ABSTRACT
Understanding the interaction between fullerene (C60) and perovskite surfaces is pivotal for advancing the efficiency and stability of perovskite solar cells. In this study, we investigate the adsorption behavior of C60 on methylammonium lead iodide (MAPbI3) surfaces using periodic density functional theory calculations. We explore various surface terminations and defect configurations to elucidate the influence of surface morphology on the C60-perovskite interaction, computing the adsorption energy and transfer of charge. Our results reveal distinct adsorption energies and charge transfer mechanisms for different surface terminations, shedding light on the role of surface defects in modifying the electronic structure and stability of perovskite materials. Furthermore, we provide insights into the potential of C60 to passivate surface defects, playing a relevant role in the surface reconstruction after the formation of defects. This comprehensive understanding of C60-perovskite interactions offers valuable guidelines about the role of fullerenes on surface structure and reconstruction.
ABSTRACT
An approach to modulating the properties of carbon nanorings by incorporating pyrrolo[3,2-b]pyrrole units is of particular interest due to the combined effect of heteroatom and antiaromatic character on electronic properties. The inclusion of units other than phenylene leads to the formation of stereoisomers. In this work, we computationally study how the spatial orientation of monomeric units in the ring affects the properties of cyclic dibenzopyrrolo[3,2-b]pyrroles and their complexes with C60 fullerene. For [4]PP and [4]DHPP, the most symmetrical AAAA isomer is the most stable and forms stronger interactions with fullerene than the isomers where one or two monomeric units are flipped, mostly due to less Pauli repulsion. π-Electron delocalization in the monomeric unit is crucial for directing the electron transfer (from or to nanoring). The energy of excited states with charge transfer depends on the HOMO-LUMO gap, which varies from one stereoisomer to another only for [4]DHPPâC60 with aromatic 1,4-dihydropyrrolo[3,2-b]pyrrole units. The rates of electron transfer and charge recombination reactions are relatively weakly dependent of the spatial isomerism of nanorings.
Subject(s)
Fullerenes , Isomerism , Electron Transport , Carbon , PyrrolesABSTRACT
The Diels-Alder cycloaddition reaction between 1,3-cyclohexadiene and a series of C60 fullerenes with encapsulated (super)alkali/(super)halogen species (Li+@C60, Li2F+@C60, Cl-@C60, and LiF2-@C60) was explored by means of DFT calculations. The reactivity of the ion encapsulating systems was compared to that of the parent C60 fullerene. Significant enhancement in reactivity was found for cation-encapsulating Li+/Li2F+@C60 complexes. The cycloadduct formed by LiF2-@C60 was found to be the most thermodynamically favorable among the studied ones. In contrast, encapsulation of Cl- anions disfavors the cycloaddition reaction both kinetically and thermodynamically. Higher activation energy barrier and less stability of the reaction product in the case of Cl-@C60 were associated with the higher deformation energies of the fullerene cage and the lower interaction energy between the reactants in comparison with the other studied complexes.
