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Title of Thesis

Investigation of Organic Materials for the Fabrication of Electric, Electronic and Photonic Devices

Author(s)

Muhammad Saleem

Institute/University/Department Details
Faculty of Engineering Sciences / Ghulam Ishaq Khan Institute of Engineering Sciences & Technology, Khyber Pukhtoonkhwa
Session
2010
Subject
Engineering Sciences
Number of Pages
247
Keywords (Extracted from title, table of contents and abstract of thesis)
Voltage, Devices, Semiconductors, Discharge, Investigation, Photonic, Materials, Electric, Electrodes, Fabrication, Organic

Abstract
Organic semiconductors have been the subject of intense scientific investigation for the past 50 years. Due to often weak bonding between organic molecules in the solid state, they share many of the properties of both semiconductors and insulators. Applications of these materials include chemical, physical and biological sensors, electric, electronic, and photonic devices. Low cost production of these devices is possible by using vacuum evaporation, spin coating, and drop casting technology. This work describes fabrication and characterization of organic semiconductor devices such as humidity, temperature, and light sensors, photoelectrochemical cells, electrochemical cells, solid-liquid and surface-type rectifying junctions.
Organic semiconductors have been the subject of intense scientific investigation for the past 50 years. Due to often weak bonding between organic molecules in the solid state, they share many of the properties of both semiconductors and insulators.Applications of these materials include chemical, physical and biological sensors, electric, electronic, and photonic devices. Low cost production of these devices is possible by using vacuum evaporation, spin coating, and drop casting technology. This work describes fabrication and characterization of organic semiconductor devices such as humidity, temperature, and light sensors, photoelectrochemical cells, electrochemical cells, solid-liquid and surface-type rectifying junctions.
Organic semiconductors 5,10,15,20-tetrakis(4′-isopropylphenyl) porphyrin (TIPP), Cu(II) 5,10,15,20-tetrakis(4′-isopropylphenyl) porphyrin (CuTIPP), Ni(II) 5,10,15,20-tetrakis(4′-isopropylphenyl) porphyrin (NiTIPP), and Zn(II) 5,10,15,20-tetrakis(4′-isopropylphenyl) porphyrin (ZnTIPP) are investigated as active materials in surface-type multifunctional sensors. As electrodes, 100 nm thick Ag films are deposited on 25 mm 25 mm glass substrate with 40.0 μm gap between them. Thin films of TIPP, CuTIPP, NiTIPP, and ZnTIPP of area 15 mm 15 mm, are thermally sublimed to cover the gap between surface-type silver electrodes. A change in electrical resistance and capacitance of the fabricated devices are observed with the increase of relative humidity, temperature and illumination. Hysteresis, response and recovery times are investigated over a wide range of relative humidity. Activation energies of the porphyrins are estimated in the solution. Investigation of directivity characteristics showed that the cell is sensitive in wide range of angles.
Electrochemical properties of Zn/PVA-I/C, Zn/PVA-KOH/C, Zn/PVA-KOH-I/C, and Zn/OD/C cells have been investigated. In these cells, polyvinyl alcohol (PVA)-iodine (I), orange dye (OD) aqueous solutions and polyvinyl alcohol-potassium hydroxide (KOH), polyvinyl alcohol-potassium hydroxide-iodine aqueous gels have been used as electrolytes, while zinc and carbon rods serve as electrodes.The current-voltage characteristics and open circuit voltage-time, charge voltage/current-time, and discharge voltage/current-time have been studied. Effects of concentration of OD in electrolyte have been examined on the discharge voltage–current, charge voltage/current–time and discharge voltage/current–time characteristics. The open-circuit voltages and short-circuit currents of the cells are observed as dependent on the orange dye concentration.The efficiency of the current discharge/charge is found larger at higher concentration of the dye.
Electrochemical properties of Zn/PVA-I/C, Zn/PVA-KOH/C, Zn/PVA-KOH-I/C, and Zn/OD/C cells have been investigated. In these cells, polyvinyl alcohol (PVA)-iodine (I), orange dye (OD) aqueous solutions and polyvinyl alcohol-potassium hydroxide (KOH), polyvinyl alcohol-potassium hydroxide-iodine aqueous gels have been used as electrolytes, while zinc and carbon rods serve as electrodes. The current-voltage characteristics and open circuit voltage-time, charge voltage/current-time, and discharge voltage/current-time have been studied. Effects of concentration of OD in electrolyte have been examined on the discharge voltage–current, charge voltage/current–time and discharge voltage/current–time characteristics. The open-circuit voltages and short-circuit currents of the cells are observed as dependent on the orange dye concentration. The efficiency of the current discharge/charge is found larger at higher concentration of the dye.
The solid-liquid junction characteristics of Al/OD aqueous solution/ITO and Al-CuPc/OD aqueous solution/ITO sandwich type cells are investigated. In these cells, the aluminum glass slide, copper phthalocyanine (CuPc) coated aluminum glass slide and indium tin oxide (ITO) coated glass slide electrodes are employed and as an electrolyte 0.25 wt.% solution of orange dye in distilled water is used. Dark current-voltage characteristics of the cells show rectifying behavior. The parameters, like rectification ratio, reverse saturation current, ideality factor and junction resistances are calculated. For interpretation of charge transport mechanism, dark I-V characteristics are analyzed by modified Shockley equation and space-charge limited currents approach.

Download Full Thesis
2,495 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS

 

x
67 KB
2

1

INTRODUCTION

1.2 Organic Semiconductor Devices
1.3 Outline of the Dissertation

1
193 KB
3 2 THEORY & LITERATURE REVIEW

2.1 Review of Literature
2.2 Theoretical Background

13
486 KB
4 3 EXPERIMENT AND MATERIALS

3.1 Introduction
3.2 Organic Semiconductor Materials
3.3 Device Fabrication
3.4 Experimental Setup Used for Characterization

57
353 KB
5 4 HUMIDITY, TEMPERATURE AND LIGHT SENSORS USING ORGANIC SEMICONDUCTOR PORPHYRINS

4.1 Introduction
4.2 Experimental Setup
4.3 Results and Discussion
4.4 Conclusion

79
720 KB
6 5 PHOTOELECTROCHEMICAL CELL

5.1 Introduction
5.2 Experimental Details
5.3 Results and Discussion
5.4 Conclusion

129
235 KB
7 6 ELECTROCHEMICAL CELLS

6.1 Introduction
6.2 Experimental Setup
6.3 Results and Discussion
6.4 Conclusion

152
259 KB
8 7 ELECTRICAL CHARACTERISTICS OF SOLID-LIQUID RECTIFYING JUNCTIONS

7.1 Introduction
7.2 Experimental Setup
7.3 Results and Discussion
7.4 Conclusion

180
174 KB
9 8 AG/OD-MO/AG SURFACE-TYPE DIODE FABRICATED BY DEPOSITION OF ORGANIC FILM FROM SOLUTION UNDER THE EFFECT OF AN ELECTRIC FIELD

8.1 Introduction
8.2 Experimental Details
8.3 Results and Discussion
8.4 Conclusion

196
239 KB
10 9 SUMMARY & FUTURE WORK

9.1 Summary
9.2 Future Work

216
71 KB