Click condensation approach to a narrow-bandgap benzobisthiazole-linked porphyrin-based conjugated microporous polymer for broadband optical switching

Abstract

Porphyrin-based conjugated microporous polymers (CMPs) with diverse linkage bonds have emerged as important optoelectronic materials. However, the development of new narrow band gap porphyrin-based CMPs is highly desired. In this work, by using 2,5-dimercapto-1,4-phenylenediamine and 5,10,15,20-(tetra-4-cyanophenyl)porphyrin as starting materials, a new conjugated porous benzobisthiazole-linked porphyrin-based polymer (BPP-1) is synthesized via a click condensation reaction between 1,2-aminothiol groups and cyano groups for the first time. The synthesized BPP-1 features a highly conjugated system with benzobisthiazole moieties as acceptors and porphyrin units as donors, which results in a band gap as narrow as 0.98 eV. The efficient π-conjugation of BPP-1 enables broadband nonlinear optical switching from saturable absorption to reverse saturable absorption under 532 nm and 1064 nm laser excitation. Based on the performance of BPP-1 under 1064 nm laser illumination, optical switching and light logic operations can be realized, demonstrating its potential for advanced optoelectronic applications.