Circularly polarized luminescence and nonlinear optical techniques have garnered considerable attention due to their minimal energy loss and superior optical penetration. However, there is still a lack of mature strategies for designing materials that combine these two exceptional optical properties. Herein, two chiral cofacial naphthalenediimide-based crystals and their enantiomers (R-2NDI-1/S-2NDI-1 and R-2NDI-2/S-2NDI-2) feature yellowish-green circular polarized luminescence emissions centered at ca. 525 and 550 nm, with the glum values as high as ±4.1 × 10–2 and ±6.1 × 10–2, as well as two-photon excited emissions centered at 525 and 530 nm, with two-photon absorption cross-section values at 770 nm up to 2.662 × 103 and 2.693 × 103 GM, respectively. Experimental results, theoretical calculations, and crystal structure analysis demonstrate that the observed circularly polarized luminescence and two-photon absorption arise from a synergistic intramolecular and intermolecular electronic coupling effect. This approach offers a promising strategy for the future development of multifunctional crystalline optical materials.
Lin et al. (Thu,) studied this question.