In the case of complexes Phos-C44 to Phos-C70, the bandgap decreasing emerges due to stabilization of the LUMO level of phosphorene. Considering related 2D materials such as graphene, the fullerene adsorption induces bandgap opening of ∼0.3-0.4 eV , which is due to the stress/strain externally exerted by fullerenes on the substrate structure . Therefore, we can conclude bandgap modulation in phosphorene could result from charge transfer and/or stress-strain effects exerted upon fullerene attachment. About the reliability of these results, periodic DFT calculations have predicted bandgap values of 1.0 eV for Phos-C60 complexes , which agrees with this work (HL=1.1 eV for Phos-C60). Moreover, we compute bandgap values of 1.7 eV for C60 and C70, which agree with those reported via photothermal deflection spectra and temperaturedependent microwave conductivity measurements : 1.6-1.8 eV (C60) and 1.6 eV (C70). The latter ensures the reliability of the employed theoretical methodology. Regarding the topology of frontier molecular orbitals in the complexes (Fig. ), covalent complexes show the HOMO located in both phosphorene and fullerene moieties due to the orbital interactions. However, the fullerene contribution to the HOMO decreases as the chemical bonding character decreases until it almost disappears in non-covalent complexes. Conversely, LUMO is almost entirely located in fullerene for all the complexes. Thus, fullerenes act as active sites for orbital-controlled interactions, mainly retaining their donor/acceptor properties when chemisorbed on phosphorene. While fullerene mainly will act as acceptor sites when physisorbed on phosphorene.