Synthesis and studies of blue light emitting polymers containing triphenylamine‐substituted fluorene and diphenylanthracene moiety

Abstract

Photoluminescent (PL) polymers containing triphenylamine-substituted fluorene and diphenylanthracene (DPA) units were synthesized by aromatic nucleophilic substitution reaction. The light emitting polymers (LEPs) contains hole-transporting triphenylamine (TPA) groups at the C-9 position of fluorene and DPA-emitting segments in the main chain. The obtained polymers were soluble in various organic solvents and thermally stable. The synthesized polymers were successfully characterized by elemental analyses, FTIR and, 1 H NMR spectroscopy. The electrochemical measurements and optical properties of the polymers were also studied. The obtained polymers showed significant blue emission.

Novel Blue‐Emitter‐Containing o‐Terphenyl‐Substituted Fluorene and Diphenylanthracene Units

“…The polydispersity index (PDI) was calculated using number average molecular weight (Mn) and weight average molecular weight (Mw) approximately comes around 1 indicating uniform and one length of polymers. [13] This observation indicated that the polymers synthesized in the present investigation were nonbranching. The combination of GPC and NMR was used to confirm the structures and molecular weights of polymers by calculating the ratio of the integration of protons from the NMR spectrum of the polymers.…”

“…The structural characterization of the monomers was done by 1 H, 13 C NMR, and FTIR spectroscopy. The first significant feature of the infrared spectra of polymers ( Figure S3) was the absence of absorption peaks in the region 3400 cm À 1 indicating completion of polymerization and termination of the terminal hydroxy group of alkyl substituted DPA monomers.…”

“…The maximum intensity peaks were obtained in the wavelength range of 433-445 nm which is characteristic for blue emission. [13] This may be due to the increased solubilizing effect caused by alkyl attachments. An intense fluorescence was exhibited on UV excitation by the solution of polymers as shown in Table 1.…”

“…Therefore, OLEDs containing diphenylanthracene are expected to have a higher electroluminescence quantum yield, more lifetime blue emission and good device properties. [13,14] Hence, the present work is based on synthesis of a blue light emitting copolymer containing a Diphenylanthracene unit attached alternately to a fluorene unit containing terphenyl moiety.…”

Fluorescent, electroactive, thermally stable triphenylamine‐ and naphthalene‐based polyimides for optoelectronic applications

“…It is well established that the electronic strength of the substitution (electron‐donating or electron‐withdrawing nature) affects the electrochemical properties of materials containing the TPA moiety. According to the Hammet equation, electron‐donating groups, mainly at the para orientation of the TPA unit, exert a driving force in radical cation formation and stabilize it efficiently . However, electron‐withdrawing substituents have the opposite impact .…”