Emissive BN-Embedded Cumulenes: Synthesis and Bidirectional Photocurrent Modulation

Area of Science:

• Materials Science
• Organic Chemistry
• Optoelectronics

Background:

• Boron and nitrogen (BN) embedding tunes electronic structures in π-conjugated systems.
• BN-embedding is explored in C(sp2) polyaromatic hydrocarbons but less in C(sp)-rich systems.
• Optoelectronic properties of C(sp)-rich systems with BN remain underexplored.

Purpose of the Study:

• Investigate the impact of BN-embedding on C(sp)-rich systems.
• Synthesize and characterize BN-capped sp-carbon chains isoelectronic to cumulenes.
• Explore the optoelectronic properties and device applications of these novel materials.

Main Methods:

• Synthesis of air- and moisture-stable BN-capped sp-carbon chains ([n]BN, n=3, 5).
• Structural and spectroscopic analyses (e.g., X-ray diffraction, NMR, UV-Vis, fluorescence spectroscopy).
• Fabrication and characterization of heterojunction optoelectronic devices incorporating [3]BN.

Main Results:

• BN-embedding induces pronounced electronic polarization and localizes skeletal vibrations.
• [n]BN chains exhibit strong excimer-like solid-state fluorescence, unlike their all-carbon analogs.
• Devices with [3]BN show unique bidirectional photocurrent modulation due to excited-state charge separation and asymmetric carrier injection.

Conclusions:

• BN-embedding is a viable strategy to tune electronic structure and properties of C(sp)-rich systems.
• BN-capped cumulenes possess unique optoelectronic functionalities.
• This work opens avenues for developing novel functional materials based on BN-embedded C(sp)-rich frameworks.