Effect of Co-monomers on Triphenylamine-Thiazolothiazole-Based Donor-Acceptor Copolymers: Synthesis and their Optical Properties

Abstract

Donor‐Acceptor type copolymer, poly(9,9‐di‐n‐hexylfluorene‐alt‐2,5‐bis(N,N‐diphenylaniline)‐thiazolo[5,4‐d]thiazole) (P1) and random copolymers of P2‐P4 have been synthesized using Suzuki polymerization reaction. For random copolymers, dicyanomethane derivative of triphenylamine, dithienothiophene and thienothiophene were used as co‐monomers, respectively to P2‐P4 along fluorene and 2,5‐bis(N,N‐diphenylaniline)‐thiazolo[5,4‐d]thiazole). Studies on the optical, thermal and electrochemical properties of these copolymers (P1‐P4) were carried out. By incorporating different aromatic moiety as co‐monomer, optical properties of the polymers were tuned which exhibited significant changes in UV‐Vis absorption as well as emission characteristics. All these copolymers were thermally stable upto 300 °C and soluble in common organic solvents. Electrochemical studies of these polymers indicate that they have deep HOMO energy levels. Photoluminescence emission studies of the synthesized polymers as thin film showed that polymer (P2) with dicyanomethane derivative of triphenylamine was red shifted when compared with other polymers. Weight average moleular weights of the polymers were in the range of 6.457 KDa to 12.000 KDa.

Synthesis of Porphyrin‐Appended Poly(fluorene‐alt‐triphenylamine)s: Effect of Appending Groups on Optical and Electrochemical Properties

“…Monomers, 4‐[bis(4‐bromophenyl)amino]benzaldehyde and porphyrin appended 2,7‐Dibromo carbazole derivatives ( m ‐MTPPC and MTPPC) have been synthesized by our earlier reports ,,. Synthesis of polymers is shown in Scheme .…”

Highly electrochemically and thermally stable donor–π–acceptor triphenylamine-based hole-transporting homopolymersviaoxidative polymerization

“…8,33 The D-A strategy allows efficiently to regulate the energy of molecular orbitals, electrochemical bandgap, and absorption and emission spectra as well as to improve chargetransporting properties. [34][35][36][37][38] Various p-conjugated copolymers based on TPA have been studied 1,17,25,[39][40][41][42][43][44] including those with D-A structures. 34,39,42,44 However, the general drawbacks of D-A copolymers are that most of them are synthesized via cross-coupling reactions and using toxic organotin compounds as well as expensive catalysts based on noble metals.…”

“…[34][35][36][37][38] Various p-conjugated copolymers based on TPA have been studied 1,17,25,[39][40][41][42][43][44] including those with D-A structures. 34,39,42,44 However, the general drawbacks of D-A copolymers are that most of them are synthesized via cross-coupling reactions and using toxic organotin compounds as well as expensive catalysts based on noble metals. [44][45][46][47] These problems can be overcome using D-A homopolymers 27,48,49 instead of copolymers since the former can be prepared via rather simple oxidative polymerization.…”

Efficient organic photovoltaic cells based on thiazolothiazole and benzodithiophene copolymers with π‐conjugated bridges

“…Recently, conjugated polymers based on thiazolo[5,4‐ d ]thiazole (Tz) and various electron‐donating repeating units have been developed for polymer solar cell applications . The Tz unit, consisting of an electron‐deficient fused heterocyclic ring is a good electron acceptor, and exhibits high charge mobility, planarity, and intermolecular stacking …”