Adsorption of pyrrole on Al12N12, Al12P12, B12N12, and B12P12 fullerene-like nano-cages; a first principles study

• Pyrrole adsorption on Al12N12, Al12P12, B12N12, and B12P12 surfaces has been investigated.
• Change in band gap (Eg) is more pronounced for boron nanocages than aluminum nanocages.
• The order of binding energies is Al12N12 > Al12P12 > B12N12 > B12P12.
• All these nano-clusters are p-type semiconductors.

Adsorption of pyrrole on the surfaces of four X12Y12 semiconductors (Al12N12, Al12P12, B12N12, and B12P12) is studied through density functional theory (DFT) calculations at B3LYP/6-31G(d,p) level of theory. The highest interaction energy is calculated for the adsorption of pyrrole on the surface of Al12N12 nano-cage. The adsorption energies of pyrrole on Al12N12, Al12P12, B12N12, and B12P12 are −64.6, −42.6, −12.0, −9.2 kJ mol−1, respectively. Pyrrole acts as an electron donor and adsorbs at the electrophilic site of nano-cage. Charge transfer to aluminum nano-cages is higher than to boron nano-cages. Changes in electronic properties such as band gap, Fermi level, and densities of states are also analyzed in order to better understand the sensing abilities of nano-cages for pyrrole molecule. Band gaps of aluminum nano-cages (Al12N12 and Al12P12) are unaffected by adsorption of pyrrole because of comparable effect on HOMOs and LUMOs. On the other hand, band gaps of boron nano-cages are significantly reduced on adsorption of pyrrole. Boron nano-cages are better sensor for pyrrole molecule despite their lower binding energies.