Title
Electronic properties of interfaces between domains in organic semiconductors
Creator
Mladenović, Marko, 1988-
Copyright date
2016
Object Links
Select license
Autorstvo-Nekomercijalno 3.0 Srbija (CC BY-NC 3.0)
License description
Dozvoljavate umnožavanje, distribuciju i javno saopštavanje dela, i prerade, ako se navede ime autora na način odredjen od strane autora ili davaoca licence. Ova licenca ne dozvoljava komercijalnu upotrebu dela. Osnovni opis Licence: http://creativecommons.org/licenses/by-nc/3.0/rs/deed.sr_LATN Sadržaj ugovora u celini: http://creativecommons.org/licenses/by-nc/3.0/rs/legalcode.sr-Latn
Language
English
Cobiss-ID
Committee report
Theses Type
Doktorska disertacija
description
Datum odbrane: 19. 01. 2017.
Other responsibilities
mentor
Radovanović, Jelena, 1973-
član komisije
Vukmirović, Nenad
član komisije
Milanović, Vitomir, 1947-
član komisije
Balaž, Antun, 1973-
član komisije
Matavulj, Petar, 1971-
University
Univerzitet u Beogradu
Faculty
Elektrotehnički fakultet
Alternative title
Elektronska svojstva organskih poluprovodnika na granicama domena
Publisher
[M. Mladenović]
Format
127 listova
description
Electrical and Computer Engeneering - Nanoelectronics and Photonics / Elektrotehnika i računarstvo - Nanoelektronika i fotonika
Abstract (en)
The aim of this thesis is to provide a link between atomic and electronic structure
of different types of interfaces between domains in organic semiconductors.
In polycrystalline small-molecule organic semiconductors interfaces are formed between
single crystalline domains. We found that grain boundaries in polycrystalline
naphthalene introduce trap states within the band gap of the material. Trap states
are localized on closely spaced pairs of molecules from opposite sides of the boundary.
Realistic conjugated polymers, such as poly(3-hexylthiophene) (P3HT), contain
mixed crystalline and amorphous domains. We found that HOMO state of the interface
between crystalline and amorphous domain in P3HT belongs to crystalline
domains. States that belong to both domains and trap states were not found. Effects
of thermal disorder are important in realistic conjugated polymers. Our results
show that disorder in backbone chains of P3HT has strong effect on the electronic
structure and leads to the localization of the wave functions of the highest states
in the valence band, similar to the ones that occur in amorphous polymers. At the
interfaces between two materials in organic electronic devices, effects of spontaneous
polarization in one or both of them on electronic properties can be pronounced. We
show that ordered P3HT exhibits spontaneous polarization along the backbone direction,
which is caused by the lack of inversion symmetry due to head-to-tail side
chains arrangement. We additionally show that spontaneous polarization in ordered
P3HT keeps significant values even at room temperature when the effects of thermal
disorder are important.
Abstract (sr)
Cilj ove disertacije da je pruži vezu izmedu atomske i elektronske strukture
različitih tipova granica izmedu domena u organskim poluprovodnicima. U polikristalnim organskim poluprovodnicima na bazi malih molekula granica se formira između homogenih kristalnih domena. Ustanovili smo da granica u polikristalnom naftalinu dovodi do pojave stanja zamki u energijskom procepu materijala, lokalizovanih na parovima molekula sa različitih strana granice izmedu kojih je rastojanje malo...
Authors Key words
organic semiconductors, electronic structure, domain interface, thermal
disorder, crystalline domain, amorphous domain, spontaneous polarization
Authors Key words
organski poluprovodnici, elektronska struktura, granica domena,
termalna neuredenost, kristalni domen, amorfni domen, spontana polarizacija
Classification
621.3
Type
Tekst
Abstract (en)
The aim of this thesis is to provide a link between atomic and electronic structure
of different types of interfaces between domains in organic semiconductors.
In polycrystalline small-molecule organic semiconductors interfaces are formed between
single crystalline domains. We found that grain boundaries in polycrystalline
naphthalene introduce trap states within the band gap of the material. Trap states
are localized on closely spaced pairs of molecules from opposite sides of the boundary.
Realistic conjugated polymers, such as poly(3-hexylthiophene) (P3HT), contain
mixed crystalline and amorphous domains. We found that HOMO state of the interface
between crystalline and amorphous domain in P3HT belongs to crystalline
domains. States that belong to both domains and trap states were not found. Effects
of thermal disorder are important in realistic conjugated polymers. Our results
show that disorder in backbone chains of P3HT has strong effect on the electronic
structure and leads to the localization of the wave functions of the highest states
in the valence band, similar to the ones that occur in amorphous polymers. At the
interfaces between two materials in organic electronic devices, effects of spontaneous
polarization in one or both of them on electronic properties can be pronounced. We
show that ordered P3HT exhibits spontaneous polarization along the backbone direction,
which is caused by the lack of inversion symmetry due to head-to-tail side
chains arrangement. We additionally show that spontaneous polarization in ordered
P3HT keeps significant values even at room temperature when the effects of thermal
disorder are important.
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