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Studies of some short conjugation length polymeric light-emitting diode materials and their blends
Author
Liau, Chu Yaw
Supervisor
Gan, Leong Huat
Abstract
This thesis is mainly divided into five chapters. Chapter 1 gives an overview of light-emitting materials which in particular focuses on the PPV derivatives and their electrical-optical properties. Chapter 2 describes the synthesis of an intrinsically soluble copolymer, which has well defined substituted 2.5 p-phenylenevinylene units alternating hexanedioxy blocks. The polymer is characterized by 1H NMR, FTIR, UV-vis and fluorescence technique. Thermal properties are investigated with DSC and TGA under nitrogen atmosphere. The single-layer light-emitting diode device fabricated that has a simple ITO/polymer/A1 configuration shows typical diode behaviour. Photodegradation of the copolymer is also studied by applying high-intensity UV irradiation as well as well as low-intensity irradiation at a fixed wavelength to the polymer film.
Chapter 3 describes the synthesis of intrinsically soluble terpolymers, which are prepared by adding the third monomer, namely terephthaldehyde in different mole ratio to the previous two monomers described in Chapter 2. The photoluminescence of the terpolymers are found to be red-shifted in both the solution and film form as compared to the copolymer. The current-voltage characteristics clearly depict the diode behaviour of the ITO/terpolymer/A1 device.
Chapter 4 describes the synthesis of 1,4-bis(5'-methyl-2'-octyloxystryl)benzene and the effect of blending of this compound with the inert PMMA polymer matrix as well as with polymers synthesized in the earlier chapters. An enhancement in the PL intensity is observed in the homogenous film for the compound blended with the latter polymers.
Chapter 3 describes the synthesis of intrinsically soluble terpolymers, which are prepared by adding the third monomer, namely terephthaldehyde in different mole ratio to the previous two monomers described in Chapter 2. The photoluminescence of the terpolymers are found to be red-shifted in both the solution and film form as compared to the copolymer. The current-voltage characteristics clearly depict the diode behaviour of the ITO/terpolymer/A1 device.
Chapter 4 describes the synthesis of 1,4-bis(5'-methyl-2'-octyloxystryl)benzene and the effect of blending of this compound with the inert PMMA polymer matrix as well as with polymers synthesized in the earlier chapters. An enhancement in the PL intensity is observed in the homogenous film for the compound blended with the latter polymers.
Date Issued
2000
Call Number
QD381 Lia
Date Submitted
2000