Soobin Ihm
Research Mentor: Richard Laine
Mentor Department: Materials Science and Engineering, Engineering
Author(s): Soobin Ihm, Zijing Zhang, Richard M. Laine
Session: Session 3 (11:00 AM – 11:50 AM)
Presentation Type: Poster 44
Abstract
Silicon-based hybrid materials are known to be effective insulators. However, we recently discovered that these materials show unique photophysical properties which imply their semiconducting properties. Polymers with Si-NH-Si backbones exhibit red-shifted emission compared to the corresponding silane model compounds, supporting efficient s–s* conjugation. Here, this research focuses on similar interactions in cyclotrisilazane copolymers and their efficiency compared to previously synthesized linear Si-NH-Si polymers. We expect cyclic silazanes to exhibit enhanced thermal and chemical stability compared to linear copolymers because the ring structure reduces chain mobility and bond rotation, preventing redistribution during synthesis. This stability of cyclotrisilazanes is why we expect it to be an effective optoelectronic material that retains its structure while preserving the electronically active Si-NH-Si backbone. This study specifically examines 1,3,5-trivinyl-1,3,5-trimethylcyclotrisilazane copolymer derivatives, which enable a direct test of through-ring conjugation in excited-state delocalization in Si-N systems, which are also analogous to through-ring conjugation previously identified in cyclosiloxane (Vy4D4) architectures. If delocalization extends around the Si–N ring, systematic red-shifts in emission with increasing degree of polymerization would provide strong evidence of s-conjugation across Si–N–Si units. The smaller ring size and increased rigidity may also improve orbital alignment, lower reorganization energy, and amplify delocalization. Finally, residual vinyl sites offer opportunities for secondary functionalization to further tune photophysical responses.
