Photoluminescent Anisotropy Amplification in Polymorphic Organic Nanocrystals by Light-Harvesting Energy Transfer

Abstract

Polymorphism and anisotropy are fundamental phenomena of crystalline materials. However, the structure-dependent photoluminescent (PL) anisotropy in polymorphic organic crystals has remained unexplored. Herein, two polymorphic nanocrystals, green-emitting nanorods (PtD-g) and yellow-emitting nanoplates (PtD-y), were obtained from a platinum­(II)−β-diketonate complex. The PtD-y crystals display remarkable PL anisotropy with an anisotropy ratio of up to 0.87 whereas the emission of the PtD-g crystals is nearly unpolarized. The polarization properties are rationalized on the different molecular packing of these crystals. By light-harvesting energy transfer, the PtD-y crystals are successfully used to amplify the emission polarization of a red-emitting platinum acceptor (PtA) doped into the donor crystalline matrix, which is otherwise weakly polarized as pure crystals.

Crossed 2D versus Slipped 1D π‐Stacking in Polymorphs of Crystalline Organic Thin Films: Impact on the Electronic and Optical Response

“…The device functionality of small‐molecule‐based organic optoelectronics depends strongly on the intermolecular arrangements as well as on morphological factors as intensively discussed in the past . This becomes apparent if the optical or electric response of different polymorphs of the same materials are considered . In particular, 2D arrangements—gathered via edge‐to‐face (herringbone) or slipped face‐to‐face (brickwork) packing motifs—were early realized as advantageous for efficient charge transport .…”

A Flexible Organic Single Crystal with Plastic‐Twisting and Elastic‐Bending Capabilities and Polarization‐Rotation Function

“…The maximum and minimum intensities appeared alternately, and the rotation angles for the maximum and minimum were perpendicular. These results indicate that the detected light was partly polarized . The straight crystal was then twisted to form, successively, angles of 30, 60, 90, 120, and 150° (Figure c) between the wider faces of the two ends (see the Supporting Information for the method realizing different twisting angles).…”

The Progress and Perspective of Organic Molecules With Switchable Circularly Polarized Luminescence

“…The switch processes work usually by controlling the assembly process, through tuning the solvent-solute interaction forces by tuning the polarity of the solvents, or by controlled cooling. Besides those widely applied stimuli, other methods not mentioned here make use of anions (Maeda et al, 2011;Zhao Z. H. et al, 2019), energy transfer (Feng et al, 2018;Sun M. J. et al, 2019), and stoichiometry (Li et al, 2019).…”