Kjelstrup-Hansen, J (2023) Structural Study of Diketopyrrolopyrrole Derivative Thin Films: Influence of Deposition Method, Substrate Surface, and Aging. In: Langmuir, 39 (34). 12099 -12109.

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Abstract

We report the morphology and microstructure of n-dialkyl side-chain-substituted thiophene DPP end-capped with phenyl groups (Ph-TDPP-Ph) thin films and compare the influence of deposition method and substrate surface using thermally oxidized Si and graphene substrates as well as monolayer graphene surfaces with an underlying self-assembled octadecyltrichlorosilane monolayer, complemented by an aging study of spin-coated films over a 2 weeks aging period. A distinct difference in morphology was observed between spin-coated and vacuum-deposited thin films, which formed a fiber-like morphology and a continuous layer of terraced grains, respectively. After an initial film evolution, all combinations of deposition method and substrate type result in well-ordered thin films with almost identical crystalline phases with slight variations in crystallinity and mosaicity. These findings point toward strong intermolecular forces dominating during growth, and the templating effect observed for other oligomer films formed on graphene is consequently ineffective for this material type. Upon aging of spin-coated films, a noticeable evolution involving two different morphologies and crystalline phases were observed. After several days, the thin film evolved into a more stable crystal phase and a fiber-like morphology. Moreover, slight variation in optical spectra were elucidated on the basis on density functional theory calculations. These results demonstrate that thin-film properties of DPP derivatives can be tailored by manipulating the film formation process. © 2023 American Chemical Society.

Item Type:	Journal Article
Publication:	Langmuir
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to the American Chemical Society.
Keywords:	Chemical bonds; Crystallinity; Density functional theory; Deposition; Graphene; Monolayers; Morphology; Spinning (fibers); Substrates, A.Fibres; Crystalline phasis; Deposition methods; Deposition substrates; Diketopyrrolopyrroles; Side-chains; Spin-coated films; Structural studies; Substrate surface; Thin-films, Thin films
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	06 Nov 2023 03:36
Last Modified:	06 Nov 2023 03:36
URI:	https://eprints.iisc.ac.in/id/eprint/83076

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