Bright and Color-Tunable Circularly Polarized Excimer Emission from Pre-Organized, Naphthalene Diimide Molecular...

Within the realm of organic materials, excimer emission has emerged as an efficient strategy for developing circularly polarized luminescence (CPL)-active systems, owing to its intrinsic combination of high brightness and large dissymmetry factors (g_lum). Nevertheless, progress with this approach has been constrained by limited color tunability and substrate scope, with red-emissive circularly polarized excimer emission remaining essentially unexplored. Herein, we demonstrate that core-substitution chemistry of naphthalenediimide (NDI) derivatives offers a versatile platform to achieve tunable excimeric CPL spanning the visible range, from 500 nm (green) to 650 nm (red), reported here for the first time. By employing cyclophane and clip-like pre-organized molecular architectures, excited-state chirality was effectively introduced, affording bright circularly polarized excimer emission with impressively high g_lum values of up to 4.0 × 10^-2 (green) and 1.5 × 10^-2 (red), along with remarkable CPL brightness. These results, combining outstanding brightness with the rare realization of red-emissive excimeric CPL, place these systems among the highest-performing small molecule CPL emitters to date.