Synthesis, photophysics and electroluminescent properties of a novel phenylene-ethynylene and bezothiadiazole alternating copolymer

A novel alternating conjugated polymer (C12-PPE-BT) containing phenylene-ethynylene and benzothiadiazole (BT) units (unless otherwise specified, C12-PPE-BT is represented that the BT ratio is 50% (mol%)) was synthesized by cross-coupling polycondensation with bis (triphenylphosphine)-dichloropalladium (Pd(PPh 3 ) 2 Cl 2 ) and phase transfer catalyst(PTC). C12-PPE-BT was characterized by 1 H NMR, IR, TGA, DSC and elemental analysis. Its electrochemistry, photophysics and electroluminescence properties were discussed. The copolymer obtained possesses high thermal stability, high oxidation and reduction potentials, and high photoluminescence quantum yield. Devices based on C12-PPE-BT copolymer emit red light with λ max = 620 nm. The emission of phenylene-ethynylene segments almost completely disappeared manifested that the intrachain and/or interchain energy transfer from phenylene-ethynylene segments to BT units occurred.