Synthesis, characterization, physical properties, and applications of highly fluorescent pyrene-functionalized 9,9-bis(4-diarylaminophenyl)fluorene in organic light-emitting diodes

A new, highly fluorescent pyrene-functionalized 9,9-bis(4-diarylaminophenyl)fluorene, namely PTF, was synthesized and characterized. This material is an amorphous molecular glass with notably high T_g, is electrochemically stable, and exhibits strong blue emission both in solution and solid state. It shows promising ability as a solution processed blue emitter and hole-transporter for OLEDs. High-efficiency sky-blue and Alq3-based green devices with luminance efficiencies of 1.13 and 4.08 cd/A are achieved, respectively.     

Synthesis and properties of oligofluorene-thiophenes as emissive materials for organic electroluminescent devices: color-tuning from deep blue to orange

A series of oligofluorene-thiophenes end-capped with 3,6-di-tert-butylcarbazole and pyrene were designed and synthesized for application as color tunable emissive materials for organic electroluminescent devices. They were characterized by ¹H NMR, ¹³C NMR, FT-IR, UV–vis, PL spectroscopy, and mass spectrometry. Theoretical calculations revealed that the carbazole moiety attached to the end of the molecule is nearly perpendicular to oligofluorene-thiophene-pyrene plane and π-electrons in the ground state delocalize over the entire molecule. Their optical, thermal, and electrochemical properties could be tuned by varying the number of thiophene units in the molecule. All were electrochemically and thermally stable molecules. OLED devices of these materials emitted brightly in various colors from deep blue to orange. Particularly, deep blue (CIE coordinates of 0.16, 0.14) and green (CIE coordinates of 0.27, 0.61) devices showed high color quality close to the NTSC standards with high luminance efficiencies of 1.14 and 11.15 cd/A, respectively.     

Modification of D–A–π–A Configuration toward a High‐Performance Triphenylamine‐Based Sensitizer for Dye‐Sensitized Solar Cells: A Theoretical Investigation

In an attempt to shed light on how the addition of a benzothiadiazole (BTD) moiety influences the properties of dyes, a series of newly designed triphenylamine‐based sensitizers incorporating a BTD unit as an additional electron‐withdrawing group in a specific donor–acceptor–π‐acceptor architecture has been investigated. We found that different positions of the BTD unit provided significantly different responses for light absorption. Among these, it was established that the further the BTD unit is away from the donor part, the broader the absorption spectra, which is an observation that can be applied to improve light‐harvesting ability. However, when the BTD unit is connected to the anchoring group a faster, unfavorable charge recombination takes place; therefore, a thiophene unit was inserted between these two acceptors, providing redshifted absorption spectra as well as blocking unfavorable charge recombination. The results of our calculations provide valuable information and illustrate the potential benefits of using computation‐aided sensitizer design prior to further experimental synthesis.