Single- and double-wall carbon nanotubes fully covered with tetraphenylporphyrins: Stability and optoelectronic properties from ab initio calculations

The optoelectronic properties of single- and double-wall carbon nanotubes (CNTs) noncovalently functionalized with tetraphenylporphyrins (TPPs) are addressed by dispersion-corrected ab initio calculations. Five CNT species with different chiralities were considered. We find that the most stable configurations are those where the CNTs are fully covered by TPPs, exhibiting binding energy of about 2 eV/TPP. The semiconducting CNT-TPP compounds show optical response characterized by a strong absorption associated to the TPP bands, with increasing intensity with the TPP concentration. In addition, molecular dynamic simulations show that the compounds would be stable at temperatures as high as 100°C.