Effects of N-heteroaromatic ligands on highly luminescent mononuclear copper(I)–halide complexes

Simple cuprous iodide complex‐based crystals with deep blue emission and high photoluminescence quantum yield up to 100%

“…The compound CuI (PPh 3 ) 2 (IQu) showed a maximum emission wavelength of 518 nm, corresponding to a green emission, and about 60 nm red‐shift compared with CuI (PPh 3 ) 2 ( t ‐BuPy), and a high PLQY of 79.0% in crystalline powder at room temperature (Figure b). Interestingly, CuI (PPh 3 ) 2 (IQu) showed emission with vibronic structure and an ultra‐long decay lifetime of 1220 μs at room temperature, and this can even be increased to 3041 μs at 77 K, which suggests 3 π‐π* character of the luminescence . Similarly, CuI (PPh 3 ) 2 (IQu) showed red‐shifted emission spectrum and decreased PLQY in thin film at room temperature, non‐luminescent at room temperature, and bright emission and blue shifted emission spectrum in 2‐MeTHF at 77 K (Figure b).…”

“…Recently, Kato et al developed a series of simple and efficient mononuclear cuprous halide complexes, and systematically studied the effect of N-heteroaromatic ligand, halide and temperature on the photophysical properties of these compounds. [30][31][32][33] Among these, the bluest emission complex is CuI (PPh 3 ) 2 (4-MePy) (PPh 3 = triphenylphosphine, 4-MePy = 4-methylpyridine), showing a maximum emission wavelength at 455 nm and a PLQY of 66% in crystals. [31] Huang et al also reported simple mononuclear cuprous halide complexes with deeper blue emissions and moderate PLQYs, i.e.…”

Mechanochromic Switching between Delayed Fluorescence and Phosphorescence of Luminescent Coordination Polymers Composed of Dinuclear Copper(I) Iodide Rhombic Cores

“…It is well known that in order for the Cu I complex to achieve high emission quantum yield, the Jahn–Teller flattening distortion of the MLCT excited state should be suppressed . The wide emission color tuning ranging from blue to red has been also achieved by the modification of the π* orbitals of the organic ligands . Since the photoexcited electron and the remaining hole are spatially separated in the π* orbital of the organic ligand and the 3d orbital of the Cu I ion, the energy gap between the single and triplet MLCT excited states tends to be small enough to permit an inverted intersystem crossing from the stable T 1 to relatively unstable S 1 state, resulting in TADF .…”

“…[31][32][33][34][35][36][37][38] The wide emission color tuning rangingf rom blue to red has been also achieved by the modificationo ft he p*o rbitals of the organic ligands. [39][40][41] Since the photoexcited electron and the remaining hole are spatially separated in the p*o rbitalo ft he organic liganda nd the 3d orbital of the Cu I ion, the energyg ap betweent he single and tripletM LCT excited states tends to be smalle nought op ermita ni nverted intersystem crossing from the stable T 1 to relatively unstable S 1 state, resulting in TADF. [10][11][12][13][14][15][16] One of the other typical emissive states is the triplet cluster-centered ( 3 CC) excited state that is usually observed for the iodide-bridged Cu I cluster complexes.…”

Thermal and Mechanochemical Syntheses of Luminescent Mononuclear Copper(I) Complexes

“…[35] Although we temporarily assumed that such a dependence could be due to the slight difference in the crystal packing between 1-α and 1-, indicating that the isoquinoline complex has comparable energy levels of 3 ππ* and 3 MLCT states, to obtain more information, several photophysical measurements were conducted for complexes 2-4 containing isoquinoline derivatives. As shown in Figure 6, complexes 2 and 3 exhibit yellow and orange emissions under UV-light irradiation, but complex 4, bearing a nitro group attached to the isoquinoline ligand, hardly shows any emission.…”