Theoretical Investigation and Molecular Design: A Series of Tripod-Type Cu(I) Blue Light Thermally Activated Delayed Fluorescence Materials

The photophysical properties and luminescent mechanism of a series of tripod-type Cu(I) complexes in solution and solids were comprehensively investigated through theoretical simulations. From a microscopic perspective, the experimental phenomenon is explained: (1) The intrinsic reason for the quenching of complex 1in solution was attributed to the significant nonradiative transition caused by structural deformation; (2) In the solid, the reduced ΔESTfor complex 2effectively facilitate reverse intersystem crossing (RISC) and improves its luminescence efficiency; (3) The enhanced performance of complex 3in solution is attributed to that its stronger steric hindrance is advantageous to decrease not only the ΔESTbut also the reorganization energy through intramolecular weak interactions. Based on complex 3, the tert-butyl substituted isomeric complex 4was designed. Complex 4further amplifies the advantages of 3to further promote the RISC to make full use of excitons. Meanwhile, it has an emission wavelength of 462.6 nm, which makes it an excellent candidate for high-efficiency deep-blue TADF materials. This study provides valuable information for obtaining efficient blue phosphorescence and TADF dual-channel luminescent materials.