| Photoelectric device based on the conjugated polymer is the trendency in thefuture, how to improve device carrier mobility has attracted much attention byresearchers.Ordered regions are largely responsible for charge transport, so formingordered structure or aggregated structure is the significant way to improve devicecarrier mobility. As a kind of soft matter, polymer has the characteristics of strongresponse under weak stimulation, so the conformation of conjugated polymer willhave a strong response under the stimulation of external field, while the change ofconformation will completely transform the photophysics and electron structure ofmaterial system. We have studied how to form ordered structure or aggregatedstructure under the external field (solvent, electric field) in this thesis, that is to saythe the influence of external field（solvent, electric field）on the conformation ofconjugated polymer.The study on the solvent field is very important; this is because the state ofpolymer solution will influence the film morphology and then the device performance.So choosing proper solvent for conjugated polymer is significant. We prepared PFO(poly(9,9-dioctylfluorene)) solution in different proportions of good solvent and poorsolvent and found the optical spectrum of PFO solution in different proportions ofmixed solvent appear differently; The proportion of β-phase，the special conformationof PFO, changed with solubility parameter of mixed solvent, so were the aggregatedstate of PFO. Specifically, when the proportion of chloroform and ethanol became2:8,the PFO chains changed into the regular crystals; therefore, the mixed solvent can change the conjugated polymer PFO from disordered state to ordered state. Inaddition, the effect of mixed solvent on the P3HT solution had the same conclutionlike PFO.The influence of solvent filed and temperature filed on the conjugated polymerhas been studied much by researchers. However there is few research on the influenceof electric fieldat home and abroad, and the effect of the electric filed with cleardirection on the polymer could not be ignored. We chose conjugated polymer withdifferent polarity, including non-polar polymer-PFO and polar polymer MEH-PPV, tostudy the effect of electric field on the conformation of the polymer, we found theelectric field changed the conformation of non-polar polymer PFO, basically, theproportion of PFO β-phase increased slightly; as for the polar polymer MEH-PPV, theaggregation decreased under the electric field, and the polymer chain oriented alongthe direction of electric field. Therefore, the polar polymer have more significantresponse under the electric field. |
