Kang, Nam Su Ju, Byeong-Kwon Kim, Ji Whan Kim, Jang-Joo Yu, Jae-Woong Chin, Byung Doo 2024-01-20T23:02:17Z 2024-01-20T23:02:17Z 2021-09-03 2008-07-15 0021-8979 https://pubs.kist.re.kr/handle/201004/133322 We have investigated the effects of interfacial layers on the properties of soluble phosphorescent organic light emitting devices. Two kinds of polyfluorene-based interfacial layer materials have been studied; both were spin coated on top of PEDOT:PSS to form the insoluble layers by thermal annealing. The molecular-doped, phosphorescent light emitting layer comprising a polymeric host, small molecular host, and guest molecule was fabricated onto the thin interfacial layer. The photoluminescence quantum yield (PLQY) of these layers was measured with an integrating sphere. We have calculated the PLQY values of the single phosphorescent light emitting layer and various organic multilayers incorporating the interfacial layers, showing that a reduction in PLQY due to the interfacial quenching is more significant in the thicker interfacial layer structures. In spite of the decrease in PLQY induced by the triplet energy mismatch, polyfluorene-based interfacial layers improved the charge injection from PEDOT: PSS to the emitting layer, which results in the enhanced brightness and current. The triplet quenching by the interfacial layer could explain the reduction in luminous efficiency of the devices compared to the reference. This was also investigated by studying the charge carrier trapping, change in the spectral characteristics induced by the shift in the emission zone, and the analysis on the carrier balance of devices. (c) 2008 American Institute of Physics. English AMER INST PHYSICS IRIDIUM PHOSPHORESCENCE TRANSPORT COMPLEX ENERGY SYSTEM DIODES FILMS Correlation of photoluminescent quantum efficiency and device characteristics for the soluble electrophosphorescent light emitter with interfacial layers Article 10.1063/1.2959817 1 JOURNAL OF APPLIED PHYSICS, v.104, no.2 JOURNAL OF APPLIED PHYSICS 104 2 scie scopus 000258174800125 2-s2.0-48849102202 Physics, Applied Physics Article IRIDIUM PHOSPHORESCENCE TRANSPORT COMPLEX ENERGY SYSTEM DIODES FILMS Interface Electrophosphorescence