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.

Luminescent Ionic Transition‐Metal Complexes for Light‐Emitting Electrochemical Cells

“…Recently, Ho et al reported a more efficient NIR iTMCbased LEC reaching EQEs of 1.2 %, [196] that used the orangeemitting Ir-iTMC 36 ( Figure 27) as host and different fluorescent ionic NIR laser dyes as guest. Maximum EQE values (power efficiencies) of 0.8 % (5.6 mW W À1 ) and 1.2 % (7.8 mW W À1 ) were measured, respectively.…”

Lumineszierende ionische Übergangsmetallkomplexe für leuchtende elektrochemische Zellen

“…Ho et al beschrieben jüngst effizientere NIR-iTMC-LECs mit dem orange emittierenden Ir-iTMC 36 (Abbildung 27) als Wirt und verschiedenen ionischen NIRLaser-Fluoreszenzfarbstoffen als Gästen. [196] Maximale EQEWerte (und Leistungseffizienzen) von 0.8 % (5.6 mW W À1 ) und 1.2 % (7.8 mW W À1 ) wurden gemessen.…”

Frequency Selectivity in Pulse Responses of Pt/Poly(3-Hexylthiophene-2,5-Diyl)/Polyethylene Oxide + Li+/Pt Hetero-Junction

“…In addition, there have been numerous studies regarding the spatial distributions of the ions, charges, and dynamic p-n junctions in dynamic doping. [11]–[15] However, few studies have investigated responses to input frequency or timing during the dynamic doping process, and understanding such responses is imperative for simulating bio-learning processes. Comprehensive investigations are necessary to understand ion migration kinetics at the polymer/electrolyte interface under periodic electric fields.…”