Color‐ and Dimension‐Tunable Light‐Harvesting Organic Charge‐Transfer Alloys for Controllable Photon‐Transport Photonics

Abstract

An electron donor/acceptor pair comprising perylene (Pe) and 9,10‐dicyanoanthracene (DCA) was specifically designed to construct organic charge‐transfer (CT) alloys via weak CT interaction through a solution co‐assembly route. By adjusting the molar ratio between Pe and DCA, we achieve color‐ and dimension‐tunable CT alloy assemblies involving one‐dimensional (1D) (DCA)1−x(Pe)x (0 ≤ x ≤10 %) microribbons and two‐dimensional (2D) (Pe)1−y(DCA)y (0 ≤ y ≤5 %) nanosheets as a consequence of energy transfer from DCA or α‐Pe to Pe‐DCA CT complex. Importantly, dimension‐related optical waveguiding performances are also revealed: continuously adjustable optical loss in 1D (DCA)1−x(Pe)x microribbons and successive conversion from isotropic waveguide to anisotropic waveguide in 2D (Pe)1−y(DCA)y nanosheets. The present work provides a desired platform for in‐depth investigation of light‐harvesting organic CT alloy assemblies, which show promising applications in miniaturized optoelectronic devices.

Tuning of bandgaps and emission properties of light-emitting diode materials through homogeneous alloying in molecular crystals

“…A commonly reported class of solid solution/alloy crystals are formed between planar aromatic molecules as donoracceptor charge transfer complexes, where two or more electron-acceptor molecules are sandwiched between planar aromatic electron donor molecules. 15,18,27 Hence the individual crystal structures of the electron-acceptor molecules are not a crucial factor in the alloy formation. On the contrary, for nonplanar molecules to form alloys, isostructurality of the crystal structures of individual components is an important structural criterion.…”

“…17 In the context of photophysical properties of molecular alloys, Fu et al demonstrated the tuning of photoluminescence emission and optical waveguiding performances of charge transfer alloy crystals formed by perylene and 9,10-dicyano-anthracene (DCA) 1-x (Pe) x . 18 Although the composition range of the alloy components in these examples were limited to < 10 %, this report points to the prospects of achieving desirable tuning of photophysical properties if high composition ranges could be achieved in molecular alloys. In this article, we report the crystalline molecular alloys formed by organic light-emitting diode (OLED) materials Mq 3 , where M= Al, Ga, In, and Cr and q = 8-hydroxyquinoline ligand.…”

Optical Waveguides in Organic Crystals of Polycyclic Arenes

“…[45] Another case showed by Fu's group was about the optical waveguide in the so-called organic CT alloys. [46] An electron donor/acceptor pair comprising perylene (Pe, Figure 31A,C) and DCA (Figure 31B,D) were integrated together to create CT complex. The complex could act as an energy acceptor and was sensitized by an energy donor, giving rise to a highly efficient energy transfer process.…”

“…Additionally, all the molecular structures and the performance of the corresponding optical waveguiding crystals mentioned above are summarized in Table 1, which is specifically categorized according to the size of the crystals. [46] Copyright 2020, Wiley-VCH.…”

“…E) Diagram of two types of organic alloy assemblies involving (DCA) 1−x (Pe) x and (Pe) 1−y (DCA) y . Reproduced with permission [46]. Copyright 2020, Wiley-VCH.…”