A Low-Bandgap Conjugated Copolymer Based on Porphyrin and Dithienocoronene Diimide with Strong Two-Photon Absorption

A new low-bandgap donor-acceptor (D-A) conjugated copolymer poly(DTCDI-POR) of planar acceptor dithienocoronene diimide (DTCDI) and strong donor porphyrin (POR) has been synthesized by Sonogashira coupling polymerization. Poly(DTCDI-POR) exhibits good thermal stability (decomposition temperature of 323 degrees C), strong absorption (molar extinction coefficient per repeat unit is 1.05 X 10(5) L mol(-1) cm(-1) at 468 nm in CHCl3 solution) in visible and near-infrared region (300-900 nm), low bandgap (1.44 eV), and strong two-photon absorption (2PA) at telecommunication wavelengths with 2PA cross sections per repeat unit as high as 7809 GM at 1520 nm.