Theoretical\nInvestigation and Molecular Design: A\nSeries of Tripod-Type Cu(I) Blue Light Thermally Activated Delayed\nFluorescence Materials

The photophysical properties and\nluminescent mechanism\nof a series\nof tripod-type Cu(I) complexes in solution and solids were comprehensively\ninvestigated through theoretical simulations. From a microscopic perspective,\nthe experimental phenomenon is explained: (1) The intrinsic reason\nfor the quenching of complex <b>1</b> in solution was attributed\nto the significant nonradiative transition caused by structural deformation;\n(2) In the solid, the reduced Δ<i>E</i><sub>ST</sub> for complex <b>2</b> effectively facilitate reverse intersystem\ncrossing (RISC) and improves its luminescence efficiency; (3) The\nenhanced performance of complex <b>3</b> in solution is attributed\nto that its stronger steric hindrance is advantageous to decrease\nnot only the Δ<i>E</i><sub>ST</sub> but also the reorganization\nenergy through intramolecular weak interactions. Based on complex <b>3</b>, the <i>tert</i>-butyl substituted isomeric complex <b>4</b> was designed. Complex <b>4</b> further amplifies the\nadvantages of <b>3</b> to further promote the RISC to make full\nuse of excitons. Meanwhile, it has an emission wavelength of 462.6\nnm, which makes it an excellent candidate for high-efficiency deep-blue\nTADF materials. This study provides valuable information for obtaining\nefficient blue phosphorescence and TADF dual-channel luminescent materials.