Enhancing the phosphorescence decay pathway of Cu(I) emitters - the role of copper-iodide moiety

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

This work reports that ligand engineering can modulate the triplet harvesting mechanism in iodide-bridged rhombic Cu2I2 complexes. Complex-1, with a smaller Cu-Cu distance, exhibits phosphorescence from 3(M+X)LCT and 3CC states with 66% quantum yield, whereas an increased Cu-Cu distance in complex-2 results in a switch of the emission from phosphorescence to TADF, which occurs via 1/3(M+X)LCT states with 83% quantum yield. The TADF property of complex-2 has been utilized for the fabrication of a pc-LED emitting efficient warm white light. Moreover, the high charge-transfer nature of these complexes leads to the emergence of third-harmonic generation (THG). Interestingly, complex-1 exhibits efficient third-harmonic generation with a χ(3) value of 1.15 × 10-18 m2 V-2 and LIDT value of 14.73 GW/cm2. This work aims to provide a structure-property relationship to achieve effective harvestation of triplet excitons in iodide-bridged rhombic Cu2I2 complexes and their effective utilization in OLED device fabrication and nonlinear photon upconversion processes.

Structure and emission properties of dinuclear copper(i) complexes with pyridyltriazole

A new series of five highly emissive binuclear heteroleptic pyridyltriazole-Cu(i)-phosphine complexes 1-5 was synthesized and examined by different experimental (IR, elemental and thermogravimetric analysis, single crystal X-ray diffraction technique, UV-vis and fluorescence spectroscopy) and quantum chemical aproaches. Complexes 1-5 exhibited excellent stimuli-responsive photoluminescent performance in the solid state at room temperature (quantum yield (QY) = 27.5-52.0%; lifetime (τ) = 8.3-10.7 μs) and when the temperature was lowered to 77 K (QY = 38.3-88.2; τ = 17.8-134.7 μs). The highest QY was examined for complex 3 (52%) that can be explained by the small structural changes between the ground S₀ and exited S₁ and T₁ states leading to the small S₁-T₁ triplet gap and efficient thermally-activated delayed fluorescence. Moreover, complex 4 demonstrates reversible mechanochromic and excitation dependent luminescence.

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

Trigonal copper(i) complexes comprising cation–π interactions achieve satisfactory photoluminescence properties.