Geri Dön

Solution processable semiconductor thin films: Correlation between morphological, structural, optical and charge transport properties

Başlık çevirisi mevcut değil.

PDF İndir

  1. Tez No: 403075
  2. Yazar: DİLEK IŞIK
  3. Danışmanlar: PROF. CLARA SANTATO, PROF. SYLVAIN TURENNE
  4. Tez Türü: Doktora
  5. Konular: Metalurji Mühendisliği, Metallurgical Engineering
  6. Anahtar Kelimeler: Belirtilmemiş.
  7. Yıl: 2013
  8. Dil: İngilizce
  9. Üniversite: Université de Montréal (Ecole Polytechnique de Montréal)
  10. Enstitü: Yurtdışı Enstitü
  11. Ana Bilim Dalı: Belirtilmemiş.
  12. Bilim Dalı: Belirtilmemiş.
  13. Sayfa Sayısı: 154

Özet

Özet yok.

Özet (Çeviri)

This Ph.D. thesis is a result of multidisciplinary research bringing together fundamental concepts in thin film engineering, materials science, materials processing and characterization, electrochemistry, microfabrication, and device physics. Experiments were conducted by tackling scientific problems in the field of thin films and interfaces, with the aim to correlate the morphology, crystalline structure, electronic structure of thin films with the functional properties of the films and the performances of electronic devices based thereon. Furthermore, novel strategies based on interfacial phenomena at electrolyte/thin film interfaces were explored and exploited to control the electrical conductivity of the thin films. Three main chemical systems were the object of the studies performed during this Ph.D., two types of organic semiconductors (azomethine-based oligomers and polymers and soluble pentacene derivatives) and one metal oxide semiconductor (tungsten trioxide, WO3). To explore the morphological properties of the thin films, atomic force microscopy was employed. The morphological properties were further investigated by hyperspectral fluorescence microscopy and tentatively correlated to the charge transport properties of the films. X-ray diffraction (Grazing incidence XRD, GIXRD) was used to investigate the crystallinity of the film and the effect of the heat treatment on such crystallinity, as well as to understand the molecular arrangement of the organic molecules in the thin film. The charge transport properties of the films were evaluated in thin film transistor configuration. For electrolyte gated thin film transistors, time dependent transient measurements were conducted, in parallel to more conventional transistor characterizations, to explore the specific effects played on the gating by the anion and cation constituting the electrolyte. The capacitances of the electrical double layers at the electrolyte/WO3 interface were obtained from electrochemical impedance spectroscopy. In the context of ARTICLE 1, thin film transistors based on soluble pentacene derivatives (prepared by the research group directed by Professor J. Anthony, at the University of Kentucky) were fabricated and characterized. GIXRD results performed on the thin films suggested a molecular arrangement favorable to charge transport in the source-drain direction, with the π-π stacking direction perpendicular to the channel. In ARTICLE 1, HMDS-treated SiO2 substrates were used, to improve the surface coverage and to limit charge trapping at the dielectric surface. AFM showed good film coverage. The transistors showed ambipolar characteristics, attributed to the good matching between Au electrode work function and highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the pentacene derivative. The work reported in ARTICLE 2 deals with π-conjugated thiopheno-azomethines (both in oligomer and polymer form) and oligothiophene analogues. In the former case, couplings in the polymer are based on azomethine (-N=C-) moieties whereas in the latter case they are based on more conventional protocols (-C=C-). The effect of the coupling protocols on the corresponding thin film transistors behavior was studied. The key conclusion of this study was that thiopheno-azomethines thin films can be effectively incorporated into organic transistors: thin films of oligothiopheno-azomethines and the oligothiophenes exhibit p-type behavior whereas thin films of polythiopheno-azomethine exhibit an ambipolar behavior. The hole mobility of the heat-treated thin films of oligothiopheno-azomethines was three orders of magnitude higher compared to its oligothiophene analogue. AFM, coupled with hyperspectral fluorescence imaging, were used to investigate the micro- and nano-scale surface coverage. For the oligothiopheno-azomethine we were able to quantitavely deduce the surface coverage. To contribute to the exploration of innovative strategies for low power consuming solution based electronics and capitalizing on the expertise of the group in the synthesis of solution deposited WO3 films the electrolyte gating approach was explored in ARTICLE 3. Ionic liquids, that are molten salts at room temperature, were employed as the electrolyte. Ionic liquids are attractive for their low volatility, non-flammability, ionic conductivity and thermal and electrochemical stability. Thin films of WO3 were deposited onto pre-patterned ITO substrates (source-drain interelectrode distance, 1 mm) prepared by wet chemical etching. SEM and AFM showed an interconnected film nanostructure. Electrolyte gated WO3 thin film transistors making use of 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TFSI]), 1-butyl-3-methyl imidazolium hexafluoro phosphate ([BMIM][PF6]), and 1-ethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) showed an n-type transistor behavior. The possibility to obtain WO3 electrolyte gated transistors represents an opportunity to fabricate electronic devices working at relatively low operating voltages (about 1 V) by using simple fabrication techniques.

Benzer Tezler

  1. Tez No

    450496

    Design, synthesis, and characterization of n-type and ambipolar small molecules as air-stable and solution-processable semiconductors in ofets

    Ofet'ler için havada kararlı ve çözücüde işlenebilen n-tipi ve ambipolar küçük moleküllerin dizaynı, sentezi ve karakterizasyonu

    RESUL ÖZDEMİR

    Yüksek Lisans

    İngilizce

    İngilizce

    2016

    KimyaAbdullah Gül Üniversitesi

    Malzeme Bilimi ve Nanoteknoloji Ana Bilim Dalı

    DOÇ. DR. HAKAN USTA

  2. Tez No

    513753

    Solution-processable rodshaped molecular semiconductors and fieldeffect transistor applications

    Solüsyondan proses edilebilir çubuk yapısında moleküler yarı iletkenler ve alan etkili transistör uygulamaları

    İBRAHİM DENEME

    Yüksek Lisans

    İngilizce

    İngilizce

    2018

    KimyaAbdullah Gül Üniversitesi

    Nanoteknoloji ve İleri Malzemeler Ana Bilim Dalı

    DOÇ. DR. HAKAN USTA

  3. Tez No

    731763

    Novel semiconducting materials for high-performance organic transistors and solar cells

    Yüksek performanslı organik transistörler ve güneş pilleri uygulamaları için yeni yarı iletken malzemeler

    AYŞE CAN

    Doktora

    İngilizce

    İngilizce

    2022

    KimyaAbdullah Gül Üniversitesi

    Malzeme Bilimi ve Makine Mühendisliği Ana Bilim Dalı

    PROF. DR. HAKAN USTA

  4. Tez No

    540995

    Design, synthesis, and characterization of functional organic materials for optoelectronic applications

    Optoelektronik uygulamalar için fonksiyonel organik malzemelerin dizaynı, sentezi ve karakterizasyonu

    MEHMET ÖZDEMİR

    Doktora

    İngilizce

    İngilizce

    2018

    KimyaAbdullah Gül Üniversitesi

    Malzeme Bilimi ve Makine Mühendisliği Ana Bilim Dalı

    DOÇ. DR. HAKAN USTA

  5. Tez No

    574047

    Optical gain and lasing of colloidal semiconductor quantum wells intimately integrated into optical cavities

    Optik çınlaçlar içinde yakinen tümleştirilmiş koloidal yarıiletken kuantum kuyularının optik kazancı ve lazer eylemi

    MUSTAFA SAK

    Yüksek Lisans

    İngilizce

    İngilizce

    2019

    Elektrik ve Elektronik Mühendisliğiİhsan Doğramacı Bilkent Üniversitesi

    Elektrik-Elektronik Mühendisliği Ana Bilim Dalı

    PROF. DR. HİLMİ VOLKAN DEMİR

Geri Dön