Amplifying Circularly Polarized Light Emission and Detection via Nonerosive Hetero-Ligand Complexation Doping in...

Nonerosive lattice doping of chiral self-assembly is advantageous for applications in polarized optoelectronics, as it evades the packing of molecular rearrangements that preserve the optical activity of microcrystals. However, present chiral microcrystals of phosphine-involved clusters often suffer from low quantum yields and dissymmetry factors (g_lum) of circularly polarized phosphorescence (CPP), due to limited control over the electromagnetic dipole moment and assembly compatibility of the host and guest. Here, we use chiral diphosphines and trace triphenylphosphines (TPPs) to govern the coordination and nonerosive doping of the binuclear Cu(I) clusters, as demonstrated with a family of heterogeneously doped hexagonal microcrystals based on (R)/(S)-Cu. Green CPP employing one of these pure (R)/(S)-Cu achieves a PLQY and g_lum of 5.7% and ±0.006, respectively, while the isostructural (R)/(S)-Ag emits similar CPP with lower PLQY (3.5%) and g_lum values (±0.004), which is caused by excited state deformation and weaker H-bonding. By further preparing crystals through trace doping of TPPs, all crystals feature the same hexagonal morphologies, but phosphorescence enhancement from trace heteroligand-chelated complexes and electronic configurations enables extra triplet populations and decay channels. Thus, the crystals show enhanced PLQYs for red-shifted CPP, as well as better CPL detection (g_res = 0.17) and scintillator imaging abilities.