Synthesis and Studies of Blue Light Emitting Polymers Containing Triphenylamine-Substituted Fluorene and Diphenylanthracene Moiety Kanchan A. Barve, Sambhaji S. Raut, Alok V. Mishra, Vishwanath R. Patil Department of Chemistry, University of Mumbai, Santacruz (E), Mumbai 400 098, India Received 1 September 2010; accepted 26 February 2011 DOI 10.1002/app.34408 Published online 25 July 2011 in Wiley Online Library (wileyonlinelibrary.com). ABSTRACT: Photoluminescent (PL) polymers containing triphenylamine-substituted fluorene and diphenylanthra- cene (DPA) units were synthesized by aromatic nucleo- philic 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. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 3483–3492, 2011 Key words: photoluminescent; triphenylamine-substituted fluorene; diphenylanthracene units; light emitting polymers INTRODUCTION Since the first use of photoluminescent (PL) poly- mers for light emitting diodes (LEDs) by Friend and coworkers, such polymers have stimulated tremen- dous research activity in the development of LEDs for display applications. 1–5 The emission color of these polymer can be easily tailored by modifying the molecular design of an organic material used in the polymer structures. However, one area of ongoing research is the quest for a stable blue-emit- ting material because efficient, highly bright and stable blue light is necessary for full color PL display application. 6,7 Triphenylamine (TPA)-substituted fluorene has been selected for the backbone of many light emit- ting polymers (LEPs) due to its large band gap, high photoluminescence, quantum efficiency, good ther- mal stability as well as good solubility. Fluorene containing polymers (polyfluorenes) also have emerged as an attractive alternative to other p conju- gated polymers for organic optoelectronics due to their strong blue emission, high charge mobility, and excellent chemical and thermal stability. Almost all polyfluorenes utilize side-chain substituents that improve solution processing as well as confer new functionality. Thermal cycling of polyfluorenes results in distinct backbone and side-chain confor- mations that lead to improved optical and electronic properties. 8 Numerous polyfluorenes with various co monomers have been developed with a view to obtaining stable, highly efficient, red, green, and blue emitters. Many studies of the introduction of charge transporting moieties into p conjugated poly- mers for efficient PLEDs have been reported. 5–7 It is known that the hole mobilities of most emissive p conjugated polymers are generally orders of magni- tude larger than their electron mobilities. 9 It was found that the separate attention is being given to the study of diphenylanthracene (DPA) and TPA- substituted fluorene containing polymers. Therefore, it was worthwhile to synthesize the LEPs where these two areas could be combined in novel way. Hence, the LEPs containing alternate TPA-substi- tuted fluorene and DPA segments in the backbone were synthesized. The synthesis and architecture of the polymers are based on the ether linkage in the backbone which gives the thermal stability and adjust the length of conjugation. In this article, we focus first on the incorporation of electrochemically stable DPA, a blue light emit- ting segment into the polymer molecule. 10–12 It is known that DPA has unit PL quantum yield, good electrochemical and chemiluminescence proper- ties. 13,14 It has also been reported that, the conjuga- tion length of the PL polymer could be effectively tailored by incorporating the non conjugation seg- ment or phenylene unit in the backbone. 15–20 This Correspondence to: V. R. Patil (vishwanathrpatil03@gmail. com). Journal of Applied Polymer Science, Vol. 122, 3483–3492 (2011) V C 2011 Wiley Periodicals, Inc.