유기 발광 소자에서 정공 주입 버퍼층의 효과

Abstract

Current-voltage-luminance characteristics of organic light-emitting diodes (OLEDs) were measured in the temperature range of 10 K ～ 300 K. Indium-tin-oxide (ITO) was used as an anode and aluminum as a cathode in the device. Organic of N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD) was used for a hole transporting material, and tris (8-hydroxyquinolinato) aluminum (Alq3) for an electron transporting material and emissive material. And copper phthalocyanine (CuPc), poly(3,4-ethylenedi oxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and poly(N-vinylcarbazole) (PVK) were used for hole-injection buffer layers. From the analysis of electroluminescence (EL) and photoluminescence (PL) spectra of the Alq3, the EL spectrum is more greenish then that of PL. And the temperature-dependent current-voltage characteristics were analyzed in the double and multilayer structure of OLEDs. Electrical conduction mechanism was explained in the region of high-electric and low-electric field. Temperature-dependent luminous efficiency and operating voltage were analyzed from the current-voltage- luminance characteristics of the OLEDs.