Research On Design,Synthesis And Properties Of Novel Perylene Diimide Derivatives And Iridium-contained Polymer

Recently, organic solar cells (OSCs) have attracted much attention due to their advantageousproperties such as low cost, light weight, easy fabrication, controlled material design and large-areaflexible preparation, over the traditional Si-based solar cells. Generally speaking, the active layer ofOSCs is composed of electron donating and accepting materials, the status of electron donating andaccepting materials directly affect the efficiency of solar cells. During the past years, researches onelectron donating and accepting material have made great progress. A variety of excellent materialshave been discovered. But there are still many defects in active layer materials of OSCs such asstability, spectral response range and photoelectric properties compared with inorganic solar cells,the photoelectric conversion efficiency of OSCs is still low. Therefore, exploitation of the noveland better performance active layer materials of OSCs is still emphasis in this field. This thesiscommences on the study of perylene diimide and the iridium complexes, and several of novelactive layer materials had been synthesized. The main contents are listed as follows:1. In Chapter2, two novel of D-A-D perylene diimide derivatives:1,7-bis (N,N-bis(4-meth-oxyphenyl)aniline)perylene diimide(PDI-TPA),1,7-bis(N,N-bis(4-methoxy phenyl)aniline)-N-(3-(2-ethylhexoxy)propylamide)-N-hexyl-perylene diimide acrylate (PDA-TPA) were synthesizedand characterized by FT-IR,1H NMR and13C NMR. Besides, their photophysical, electrochemicaland thermal stability properties were studied. Results show that PDI-TPA and PDA-TPA not onlyhave good thermal stability, but also exhibit excellent solubility in common solvents. Theirabsorption bands span a wide range of the visible spectra and extend to the infrared region, whichcan greatly improve the utilization of the solar spectrum. In addition, they exhibit an ambipolarbehaviour. Hence, they have the potential to be used as electron donating and accepting materialsapplication in OSCs.2. In Chapter3, we synthesized a novel iridium complex (tppyBr)2Ir(tmd) which based onphenylpyridthiophene and introduce it to the main chain of polyfluorene, resulting in a series ofnew conjugated polymers PF-TPPyIr which contain iridium complex were designed, synthesizedand characterized by FT-IR,1H NMR and13C NMR. Besides, the photophysical and thermalstability properties of iridium complex were studied, and the effect of the content of iridium complex on photophysical, electrochemical and thermal stability properties of these polymers wereinvestigated. Results show that iridium complex and polymers both have good thermal stability.With the increase of iridium complex in main polymer chain, the iridium complex’s emission peakbecomes strong and the fluorene’s significantly becomes weakened under the thin film status. Itsuggests that efficient Forster energy transfer from the fluorene to the Ir complex had happened,which can benefit to improve exciton diffusion efficiency of OSCs.3. In Chapter4, by introducing iridium complex and perylene diimide to the main chain ofpolymer, a series of new conjugated polymers PF-PDI-TPPyIr which contain bipolar transmissionfunction groups were designed, synthesized and characterized by FT-IR,1H NMR and13C NMR.Besides, effects of the content of iridium complex and perylene diimide on photophysical,electrochemical and thermal stability properties of these polymers were investigated. Results showthat polymers have good thermal stability and the absorption bands of conjugated polymers span awide range of the visible spectra with good match to the solar spectrum. Under the thin film status,the relative emission of perylene diimide obviously quenches, suggesting that efficientintramolecular charge has transferred from fluorene to perylene diimide. With the increase ofiridium complex in main polymer chain, the iridium complex’s emission peak becomes strong andthe fluorene’s significantly becomes weakened. It suggests that efficient Forster energy hastransferred from fluorene to the iridium complex. These all benefit to improve exciton diffusionefficiency of OSCs. Furthermore, The HOMO and LUMO energy levels of PF-PDI-TPPyIr arearound-5.14eV and-3.82eV, respectively. Therefore, they have the potential to be used aselectron donating and accepting materials application in OSCs.