Naptha-phenanthroimidazole-based blue fluorophores (y

Abstract

Organic light-emitting diodes are a promising new technology for next-generation displays and lighting applications, particularly in the quest for efficient deep blue fluorophores (y= < 0.05). Despite the receipt of several reports, it remains imperative to advance the development of a deep blue emitter that can address solubility, stability, color purity, and efficiency. Eye on these challenges, herein, four new blue phenanthroimidazole and naphthalene-based derivatives, 2-(naphthalen-1-yl)-1H-phenanthro[9,10-d]imidazole(Pq-NH-NA), 2-(naphthalen-1-yl)-1-phenyl-1H phenanthro [9,10-d]imidazole (Pq-An-NA), 2-(naphthalen-1-yl)-1-(3-(trifluoromethyl)phenyl)-1H-phenanthro[9,10-d]imidazole (Pq-mF-NA), and 2-(naphthalen-1-yl)-1-(4-(trifluoromethyl)phenyl)-1H-phenanthro[9,10-d]imidazole (Pq-pF-NA) were designed and synthesized. Further, the PI molecules were structurally characterized by spectroscopic analysis, and their thermal decomposition (Td) is found to be 203–309 °C. Substitution at the N1 position of imidazole provides a facile alternative role for photophysical and electronic properties. The PI fluorophores were further characterized in solution, thin-film, and solid where the solid results are enhanced in terms of intense color emission (x = 0.158, y = 0.037). It showed a good quantum yield of 14.28 % in solution and 19.33 % in solid, indicating that fluorinated molecules lead to better performance than the rest of them. Additionally, the InGaN LED fabricated with the fluorinated molecule Pq-pF-NA emitted 425 nm with a deep blue emission and yielding CIE color coordinates (x = 0.154, y = 0.048). The film study also revealed the deep blue emission with increasing concentration of emitter (2.5 %). The observed results apprise that the synthesized fluorophores are efficient to deep blue emitters and capable candidates for organic light-emitting diodes.