Exceptionally fast radiative decay of a dinuclear platinum complex through thermally activated delayed fluorescence

Abstract

A novel dinuclear platinum(II) complex featuring a ditopic, bis-tetradentate ligand has been prepared. The ligand offers each metal ion a planar O^N^C^N coordination environment, with the two metal ions bound...

Diazine-based thermally activated delayed fluorescence chromophores

“…ITO/ HATCN (10 nm)/ a-NPD (30 nm)/mCP (5 nm)/6 wt% emitter-doped PPT(30 nm)/ TPBi (40 nm)/LiF (0.8 nm)/Al (80 nm) b ITO/TAPC (30 nm)/ TcTa (5 nm)/CBP: TADF emitters (6 wt %, 15 nm)/ Tm3PyPB (65 nm)/LiF (1 nm)/Al (100 nm) c ITO/MoO 3 (1 nm)/1,1-bis[(di-4-tolylamino)phenyl]-cyclohexane (60 nm)/N,N-dicarbazolyl-3,5-benzene (10 nm)/ mCPCN: TADF emitters (6 wt %, 20 nm)/tris-[3-(3-pyridyl)mesityl]borane (55 nm)/LiF (1 nm)/Al d ITO/TAPC (30 nm)/ TcTa (5 nm)/10 wt % TADF emitter:DPEPO (15 nm)/ TmPyPB (65 nm)/ LiF (0.8 nm)/Al (100 nm) e no data provided Very recently, some Ir(III) and Pt(II) metal complexes of pyrimidine-based ligands exhibiting TADF properties were also described (Chart 19). 91,92,93,94 Within these complexes, the TADF nature of the emission was demonstrated by a strong decrease of photoluminescence intensity below 230 K. It appears that, unlike mononuclear analogues, bimetallic structures tend to promote favorable conditions for the occurrence of TADF due to smaller DE ST and larger singlet oscillator strength. The replacement of chlorine by iodine as ancillary ligand in complex Pt3 results in a more pronounced reduction of DE ST .…”

Enhancement of thermally activated delayed fluorescence properties by substitution of ancillary halogen in a multiple resonance-like diplatinum(ii) complex

“…Most strikingly however, the photoluminescence and absorption spectra of 3 clearly overlap, indicating that the emissive state might be associated with a radiative transition possessing large oscillator strength (ε ~10 4 M -1 cm -1 ), such as of singlet and not triplet character. 11,23,26,28 On the other hand, 4 presents a typical picture of a phosphorescent transition metal complex with a relatively large apparent Stokes shift and no overlap of the emission spectrum with transitions of high oscillator strength. As this behaviour of complex 3 is in common Please do not adjust margins Please do not adjust margins with other recently discovered diplatinum(II) complexes 26,28 that demonstrate TADF properties, we have studied the temperature-dependent behaviour of its photoluminescence in toluene solution (Figure 3 and Figure 4).…”

“…11,23,26,28 On the other hand, 4 presents a typical picture of a phosphorescent transition metal complex with a relatively large apparent Stokes shift and no overlap of the emission spectrum with transitions of high oscillator strength. As this behaviour of complex 3 is in common Please do not adjust margins Please do not adjust margins with other recently discovered diplatinum(II) complexes 26,28 that demonstrate TADF properties, we have studied the temperature-dependent behaviour of its photoluminescence in toluene solution (Figure 3 and Figure 4). The photoluminescence intensity of 3 increases by ~25 % upon decreasing the temperature from 300 to 230 K, which is attributed to the suppression of non-radiative decay pathways affecting the triplet state.…”

“…13,14 So far, TADF properties have been found in a plethora of metal-free compounds 15,16 as well as in organometallic complexes of Cu(I), [17][18][19] Ag(I), 20 Au(I) 21 and Pd(II) 11,22,23 , but lesser known examples involving other metal ions such as W(VI) 24 or Sn(IV) 25 also exist. The latest discovery of TADF properties in dinuclear platinum(II) 26 and of somewhat similar behaviour in di-and mononuclear iridium(III) 27 complexes has demonstrated that large radiative rates can be obtained without the need for strong SOC from the metal. Further research has indicated that dinuclear complexes of platinum(II) are more likely to demonstrate TADF than their mononuclear counterparts, as the former have smaller ΔE ST and larger S 1 S 0 radiative rates -factors crucial for efficient delayed fluorescence.…”

Bipolar Molecules with Hybridized Local and Charge‐Transfer State for Highly Efficient Deep‐Blue Organic Light‐Emitting Diodes with EQE of 7.4% and CIEy ∼ 0.05

“…Organic light-emitting diodes (OLEDs) have been attracting great interests for their wide application in full color displays and lighting devices. [1][2][3][4][5][6][7][8][9][10][11][12][13] However, scarcity of efficient and stable blue emitters is still the bottle-neck for the development of OLEDs. Blue phosphorescent materials and thermally activated delayed fluorescence (TADF) materials can theoretically acquire 100% internal quantum efficiency (IQE) by harvesting both singlet and triplet excitons and they are so far the most practical and most promising materials, respectively.…”