Molecular Gridization of Organic Semiconducting π Backbones

Area of Science:

• Materials Science
• Organic Electronics
• Nanotechnology

Background:

• Organic semiconductors offer unique properties but face challenges in performance, stability, and processing.
• Nanosization of π-conjugated systems is a key strategy to overcome molecular limitations.
• Organic nanogridarenes (ONGAs) were introduced in 2014 as a covalent nanoscale strategy.

Purpose of the Study:

• To comprehensively review the progress in structural diversity, synthesis, and properties of ONGAs.
• To explore the impact of molecular gridization on the electronic and exciton properties of organic semiconductors.
• To highlight the potential applications of ONGAs in advanced organic electronic devices.

Main Methods:

• Definition of six types of monogrids and synthesis of various ONGA-based nanoatoms and nanomolecules.
• Exploration of shape-sensitive gridization rules using Friedel-Crafts, superelectrophile, and C-H activation reactions.
• Characterization of gridization effects on reorganization energy, thermal stability, charge transport, and dielectric properties.

Main Results:

• Gridization effectively reduces reorganization energy (ROE), with multigridization achieving ROE below 28 meV.
• ONGAs exhibit modulated thermal stability, excited-state pathways, charge mobility, and dielectric characteristics.
• Demonstrated applications include ultraviolet OLEDs with ~4.12% external quantum efficiency and organic field-effect transistor memory devices with long retention times.

Conclusions:

• Molecular gridization of π backbones is a powerful strategy to enhance organic semiconductor performance and stability.
• ONGAs possess unique properties making them suitable for flexible OLEDs and organic neuromorphic computing.
• Future research directions focus on organic electronic intelligence and scaling supercycles using AI and robotic chemists.