Efficient Intramolecular Charge‐Transfer Fluorophores Based on Substituted Triphenylphosphine Donors

Triphenylphosphine (TPP)‐based luminescent compounds are rarely investigated because of the low photoluminescence quantum yield (PLQY). Here, we demonstrate that introducing steric hindrance groups to the TPP moiety and separating the orbitals involved in the transition can drastically suppress the non‐radiative decay induced by structural distortion of TPP in the excited state. High PLQY up to 0.89 as well as thermally activated delayed...