Screening structure–property correlations and device performance of Ir(iii) complexes in multi-layer PhOLEDs

Abstract

The structure-property correlations of a set of heteroleptic red- and green-emitting Ir(III) complexes with different temperature sensitivities and charge trapping capabilities are described, revealing superb performance in multi-layer phosphorescent organic light-emitting diodes (PhOLEDs) expressed by very high maximum luminous efficiencies up to 36.8 cd A(-1). Using 2-phenylpyridine and with 2-(naphthalen-1-yl)pyridine as the C^N ligand, the resulting red emitting complex featured a maximum luminous efficiency of 10.8 cd A(-1); one of the most excellent device performances within this class of red Ir(III) emitters.

Improving the balance of carrier mobilities of host–guest solid-state light-emitting electrochemical cells

“…The research results of this work confirm that in addition to reducing self-quenching of guest molecules as revealed in previous reports, 14,26,52 the strategy of utilizing a carrier transporting host doped with a proper carrier trapping guest would also improve balance of carrier mobilities of the emissive layer and thus would be effective in optimizing device efficiencies of LECs. These device efficiencies obtained in hostguest LECs are comparable with those reported in polymer LEDs [61][62][63][64][65][66][67][68][69] and multi-layered OLEDs [70][71][72][73] doped with iridium(III) emitters.…”

Blue-to-Green Emitting Neutral Ir(III) Complexes Bearing Pentafluorosulfanyl Groups: A Combined Experimental and Theoretical Study

“…Time-resolved emission (in MeCN): λ exc 378 nm. Solution Φ PL values were measured using quinine sulfate as the external reference (λ em 450 nm in MeCN, Φ r = 54.6% in 0.5 M H 2 SO 4 as found in ref (50); the error in prediction of λ em of complexes 1 – 4 were calculated using the equation error = |[λ em (298 K) – E AE ]/λ em (298 K)| in eV × 100%, where E AE = adiabatic emission energy).cFrom ref (27) in MeCN (broad and structureless emission profile).dFrom ref (27) in 2-MeTHF.eFrom ref (51) in CHCl 3 (broad and structureless emission profile).fFrom ref (21) in DCM (structured emission profile).gValues of vibronic bands were estimated by visual inspection of the corresponding spectra.hFrom ref (28) in toluene (structured emission profile).iFrom ref (38) in DCM (structured emission profile).jFrom ref (46) in DCM.kFrom ref (42) in 2-MeTHF (broad and structureless emission profile for R7 and only emission maximum value is reported for R10 ).lFrom ref (22) in MeCN (structured emission profile for R8 , broad and structureless emission profile for R9 ).…”

Bimetallic Cyclometalated Iridium(III) Diastereomers with Non‐Innocent Bridging Ligands for High‐Efficiency Phosphorescent OLEDs

“…[1b, 3-5] Cyclometalated iridium(III) complexes are widely exploited because of their excited-state lifetimes on the microsecond time scale, high quantum yields, good thermal and chemical stability, and tunability of the emission color. [6][7][8][9][10] In this context, the prototype complex is fac-[Ir(ppy) 3 ] (ppy = 2-phenylpyridine).The photoluminescence quantum yields of dinuclear metal complexes [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] are usually considerably lower than those of their mononuclear analogues [12,14,23,24] (although there are exceptions), [25] leading to the established view that dinuclear complexes give poor device performance. [26,27] For example, the quantum yield of the bis(m-Cl) bridged dimer [{Ir(ppy) 2 Cl} 2 ] (1) is only 0.5 %, [11] whereas that of fac-[Ir(ppy) 3 ] is 40(AE0.1) % (both in toluene).…”

“…[1b, [3][4][5] Cyclometalated iridium(III) complexes are widely exploited because of their excited-state lifetimes on the microsecond time scale, high quantum yields, good thermal and chemical stability, and tunability of the emission color. [6][7][8][9][10] In this context, the prototype complex is fac-[Ir(ppy) 3 ] (ppy = 2-phenylpyridine).…”