The Design And Synthesis For Conjugated Macro-electroytes And Corresponding Applications In Organic Opto-electronic Devices

To develop high efficient,stable,cost-effective,solution processed electron transport/inject/selective materials are key factors to further improve the progress of organic optoelectronic devices.In this study,combined with the advantages of multi-armed conjugated macromolecules,such as well-defined chemical structure,high purity,excellent film-forming ability,a serious of high efficienct electron transport/inject/selective interfacial materials were developed.In addition,the motivation on the polymer backbone was also considered.Based on these materials,the relationship between chemical structure and electron transport ability,the selectivity on polar pendents and corrsonding effect,the application on various device structures,as well as the mechanism on interfacial modification were systematically investigated.Specfically,the dissertation was divided into six chapters.In Chapter 1,the basic principles of polymer light-emitting diodes(PLEDs)and polymer organic solar cells(PSCs)were introduced briefly.In addition,the developement on electron selective interlayer was discussed in detail,especially on those organic based interlayer,such as conjugated polyelectrolytes andnon-conjugated polyelectrolytes.Meanwhile,the advantages of multi-armed conjugated macromolecules and their developments in the past few years were introduced as well.At the last part of this chapter,the research motivations and main studies of this dissertation were put forward thereupon.In Chapter 2,a hydrophilic polyfluorene-based conjugated polymer,PPFN-OH has been synthesized and utilized as cathode interlayer for both polymer light emitting diodes(PLEDs)and solar cells.For comparison,another CPE namely(PFN-OH)has also been investigated.They comprise the same polyfluorene backbone structures with,respectively,diethanolaminohexyl(PFNOH)and diethanolaminohexoxyphenyl(PPFN-OH)substituents attached to the C9 carbon of the fluorene repeat unit.The results of device performance confirmed that PPFN-OH showed better electrical stability,thus to be a promising interlayer material for high performance solution processed organic optoelectronic devices.In Chapter 3,We present the design and synthesis of a hydrophilic mono-disperse conjugated starburst macromolecule,TrOH,grafted with diethanolamine groups on its side chains,as efficient electron transport/injection layer for solution-processed organic light emitting diodes(OLEDs),For comparison,devices with Ca/Al cathodes and a conjugated polymer grafted with the same polar pendant groups(PFN-OH)have also been fabricated.Further research demonstrated that the superior performance of TrOH origins from its appropriate surface roughness and more uniform morphology.In Chapter 4,both TrOH and another star-shaped mono-disperse conjugated macroelectrolyte grafted with cationic side chains,TrNBr,composed of identical conjugated backbone,were designed,synthesized,and utilized as efficient electron-collecting cathode interlayers for inverted polymer solar cells.The effect on bottom electrode work function,surface morphology after interlayer deposition,as well as their thickness dependent performance was deeply investigated.In contrast to regular Ca/Al based on devices,and inverted solar cells based on sol gel ZnO,the devices based on the interfacial materials discussed in this chapter both showed high efficiency.In Chapter 5,light soaking effects in inverted organic solar cells functionalized with conjugated macroelectrolyte electron-collecting interlayers was studied systematically.In Chapter 6,the conclusion and prospect have been summarized.