Organic Electroluminescent Devices Based On Small Molecule Spin-Coating

Organic electroluminescent light-emitting materials and devices have a widerange of applications in the design of display screen and irradiation white lighting innearly30years. On one hand, more and more organic electroluminescent materialswhich include small organic molecules and conjugated polymer materials with highefficiency, high mobility, high stability attract the attention of scholars. On the otherhand, the preparation of the organic electroluminescent device technology has alsomade great breakthrough. Although the vacuum vapor deposition method is mainpreparation of small organic molecules electroluminescent device, there are a seriesof problems, such as high production cost, complexity of process and difficulty oflarge area processing. In contrast, the solution-processing method can solve theseproblems, for example, spin coating method. The solution processing method ismainly used in the Preparation of a polymer electroluminescent devices.Considering the difficulty in purification of the polymer and the structural defects,the efficiency and stability of the organic electroluminescence device are fluctuant.Therefore, with the clear structure and good purification of small molecular, weapply the solution processing method to the organic electroluminescent smallmolecule system. The device of Solution processing Preparation of Small Molecularelectroluminescent light-emitting performance are far less than vacuum evaporation,there are two factors: firstly, the light-emitting materials which can be used forsolution processing of small organic molecules is very poor; secondly, limited by thedevice structure, holes transport layer is difficult to handle. In this paper, weresearch Solution-processable small organic molecules electroluminescentlight-emitting materials, optimize the processing conditions, and make high-qualityfilms of small organic molecules with spin coating method. Moreover,we alsocompare the performance of vacuum evaporation device and solution processing device, analysis the factors which play an important role in small organic moleculeselectroluminescent light-emitting.In the second chapter, in the first section, we study the choice of solvent,heat-treated film, hole modification, and film thickness to optimize the devicestructure and improve device efficiency.In the second section, we use the optimalconditions in the first section, the same structure of the vapor deposition device anda spin coating device were prepared, the light emitting performance of the twodevices are similar. Through detailed adjustments spin coating device and the devicestructure deposition devices can get consistent performance of the device. However,compared to the normal deposition device performance still lags behind, because webelieve that the lack of a device structure caused by the hole transport layer. In thethird section, through the structure of the material we have designed and synthesizedexcellent hole-transport luminescent material TPA-FSO, experiments show that, inthe evaporation device without the hole transport layer of NPB luminous efficiencyof the device and the same normal device, indicating that the hole transportproperties of this material excellent hole transport layer does not need to get a gooddevice performance. We prepared without a hole transport layer was spin coatingdevice to the same performance. In this chapter, we optimize the device structureand material structure obtained and deposited small molecule devices considerablespin coating devices.In the third chapter, we focus on spin coating of small molecule devices thereasons for the low efficiency, found that the different solubility of maternal andobject, caused a serious separation of the materials and aggregation is doped smallmolecules spin devices the main reasons for low efficiency.