Electron–electron repulsion in carbazole oligomer-attached tris (2,4,6-trichlorophenyl) methyl radicals

Authors:
Publisher website
Google Scholar
Abstract
Luminescent radicals are gathering much attention as a new class of luminescent material. We have synthesized a new carbazole oligomer (mono, di, tri, tetra) substituted luminescent tris (2,4,6-trichlorophenyl) methyl (TTM) radicals. The photoluminescence (PL) spectra showed emission stemmed from the excited state charge transfer character. Despite the increase in the highest occupied molecular orbital level of the carbazole oligomer associated with increasing the oligomer length, the PL maxima showed a blue shift from di- to tetra-oligomer substitution. This unexpected behavior was explained by quantum chemical calculations, including electron–electron repulsion. The electron–electron repulsion on the donor orbital decreases when the oligomer length increases and leads to the blue shift of the emission. The blue shift of the emission accompanied by an increase in the photoluminescence quantum yield by substituting a large π-conjugated donor to a TTM radical would be a unique method to control the photophysical property of the luminescent radical.
Funding Information
  • Japan Society for the Promotion of Science (JP23H02026, JP23H03966, JP22K05253, JP24K23082, JP24KJ1764)
  • Ministry of Education, Culture, Sports, Science and Technology (Network Joint Research Center for Materials and Devices, Dynamic Alliance for Open Innovation Bridging HumanEnvironment and Materials, JPMXP09A21AT0017)
  • MEXT|JST|Adopting Sustainable Partnerships for Innovative Research Ecosystem (JPMJAP2334)
  • MEXT|JST|SPRING (JPMJSP2136)

This publication has 44 references indexed in Scilit: