Slot-die Coating Based Organic Wide-band Gap Polymer Film And Light Emitting Diode Device

Organic polymer light-emitting diodes(PLEDs)attracts widespread attention for the characteristics it has: solution-processability,compatible with flexible processes,low-cost fabrication approach,full-spectrum color display,and high-brightness light emission driven by low voltage.However,there are limitations in traditional solution process of fabricating polymer thin-films,such as low fabrication efficiency of the thin-films,small available area,and low solution utilization rate.Introducing the printing process can realize the continuous and controllable fabrication of flexible large-area thin-films devices.Therefore,printing display is one of the significant developments orienations of the new-type display industry in the future development.Although polymer printing display has already acheived some remarkable advances,the large-area solution processing and device applications of thin-films have not yet met the expected results.Thus,there still exists numerous key issues to be solved urgently,such as,stability of thin-films,the variable condensed state of thin-film in large-area processing,and device repeatability.This thesis takes wide-bandgap blue-light polyfluorenes as the research object,and explores the problems encountered in large-area processing of polymer thin-films through the slot-die coating process.Based on the slot-die coating process,we conducted researches on various thin-films aggregations in the polyfluorene system,and the processing parameters of the large-area processing.The research provides a method for processing the polyfluorene semiconductor thin-films in different phases,which can realize the large-area processing under low temperature conditions,and successfully achieves the preparation of large-area flexible polymer LED devices,and provides new research ideas for the commercialization of organic printing displays.1.While exploring the relationship between the film phase and the processing technology of the polymer thin-films,we found that the polyfluorene semiconductor thin-films can induce various phases by processing the multiple layers through the slot-die coating process.By slot coating process,the PEDOT: PSS film was used to induce the PEDOT:PSS film to transform into ? phase at 80 ?.So far,the known methods for regulating the phase of polyfluorene semiconductor thin-films are difficult to realize in large-area processing.This research provides a new solution for the controllable condensed state of polyfluorene materials in large-area processing.2.Comparing fabrications of PHDPF-Cz thin-film at low temperature and low speed(20 ? / 40 Hz)with that in optimal conditions(80 ? / 80 Hz),we found that modulating processing parameters of apparatus could optimize the quality of thin-film,and effectively inhibit coffee ring effect in the solution process on the film formation,and finally successfully fabricate a flexible large-area polyfluorene blue LED with a device structure of PET / ITO / PEDOT: PSS /PHDPF-Cz/ TPBi / Li F / Al under air conditions.3.Based on the slot-die coating process to fabricate large-area polygrid thin-films,we discuss the photooxidation stability of the large-area processed polygrid thin-film under UV lamp irradiation for 2,4,6,8,and 10 hours respectively,compare it with other four polyfluorene materials(PFO,PHDPFCz,PODPF,PGC2F),and lay a sound foundation for the realization of large-area display devices based on nanopolymers.