Mechano-Stimulus and Environment Dependent Circularly Polar-ized TADF in Chiral Copper(I) Complexes and their Application in OLEDs

Abstract

Molecular emitters that combine circularly polarized luminescence (CPL) and high radiative rate constants of the triplet exci-ton decay are highly attractive for electroluminescent devices (OLEDs) or next generation photonic applications, such as spintronics, quantum computing, cryptography or sensors. However, the design of such emitters is a major challenge because the criteria for enhancing these two properties are mutually exclusive. In this contribution, we show that enantiomerically pure [Cu(CbzR)((S/R)-BINAP)] (R = H (1), 3,6-tBu (2)) are efficient TADF emitters with high radiative rate constants of kTADF up to 3.1·105 s-1, and exceptional dissymmetry values of the emission glum of ±0.7·10-2 in THF solution and ±2.3·10-2 in the solid state are observed. Importantly for application in electroluminescence devices, the efficiency of the TADF pro-cess and emission wavelengths are highly sensitive to environmental hydrogen bonding of the ligands, which can be disrupt-ed either by grinding of the crystalline materials or by employing sterically bulky matrices. Accordingly, we have investigat-ed various matrix materials for successful implementation of the chiral copper(I) TADF emitters in proof-of-concept CP-OLEDs.