title: Phosphorescent sensitized fluorescent solid-state near-infrared light-emitting electrochemical cells.
abstract: We report phosphorescent sensitized fluorescent near-infrared (NIR) light-emitting electrochemical cells (LECs) utilizing a phosphorescent cationic transition metal complex [Ir(ppy)(2)(dasb)](+)(PF(6)(-)) (where ppy is 2-phenylpyridine and dasb is 4,5-diaza-9,9'-spirobifluorene) as the host and two fluorescent ionic NIR emitting dyes 3,3'-diethyl-2,2'-oxathiacarbocyanine iodide (DOTCI) and 3,3'-diethylthiatricarbocyanine iodide (DTTCI) as the guests. Photoluminescence measurements show that the host-guest films containing low guest concentrations effectively quench host emission due to efficient host-guest energy transfer. Electroluminescence (EL) measurements reveal that the EL spectra of the NIR LECs doped with DOTCI and DTTCI center at ca. 730 and 810 nm, respectively. Moreover, the DOTCI and DTTCI doped NIR LECs achieve peak EQE (power efficiency) up to 0.80% (5.65 mW W(-1)) and 1.24% (7.84 mW W(-1)), respectively. The device efficiencies achieved are among the highest reported for NIR LECs and thus confirm that phosphorescent sensitized fluorescence is useful for achieving efficient NIR LECs.
authors: Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan 71150, Taiwan.
authors: Chien-Cheng
authors: CC
authors: Ho
authors: Hsiao-Fan
authors: HF
authors: Chen
authors: Yu-Che
authors: YC
authors: Ho
authors: Chih-Teng
authors: CT
authors: Liao
authors: Hai-Ching
authors: HC
authors: Su
authors: Ken-Tsung
authors: KT
authors: Wong
mesh_terms: D004563:Electrochemistry; D004735:Energy Transfer; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D007259:Infrared Rays; D008163:Luminescent Measurements; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D009942:Organometallic Compounds