Noncovalent Se···O Conformational Locks for Constructing High-Performing Optoelectronic Conjugated Polymers.

Area of Science:

• Materials Science
• Organic Electronics
• Supramolecular Chemistry

Background:

• Noncovalent conformational locks are crucial for planar π-conjugated semiconductors, enhancing charge transport.
• Current chalcogen-based strategies primarily use weak sulfur-oxygen/nitrogen/halide interactions.
• There is a need for novel, effective conformational locks in organic semiconductor design.

Purpose of the Study:

• To design and synthesize a novel selenophene-based building block with strong Se···O noncovalent conformational locks.
• To develop stable, planar, and solution-processable conjugated polymers using this new building block.
• To evaluate the performance of these polymers in organic electronic devices.

Main Methods:

• Design and synthesis of 1,2-diethoxy-1,2-bisselenylvinylene (DESVS) building block.
• Computational studies (DFT) for electronic structure analysis.
• Single crystal X-ray diffraction and experimental lattice cohesion measurements.
• Polymer synthesis and device fabrication (organic thin-film transistors and organic photovoltaic cells).

Main Results:

• Successful synthesis of the DESVS building block featuring novel Se···O locks.
• Demonstration of unique electronic properties and structural planarity of DESVS.
• Fabrication of stable, planar, solution-processable conjugated polymers.
• Achieved high carrier mobilities (1.49 cm² V⁻¹ s⁻¹ p-type, 0.65 cm² V⁻¹ s⁻¹ n-type) in organic thin-film transistors.
• Obtained power conversion efficiencies exceeding 5% in organic photovoltaic cells.

Conclusions:

• The novel DESVS building block effectively utilizes Se···O noncovalent locks to achieve high planarity and charge transport.
• DESVS-based polymers represent a promising new class of materials for high-performance organic electronics.
• This work expands the scope of conformational lock strategies in organic semiconductor design.