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Title: Electronic and optical properties of novel carbazole-based donor-acceptor compounds for applications in blue-emitting organic light-emitting diodes

We report that organic light-emitting diodes (OLEDs) have received a significant attention over the past decade due to their energy-saving potential. We have recently synthesized two novel carbazole-based donor-acceptor compounds and analyzed their optical properties to determine their suitability for use as blue emitters in OLEDs. These compounds show remarkable photo-stability and high quantum yields in the blue region of the spectrum. In addition, they have highly solvatochromic emission. In non-polar solvents, bright, blue-shifted (λmax ≈ 398 nm), and highly structured emission is seen. With increasing solvent dielectric constant, the emission becomes weaker, red-shifted (λmax ≈ 507 nm), and broad. We aim to determine the underlying cause of these changes. Electronic structure calculations indicate the presence of multiple excited states with comparable oscillator strength. These states are of interest because there are several with charge-transfer (CT) character, and others centered on the donor moiety. We theorize that CT states play a role in the observed changes in emission lineshape and may promote charge mobility for electrofluorescence in OLEDs. In the future, we plan to use Stark spectroscopy to analyze the polarity of excited states and transient absorption spectroscopy to observe the dynamics in the excited state.
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [4]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Wright State Univ., Dayton, OH (United States)
  4. Wright State Univ., Dayton, OH (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0277-786X
Grant/Contract Number:
SC00112704; AC02-98CH10886; CHE-1012529; CHE-1363050; CHE-1027985; CHE-1307117
Accepted Manuscript
Journal Name:
Proceedings of SPIE - The International Society for Optical Engineering
Additional Journal Information:
Journal Volume: 9549; Journal ID: ISSN 0277-786X
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; OLEDs; blue-emitters; carbazoles; donor-acceptor compounds
OSTI Identifier: