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Solutal‐Marangoni‐Flow‐Mediated Growth of Patterned Highly Crystalline Organic Semiconductor Thin Film Via Gap‐Controlled Bar Coating
Author(s) -
Lee Seon Baek,
Lee Siyoung,
Kim Dae Gun,
Kim Seung Hyun,
Kang Boseok,
Cho Kilwon
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202100196
Subject(s) - materials science , marangoni effect , bar (unit) , coating , organic semiconductor , thin film , organic electronics , semiconductor , nucleation , flexible electronics , thin film transistor , printed electronics , nanotechnology , optoelectronics , solution process , roll to roll processing , composite material , layer (electronics) , transistor , inkwell , chemistry , physics , organic chemistry , quantum mechanics , voltage , meteorology , surface tension
Application‐oriented patterned growth of organic semiconductor (OSC) thin films with single crystalline domains is crucial for fabricating sophisticated high‐performance organic‐electronic and optoelectronic devices; however, fabricating these patterned nanometer‐thick crystals in a simple, fast, and effective manner is a difficult task with a roll‐to‐roll printing process. Here, a simple bar‐coating approach to form an array of single‐crystal‐like OSC thin‐film patterns at a rate of a few millimeters per second is introduced. To this end, the processing parameters of a gap‐controlled bar‐coating method is optimized, including coating speed, crystal nucleation, and solution fluidics, which allow a high degree of morphological control of bar‐coated OSC films in an area of several centimeters. In particular, it is demonstrated that the solutal‐Marangoni flow induced by a suitable solvent additive can considerably improve molecular mass transport and induce favorable vertical phase separation. Thus, organic transistors based on the OSC patterns fabricated with the additive‐assisted bar coating show a field‐effect mobility of up to 20 cm 2 V −1 s −1 and superior operational stability. The proposed bar coating method will facilitate an industry‐level application of organic electronics.