Cocrystallization-Promoted Charge Mobility in All-Conjugated Diblock Copolymers for High-Performance Field-Effect...

Area of Science:

• Materials Science
• Polymer Chemistry
• Organic Electronics

Background:

• Cocrystallization is a strategy to enhance material properties, but its application in all-conjugated block copolymers (BCPs) is underexplored.
• All-conjugated BCPs are promising for organic electronics due to their tunable properties.

Purpose of the Study:

• To investigate the relationship between cocrystal formation and charge mobility in poly(3-butylthiophene)-block-poly(3-hexylthiophene) (P3BT-b-P3HT) BCPs.
• To understand the influence of molecular weight and thermal annealing on the cocrystalline structure and charge transport properties of these BCPs.

Main Methods:

• Synthesis and characterization of P3BT-b-P3HT BCPs with varying molecular weights.
• Cocrystallization induced by thermal treatment.
• Measurement of charge carrier mobility.
• Analysis of crystallographic structure and morphology changes upon annealing.

Main Results:

• All rod-rod P3BT-b-P3HT BCPs formed cocrystals with higher charge mobilities than their homopolymers or blends.
• A 150 °C thermal treatment increased crystallinity and slightly improved charge mobilities in BCPs with higher molecular weights (15k, 18k, 28k).
• Lower molecular weight BCPs (P3BT-b-P3HT-12k) showed decreased mobility due to preferential alkyl stacking, while higher molecular weights showed slight increases due to pi-pi stacking.

Conclusions:

• Cocrystallization significantly promotes charge mobility in all-conjugated BCPs.
• The interplay between molecular weight, annealing conditions, and crystal packing dictates charge transport efficiency.
• These findings offer a pathway for designing high-performance organic electronic devices using cocrystalline BCPs.