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Deposition of indigo thin films by Langmuir-Schaefer technique

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Griffo, Alessandra
dc.contributor.author Lim, Woojae
dc.date.accessioned 2019-02-03T16:01:00Z
dc.date.available 2019-02-03T16:01:00Z
dc.date.issued 2019-01-29
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/36333
dc.description.abstract The main purpose of this thesis is to explore an opportunity to create a conductive thin film on the substrate for organic semiconductors with non-amphiphilic molecules of indigo by Langmuir-Schaefer deposition. The hypothesis of this study was that high surface pressure of a Langmuir film of indigo leaded to an ordered Langmuir-Schaefer film. To do the experiment, Indigo powders were dissolved in a chloroform solvent and stirred at room temperature. The substrates of glass and SiO$_2$ for deposition were silanized to imitate a dielectric layer between a gate and a semiconducting film. After Langmuir-Schaefer deposition, the samples were mainly characterized by ultraviolet–visible spectroscopy (UV-Vis) and atomic force microscopy (AFM). In UV-Vis characterization, the max absorption peak of the indigo film on the glass substrate was red-shifted to 670 nm from 600 nm of indigo solution due to the hydrogen bond between indigo molecules. The max absorption peak of an indigo film was red-shifted as decreasing surface pressure of Langmuir film and/or the number of deposition cycles. The AFM characterization revealed that the thickness of indigo thin film was around 5nm. It was also found that aggregates of indigo covered the surfaces of the samples and calculated root-mean-square surface roughness lay in between 2.6 to 18 nm. In sum, this study showed that Langmuir-Schaefer deposition succeeded in creating an indigo thin film, and low surface pressure of a Langmuir film consisting of non-amphiphilic molecules of indigo has a positive impact to have an ordered Langmuir-Schaefer film. en
dc.format.extent 55
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.title Deposition of indigo thin films by Langmuir-Schaefer technique en
dc.type G2 Pro gradu, diplomityö fi
dc.contributor.school Kemian tekniikan korkeakoulu fi
dc.subject.keyword indigo dye en
dc.subject.keyword Langmuir deposition en
dc.subject.keyword organic semiconductor en
dc.subject.keyword surface pressure-area isotherm en
dc.subject.keyword Langmuir film en
dc.identifier.urn URN:NBN:fi:aalto-201902031502
dc.programme.major Functional materials fi
dc.programme.mcode CHEM3025 fi
dc.type.ontasot Master's thesis en
dc.type.ontasot Diplomityö fi
dc.contributor.supervisor Laaksonen, Päivi
dc.programme Master's Programme in Chemical, Biochemical and Materials Engineering fi
dc.location PK fi
local.aalto.electroniconly yes
local.aalto.openaccess yes

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