Title : Role of side chains in charge localization and transfer in azothiazol-dithiophene conjugated copolymers
Abstract:
Charge localization across conjugated polymers is one of the most important features to control their overall photo-physical processes including the intermolecular charge transfer (CT) with molecular acceptors at interfaces. Herein, we synthesize two azothiazole (ATz) conjugated polymers coupled with a dithiophene (BT) donor using either esters or non-esters as side chains. The non-ester side chain polymer (P1ATz-BT) shows a strong emission quenching upon successful addition of 1,4-dicyanobenzene (DCB), as a molecular acceptor, via intermolecular CT. On the other hand, the ester side-chain polymer (P2ATzE-BT) does not exhibit such changes, indicating that the side chain has a significant impact on the photo-physical processes of these polymers at the interface with molecular acceptors. Density functional theory (DFT) calculations and time-resolved photoluminescence measurements show that, unlike P1ATz-BT, the introduction of ester chains causes significant steric effects on the conformation of polymer backbones and the localization of electron density distributions in P2ATzE-BT, which leads to the suppression of the charge transfer to the molecular acceptor. Our study provides the first experimental and theoretical clues for understanding the tremendous impact of polymer side chains on photo-physical processes with molecular acceptors, at interfaces. These findings pave the way towards controlling and optimizing the interfacial charge transfers in conjugated polymers.
Audience Take-Away:
- The audience will understand how the side chain of such copolymers can affect the charge transfer.
- This will help the audience choose the correct materials for photovoltage devices.
- Yes, this provides a practical solution to a problem that could simplify or make a designer’s job more efficient
- Yes, it will improve the accuracy of a design, or provide new information to assist in a design problem
