Fabrication Of Solution-Processed Organic Electroluminescent Devices

Since organic light-emitting diode(OLED)enjoys vast application potential in full-color display and solid-state lighting field,it has been attractingtremendous attentions of researchers.Solution-processed OLEDs can lower fabrication cost,but their luminous efficiency and operating stability are no match for that of their vaccum evaporation counterpart.This thesis mainly focuses on fabricating high performance solution-processed organic electroluminescent devices through strategies of varying compositions of device layers,depositing novel device layers,and selecting suitable emitting materials.1.Core-shell structured noble metal composite nanoparticles have been synthesized and then doped into the emissive layer of polymer light-emitting diode(PLED).The doped device obtained improved luminous efficiency.The results could give adequate evidence that metal-enhanced fluorescence effect could be realized in the emissive layer of PLED,and could provide a new strategy to obtain improved efficiency of solution-processed organic electroluminescent devices.2.Functional composite nanoparticles have been doped into solution-processed electron-transporting material,so as to fabricate the electron-transporting layer(ETL)of PLED.The device utilizing this doped ETL obtained enhanced luminance,improved current efficiency,and reduced turn-on voltage.3.A bi-layer hole-injecting layer(BHIL)has been designed and fabricated.which was composed of a molybdenum oxide film and an anionic polyelectrolyte layer.The BHIL could ensure the device with relatively high hole-injecting and hole-transporting abilities.The device based on BHIL possessed a comparable electroluminescence performance but a better shelf-stability relative to the device based on poly(3,4-ethylene-dioxythiophene):poly(styrene sulfonic acid)(PEDOT:PSS).4.Solution-processed fluorescence-type OLEDs with pure blue emission have been fabricated.The emissive layer of device was based on exciplex host-fluorescence small molecule guest structure,and could utilize radiative energy of unconverted singlet excitons.Through further optimizing concentration of guest material,improved efficiency in device was obtained.5.A sky-blue fluorescent small molecule with aggregation-induced emission effect has been utilized to fabricate the non-doped emissive layer of OLED.It possessed high aggregation-state emission,good solubility,and good film-forming ability.The solution-processed device based on this emissive material had simple structure and good performance.