ノグチ　ユタカ   NOGUCHI Yutaka   野口　裕    所属   明治大学  理工学部    職種   専任教授
言語種別	英語
発行・発表の年月	2015/06
形態種別	学術雑誌
査読	査読あり
標題	Analyzing degradation effects of organic light-emitting diodes via transient optical and electrical measurements
執筆形態	共著(筆頭者以外)
掲載誌名	Journal of Applied Physics
掲載区分	国外
出版社・発行元	AIP publishing
巻・号・頁	117(21),pp.215502
国際共著	国際共著
著者・共著者	Tobias D. Schmidt, Lars Jäger, Yutaka Noguchi, Hisao Ishii, Wolfgang Brütting
概要	We present a comprehensive degradation study of an OLED structure comprising the well-known green phosphorescent emitter Ir(ppy)3. We use transient methods to analyze both electrical and optical changes during an accelerated aging protocol. Combining the results of displacement current measurements with time-resolved investigation of the excited states lifetimes of the emitter allows for a correlation of electrical (e.g., increase of the driving voltage due to trap formation) and optical (e.g., decrease of light-output) changes induced by degradation. Therewith, it is possible to identify two mechanisms resulting in the drop of the luminance: a decrease of the radiative quantum efficiency of the emitting system due to triplet-polaron-quenching at trapped charge carriers and a modified charge carrier injection and transport, as well as trap-assisted non-radiative recombination resulting in a deterioration of the charge carrier balance of the device.
DOI	http://dx.doi.org/10.1063/1.4921829