Bay-Substitution Effect of Perylene Diimides on Supramolecular Chirality and Optoelectronic Properties of Their Self-Assembled Nanostructures

Abstract

One-dimensional (1D) organic chiral supramolecules have received a great deal of attention for their promising applications in chiral recognition systems, chemical sensors, catalysts, and optoelectronics. Compared to modifications at the imide position of a perylene diimide (PDI), few studies have explored bay substitution of chiral PDIs and their self-assemblies into 1D nanomaterials. Herein, we describe the synthesis of three bay-substituted PDIs and explore the effects of bay substitution on supramolecular chirality by examining circular dichroism spectra and the optoelectronic performance of chiral PDI nanomaterials in phototransistors. Among the three fabricated self-assemblies, nanomaterials based on (R)-CN-CPDI-Ph exhibited the highest electron mobility of 0.17 cm2 V–1 s–1, a low threshold voltage of −1 V, and enhanced optoelectronic performance. For example, the photoresponsivity and external quantum efficiency of (R)-CN-CPDI-Ph assemblies were 4-fold higher than those of (R)-2Br-CPDI-Ph and (R)-2F-CPDI-Ph. All three nanomaterials exhibited fast switching speeds compared with previously reported N-substituted PDIs, suggesting that bay substitution can be an effective means of achieving rapid photoswitching. A comprehensive study using density functional theory calculations and crystal analyses revealed that the enhanced optoelectronic performance of (R)-CN-CPDI-Ph nanomaterials is related to the substitution of CN at the bay position of PDI. This minor change provides simultaneous improvements in electron injectability and structural order. Our findings demonstrate that bay substitution can significantly impact the self-assembly, supramolecular chirality, and optoelectronic properties of PDI nanomaterials.

Chirality Amplification Over the Morphology Control of the Rod-Coil Molecules with Lateral Methyl Groups

“…In supramolecular systems, lateral groups can mediate and significantly amplify molecular chirality via self-assembly. For example, the introduction of side-chain methyl groups into rod-coil molecules induces steric hindrance to the tight packing of molecules, thereby inducing supramolecular chirality. , In addition, opposite lateral groups may cancel each other to form racemates, reducing supramolecular chirality. − …”

Self-organizing maps as a data-driven approach to elucidate the packing motifs of perylene diimide derivatives

“…32 Furthermore, several other works, both experimental and theoretical, have been published on the effects of different substituents on the material performance of PDIs for specific applications, for example, the use of linear chains, 3,40 fluorinated chains 41 or branched chains 3,42,43 at the imide position and the use of cyano substituent, 44 halogenated substituents 45 or other substituents at the core. 24,46 Most of the works mentioned above mainly used dimer approaches based on reduced data sets of similar molecules, because analysis of the large target molecules leads to high computational costs. Recent advances in computational power and the development of smart algorithms in the field of machine learning and artificial intelligence are helping overcome the limitations of the dimeric approach.…”

“…32 Furthermore, several other works, both experimental and theoretical, have been published on the effects of different substituents on the material performance of PDIs for specific applications, for example, the use of linear chains, 3,40 fluorinated chains 41 or branched chains 3,42,43 at the imide position and the use of cyano substituent, 44 halogenated substituents 45 or other substituents at the core. 24,46…”

Synthesis of 1,6/7‐(NO2)2‐Perylenediimide and 1,6/7‐(NH2)2‐Perylenediimide as Regioisomerically Pure Materials**

“…[3] They can be found in a variety of organic electronics devices as active materials such as Organic Solar Cells (OSCs) as Non-Fullerene-Acceptors (NFAs) [4,5] or Electron Transporting Layer [6,7] for example and they are rising in chiral optoelectronics applications. [8] The choice of imide side-chain usually controls their self-assembly and solubility, [9] while the modification of their ortho and bay positions drastically change their optical and electronic properties: [10,11] in consequence, an intense synthetic work has been made to introduce various chemical functionalities and extend/dope their aromatic core. [12][13][14][15] The most popular and widespread strategy to functionalize the bay position is to first perform an halogenation.…”