New Approach Toward Fast Response Light‐Emitting Electrochemical Cells Based on Neutral Iridium Complexes via Cation Transport

Abstract

Here, a new method is presented to increase the turn‐on time and stability of light‐emitting electrochemical cells (LECs). To this end, a neutral iridium complex (5) containing a pendant Na+ ion that is generally known to have a faster mobility in the solid film than bulky anions is introduced, instead of the classic ionic transition metal complex (iTMC) with counter anion (7). Synthesis, photophysical and electrochemical studies of these complexes are reported. In the device configuration of ITO/5 or 7+PEO (polyethylene oxide) (100–110 nm)/Au, as the voltage increases, complex 5 emits red light at −3.6 V while complex 7 appears at –5.6 V, although their electrochemical and photophysical gap are similar. Furthermore, at constant voltage, –3 V, the turn‐on time of complex 5 was less than 0.5 min, which is a 60‐fold faster turn‐on time compared to the iTMC (7) with PF6−. These results are presumably due to the faster delivery of the Na+ ions to the electrode compared to PF6− ions. Also, the device lifetime of complex 5 exhibits a six‐fold increase in stability and a three‐fold shorter time to reach maximum brightness at constant bias compared to the device made with complex 7.

High-Efficiency Deep-Red Light-Emitting Electrochemical Cell Based on a Trinuclear Ruthenium(II)–Silver(I) Complex

“…To address the poor efficiency, the addition of an ionic moiety produced two contradicting behaviors in LECs based on complexes as follows. By the addition of an ionic moiety to E, the radiance and EQE of the ECH 3 + device were decreased from (0.16 mW·cm –2 , 0.62%) to (0.06 mW·cm –2 , 0.16%), as earlier observed in the literature for other iTMC devices. ,,,,− In contrast, for the case of complexation of E with Ag + , not only the turn-on time was improved from 79 to 12 s but also we observed an increase of the efficiency of their LEC device from 0.62 to 0.71%.…”

Dynamic Ir(III) Photosensors for the Major Human Drug-Metabolizing Enzyme Cytochrome P450 3A4

“…Compounds 5 – 7 and 14 – 15 exhibit electronic absorption maxima at 435 nm, 8 – 10 at 360 nm, and 11 – 13 are significantly red-shifted with a maxima at 500 nm in CH 3 OH (Table ). Electronic absorption spectra and extinction coefficients were consistent with data reported for parent complexes (Ir­(C∧N) 2 (bpy)) devoid of side chains. ,− ESI-MS data showed a peak at 1031.25 consistent with Δ,Λ- 12 . 1 H NMR analysis of ligand 3 reveals a singlet for the methylene unit attached to the bipyridyl fragment at 4.41 ppm and two triplets for the ethylene unit at 3.00 and 2.62 ppm, both with coupling constants of 6.8 Hz.…”

Ir(III)-Based Agents for Monitoring the Cytochrome P450 3A4 Active Site Occupancy

“…All data were consistent with the structures shown in Figure . Importantly, electronic absorption and emission spectra for 2 – 5 were in good agreement with data for the parent Ru­(II) or Ir­(III) complexes devoid of the R 1 side chain. − All complexes emit brightly when excited with 435 nm light (Figure S7), with 4 having the highest emission quantum yield of 0.086(9) and a lifetime of 1.6 μs, over twice as long as those of 2 and 3 (Table ).…”