All Solution-Processed Quintuple-Layer Organic Light-Emitting Diodes Containing Organic-Inorganic Hybrid Active Layers Fabricated by Sol-Gel Method

Abstract

Organic-inorganic hybrid thin films were fabricated using the sol-gel method and applied to multi-layer organic light-emitting diodes (OLEDs) as an active layer. A polymer emissive material poly (9,9-dioctyl-fluorene-co-N-4-butylphenyl-diphenylamine) (TFB) was solved in a sol-gel reaction accelerator perhydropolysilazane (PHPS). The PHPS solution turned into SiO2 by humidity treatment. Thus, the TFB:PHPS solution became SiO2 thin films in which the organic emissive material TFB was dispersed. All the organic layers of OLEDs can be fabricated using solution-process because the organic-inorganic hybrid active layer is not soluble with the adjacent organic layers. Consequently, we successfully fabricated quintuple-layer OLEDs consisting of the following five organic films: hole-injection, hole-transporting, active (organic-inorganic hybrid) electron-transporting, and electron-injection layers. Electroluminescence (EL) was successfully observed.