Protein‐like Enwrapped Perylene Bisimide Chromophore as a Bright Microcrystalline Emitter Material

Abstract

Strongly emissive solid‐state materials are mandatory components for many emerging optoelectronic technologies, but fluorescence is often quenched in the solid state owing to strong intermolecular interactions. The design of new organic pigments, which retain their optical properties despite their high tendency to crystallize, could overcome such limitations. Herein, we show a new material with monomer‐like absorption and emission profiles as well as fluorescence quantum yields over 90 % in its crystalline solid state. The material was synthesized by attaching two bulky tris(4‐tert‐butylphenyl)phenoxy substituents at the perylene bisimide bay positions. These substituents direct a packing arrangement with full enwrapping of the chromophore and unidirectional chromophore alignment within the crystal lattice to afford optical properties that resemble those of their natural pigment counterparts, in which chromophores are rigidly embedded in protein environments.

Base‐Assisted Imidization: A Synthetic Method for the Introduction of Bulky Imide Substituents to Control Packing and Optical Properties of Naphthalene and Perylene Imides

“…We note that these solid‐state fluorescence spectra are likely affected by reabsorption losses, in particular for the (0,0) fluorescence band, which is known for dyes with small Stokes shifts and strong absorbance. Therefore, the obtained effective fluorescence quantum yields represent the lower limit of the intrinsic quantum yields . The strongest fluorescent PBI 9 d exhibits also the most pronounced vibronic progression in its solid‐state fluorescence spectrum (Figure S16).…”

“…We note that these solid-state fluorescence spectra are likely affected by reabsorption losses,i np articular for the (0,0) fluorescence band, which is known for dyes with small Stokes shifts and strong absorbance.T herefore,t he obtained effective fluorescence quantum yields represent the lower limit of the intrinsic quantum yields. [15] Thes trongest fluorescent PBI 9d exhibits also the most pronounced vibronic progression in its solidstate fluorescence spectrum ( Figure S16). This can be ascribed to emission from isolated monomer-like species due to the largest steric demand of the imide substituent, thereby impeding any p-p-contact between the perylene bisimide pscaffolds of neighbouring dyes (Figure 2c,d).…”

“…Forschungsartikel strates the utility of sterically demanding imide substituents to control the solid-state properties of this class of rylene imide dyes.The application of these and other sterically demanding imide substituents for solid-state emitters, [13,15] in solar light concentrators [11,12] and in photonic devices [14,39] is expected. We further expect that our new method might be applicable for the functionalization with larger dendrons for solubilization of theses dyes in water, [5] for example,t hrough clickchemistry of alkyne-containing moieties.…”

“…Furthermore,b yi ntroducing much bulkier aryl groups,s uch chromophores can crystallize in an isolated packing arrangement, allowing their use as solid-state emitters. [12,13] ForPBIs bulky substituents can be introduced either at the bay-positions, [14,15] ortho-positions [16,17] or the imide-positions. [12,13,18,19] Thelast is ideal for preserving the original properties of perylene dyes [13] and allows the introduction of additional substituents at the rylene scaffold to tune the optical and the electronic characteristics.…”

Base‐Assisted Imidization: A Synthetic Method for the Introduction of Bulky Imide Substituents to Control Packing and Optical Properties of Naphthalene and Perylene Imides

“…strates the utility of sterically demanding imide substituents to control the solid-state properties of this class of rylene imide dyes.The application of these and other sterically demanding imide substituents for solid-state emitters, [13,15] in solar light concentrators [11,12] and in photonic devices [14,39] is expected. We further expect that our new method might be applicable for the functionalization with larger dendrons for solubilization of theses dyes in water, [5] for example,t hrough clickchemistry of alkyne-containing moieties.…”