Nanohybrid material based on carbazole-thiophene-functionalized MWCNT and grafted poly(3-hexylthiophene): Preparation, characterization and spectroelectrochemistry

•Nanohybrid based on MWCNT functionalized with carbazole and thiophene moieties.•Grafting of poly(3-hexylthiophene) promotes greater processability.•MWCNT influences on greater electrochemical, optical and electrochromic properties.•Greater performance achieved for the quaternary nanohybrid material. This work reports the preparation of two novel materials: a non-covalently bonded hybrid based on amino-carbazole-functionalized multi-walled carbon nanotube (MWCNTCO-NHCbz) and poly(3-dodecylthiophene) (P3DDT) and a covalently bonded nanohybrid based on MWCNT functionalized with 3,6-diamino-methylcarbazole (H2NCbzNH2), 3-carboxythiophene (ThCOOH) and a final grafting of poly(3-hexylthiophene) (P3HT). These materials were characterized by several spectroscopic techniques that proved their successfully preparation. Beyond the thermal, electrochemical, electrical and morphological characterizations, thin films of both materials were also tested by spectroelectrochemical experiments. The covalently bonded material presented a better electrochromic performance when compared with the other material: optical contrast three times higher (6%); coloration efficiency of 10.8 C−1 cm2; fast response times on the scale of few seconds; and greater long-term cyclability presenting a stable color changing memory and 73% of the original charge after 100 cycles. This enhanced performance might be related to the benefits provided by the covalent connections between the building blocks, such an important strategy of tailoring hybrid materials for multifunctional applications.