Enhancing the phosphorescence decay pathway of Cu(i) emitters – the role of copper–iodide moiety

Abstract

Speeding up the phosphorescence channel in luminescent copper(I) complexes has been extremely challenging due to the copper atoms relatively low spin-orbit coupling constant compared to heavier metals such as Iridium....

Structural characterization and luminescence properties of trigonal Cu(i) iodine/bromine complexes comprising cation–π interactions

“…The radiative rate constant values ( k r ) for the Cu( i ) complexes 1 and 2 are calculated based on the formula k r (s −1 ) = Φ / τ to be 1.01 × 10 4 s −1 and 1.17 × 10 4 s −1 , respectively, which are comparable to those previously reported for Cu( i ) halide complexes. 48 Not surprisingly, complex 3 based on chloride exhibits weak luminescence ( λ em = 641 nm) with a lower PLQY of 14% and shorter decay lifetime of 17.1 μs. Obviously, the relatively slower radiative decay rate ( k r = 8.19 × 10 3 s −1 ) is due to a weaker SOC effect of chloride in comparison with those of iodine/bromine.…”

Activation of TADF in Photon Upconverting Crystals of Dinuclear Cu(I)-Iodide Complexes by Ligand Engineering

“…The exceptional increment in the emission intensity clearly shows that at low temperature, the emissive state has a much longer lifetime corresponding to phosphorescence emission. Furthermore, we have calculated the temperature-dependent contributions of delayed fluorescence and phosphorescence to the total emission along with delayed fluorescence lifetime by using eq , , and , respectively. , I ( T 1 ) I T o t = true[ 1 + k r ( S 1 ) 3 k r ( T 1 ) e − Δ E S T / k B T true] − 1 I ( S 1 ) I T o t = 1 − true[ 1 + k r ( S 1 ) 3 k r ( T 1 ) e …”

“…Furthermore, we have calculated the temperature-dependent contributions of delayed fluorescence and phosphorescence to the total emission along with delayed fluorescence lifetime by using eq 2, 3, and 4, respectively. 34,48 = +…”

“…The exceptional increment in the emission intensity clearly shows that at low temperature, the emissive state has a much longer lifetime corresponding to phosphorescence emission. Furthermore, we have calculated the temperature-dependent contributions of delayed fluorescence and phosphorescence to the total emission along with delayed fluorescence lifetime by using eq , , and , respectively. , where, k r ( S 1 ) and k r ( T 1 ) denote the rate of prompt fluorescence and the rate of phosphorescence, respectively. The temperature dependence of the TADF and phosphorescence attributes was found to follow a similar nature as the lifetime variation, which are complementary to each other (Figure h).…”